Daikin DCG Series User manual

©2018 - 2019
5151 San Felipe St., Suite 500, Houston, TX 77056
www.daikinac.com
ATTENTION INSTALLING PERSONNEL:
Prior to installation, thoroughly familiarize yourself with
this Installation Manual. Observe all safety warnings.
During installation or repair, caution is to be observed.
It is your responsibility to install the product safely and
to educate the customer on its safe use.
RECOGNIZE THIS SYMBOL
AS A SAFETY PRECAUTION.
These installation instructions cover the outdoor installation
of single package heating and cooling units. See the
Specication Sheet applicable to your model for information
regarding accessories.
*NOTE: Please contact your distributor or our website for
the applicable Specication Sheet referred to in this manual.
This Forced Air Central Unit Design Complies With
Requirements Embodied in the American National Standard
/ National Standard of Canada shown below.
ANSI Z21.47•CSA-2.3 CeNtrAl FurNACeS
DCG SERIES
LIGHT COMMERCIAL PACKAGED GAS UNIT
15 to 25 ToN
Our continuing commitment to quality products may mean a change in specications without notice.
IOD-1030A
03/2019
Index
Replacement Parts .........................................................2
Safety Instructions .........................................................2
General Information .......................................................5
Unit Location...................................................................5
Clearances ......................................................................8
Roof Curb Post-Installation Checks .............................8
Roof Top Duct Connections ..........................................8
Rigging Details ...............................................................8
Electrical Wiring .............................................................9
NOTE: 15 & 20 ton model shown in picture.
25 ton model has 2 fans.
O NLY PERSONNEL THAT HAVE BEEN TRAINED TO INSTALL , ADJUST , SERVICE OR
REPAIR ( HEREINAFTER , “ SERVICE ”) THE EQUIPMENT SPECIFIED IN THIS MANUAL
SHOULD SERVICE THE EQUIPMENT . T HE MANUFACTURER WILL NOT BE RESPONSIBLE
FOR ANY INJURY OR PROPERTY DAMAGE ARISING FROM IMPROPER SERVICE OR
SERVICE PROCEDURES . I F YOU SERVICE THIS UNIT , YOU ASSUME
RESPONSIBILITY
FOR
ANY
INJURY
OR PROPERTY DAMAGE WHICH MAY RESULT . I N ADDITION , IN
JURISDICTIONS THAT REQUIRE ONE OR MORE LICENSES TO SERVICE THE EQUIPMENT
SPECIFIED IN THIS MANUAL , ONLY LICENSED PERSONNEL SHOULD SERVICE THE
EQUIPMENT . I MPROPER INSTALLATION , ADJUSTMENT , SERVICING OR REPAIR OF
THE EQUIPMENT SPECIFIED IN THIS MANUAL , OR ATTEMPTING TO INSTALL , ADJUST ,
SERVICE OR REPAIR THE EQUIPMENT SPECIFIED IN THIS MANUAL WITHOUT PROPER
TRAINING MAY RESULT IN PRODUCT DAMAGE , PROPERTY DAMAGE , PERSONAL
INJURY OR DEATH
.
INSTALLATION INSTRUCTIONS
WARNING
PROP 65 WARNING
FOR CALIFORNIA CONSUMERS
Cancer and Reproductive Harm -
www.P65Warnings.ca.gov
0140M00517-A

2
REPLACEMENT PARTS
OrDerING PArtS
When reporting shortages or damages, or ordering repair
parts, give the complete unit model and serial numbers
as stamped on the unit’s nameplate.
Replacement parts for this appliance are available
through your contractor or local distributor. For the
location of your nearest distributor, consult the white
business pages, the yellow page section of the local
telephone book or contact:
EQUIPMENT SUPPORT
DAIKIN NORTH AMERICA LLC
19001 KERMIER ROAD
WALLER, TEXAS 77484
855-770-5678
SAFETY INSTRUCTIONS
tOthe INStAller
Before installing this unit, please read this manual to
familiarize yourself on the specic items which must be
adhered to, including maximum external static pressure
to unit, air temperature rise and minimum or maximum
CFM.
Keep this literature in a safe place for future reference.
IFTHE INFORMATION IN THESE INSTRUCTIONS IS NOT FOLLOWED
EXACTLY, AFIRE OR EXPLOSION MAY RESULT CAUSING PROPERTY
DAMAGE, PERSONAL INJURY OR LOSS OF LIFE.
DONOT STORE OR USE GASOLINE OR OTHER FLAMMABLE VAPORS AND
LIQUIDS IN THE VICINITY OF THIS OR ANY OTHER APPLIANCE.
DONOT TRY TO LIGHT ANY APPLIANCE.
DONOT TOUCH ANY ELECTRICAL SWITCH; DO NOT USE ANY PHONE
IN YOUR BUILDING.
IMMEDIATELY CALL YOUR GAS SUPPLIER FROM ANEIGHBOR’S
PHONE. FOLLOW THE GAS SUPPLIER’SINSTRUCTIONS.
IFYOU CANNOT REACH YOUR GAS SUPPLIER, CALL THE FIRE
DEPARTMENT.
INSTALLATION AND SERVICE MUST BE PERFORMED BY AQUALIFIED
INSTALLER, SERVICE AGENCY OR THE GAS SUPPLIER.
WHAT TO DO IF YOU SMELL GAS:
�
�
�
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WARNING
S HOULD OVERHEATING OCCUR OR THE GAS SUPPLY FAIL TO SHUT OFF
,
TURN OFF THE MANUAL GAS SHUTOFF VALVE EXTERNAL TO THE
FURNACE BEFORE TURNING OFF THE ELECTRICAL SUPPLY .
WARNING
SHEET METAL PARTS, SCREWS, CLIPS AND SIMILAR ITEMS INHERENTLY
HAVE SHARP EDGES, AND IT IS NECESSARY THAT THE INSTALLER AND
SERVICE PERSONNEL EXERCISE CAUTION.
CAUTION
Gas Supply Piping........................................................ 11
Propane Gas Installations ...........................................13
Circulating Air and Filters............................................14
Venting...........................................................................14
Condensate Drain Connection....................................14
Startup, Adjustments, and Checks .............................15
Air ow Adjustments....................................................16
Motor Sheave Adjustments .........................................17
Gas System Check .......................................................17
Normal Sequence Of Operation - heating ..................20
Normal Sequence Of Operation - Cooling..................21
Maintenance..................................................................22
Troubleshooting ...........................................................24
Appendix A Blower Performance Data .......................26
Appendix B Electrical Data..........................................29
Appendix C Unit Dimensions ......................................30
Appendix D Wiring Diagrams......................................31
Start-up checklist .........................................................46
Failure to follow the safety warnings exactly could result in
serious injury, death or property damage.
Never test for gas leaks with an open ame.
Use a commercially available soap solution made specically
for the detection of leaks to check all connections. A re or
explosion may result causing property damage, personal injury
or loss of life.
WARNING
FIRE OR EXPLOSION HAZARD
AVERTISSEMENT
RISQUE D’INCENDIE OU D’EXPLOSION
Si les consignes de sécurité ne sont pas suivies à la lettre, cela
peut entraîner la mort, de graves blessures ou des dommages
matériels.
Ne jamais vérier la présence de fuites de gaz au moyen d’une
amme nue. Vérier tous les raccords en utilisant une solution
savonneuse commerciale conçue spécialement pour la détection
de fuites. Un incendie ou une explosion risque de se produire,
ce qui peut entraîner la mort, des blessures ou des dommages
matériels.

3
D O NOT CONNECT TO OR USE ANY DEVICE THAT IS NOT DESIGN
CERTIFIED BY THE MANUFACTURER FOR USE WITH THIS UNIT . S ERIOUS
PROPERTY DAMAGE , PERSONAL INJURY , REDUCED UNIT PERFORMANCE
AND / OR HAZARDOUS CONDITIONS MAY RESULT FROM THE USE OF
SUCH NON - APPROVED DEVICES .
WARNING
T HIS UNIT MUST NOT BE USED AS A “ CONSTRUCTION HEATER ” DURING
THE FINISHING PHASES OF CONSTRUCTION ON A NEW STRUCTURE . T HIS
TYPE OF USE MAY RESULT IN PREMATURE FAILURE OF THE UNIT DUE TO
EXTREMELY LOW RETURN AIR TEMPERATURES AND EXPOSURE TO
CORROSIVE OR VERY DIRTY ATMOSPHERES .
WARNING
HIGH VOLTAGE !
D ISCONNECT ALL POWER BEFORE SERVICING OR
INSTALLING THIS UNIT . M ULTIPLE POWER SOURCES MAY
BE PRESENT . F AILURE TO DO SO MAY CAUSE PROPERTY
DAMAGE , PERSONAL INJURY OR DEATH .
WARNING
T O PREVENT THE RISK OF PROPERTY DAMAGE , PERSONAL INJURY OR
DEATH , DO NOT STORE COMBUSTIBLE MATERIALS OR USE GASOLINE OR
OTHER FLAMMABLE LIQUIDS OR VAPORS IN THE VICINITY OF THIS
APPLIANCE .
WARNING

4
WARNING
CARBON MONOXIDE POISONING HAZARD
Failure to follow the steps outlined below for each appliance
connected to the venting system being placed into operation
could result in carbon monoxide poisoning or death.
The following steps shall be followed with each appliance
connected to the venting system placed in operation, while any
other appliances connected to the venting system are not in
operation:
1. Seal any unused openings in the venting system.
2. Inspect the venting system for proper size and horizontal
pitch, as required by the National Fuel Gas Code, ANSI Z223.1 or
the Natural Gas and Propane Installation Code,
CSA B149.1-15 and these instructions. Determine that there is no
blockage or restriction, leakage, corrosion and other decien-
cies which could cause an unsafe condition.
3. As far as practical, close all building doors and windows and
all doors between the space in which the appliance(s) connect-
ed to the venting system are located and other spaces of the
building.
4. Close replace dampers.
5. Turn on clothes dryers and any appliance not connected to
the venting system. Turn on any exhaust fans, such as range
hoods and bathroom exhausts, so they shall operate at maxi-
mum speed. Do not operate a summer exhaust fan.
6. Follow the lighting instructions. Place the appliance being
inspected in operation. Adjust thermostat so appliance shall
operate continuously.
7. Test for spillage from draft hood appliances at the draft hood
relief opening after 5 minutes of main burner operation. Use the
ame of a match or candle.
8. If improper venting is observed during any of the above tests,
the venting system must be corrected in accordance with the
National Fuel Gas Code ANSI Z223.1/NFPA 54 and/or National
Gas and Propane Installation Code CSA B149.1-15.
9. After it has been determined that each appliance connected
to the venting system properly vents when tested as outlined
above, return doors, windows, exhaust fans, replace dampers
and any other gas burning appliance to their previous
conditions of use.
AVERTISSEMENT
RISQUE D’INTOXICATION AU MONOXYDE DE
CARBONE
Si les étapes décrites ci-dessous ne sont pas suivies pour
chacun des appareils raccordés au système de ventilation au
moment de sa mise en marche, cela peut entraîner une intoxica-
tion au monoxyde de carbone ou la mort. Les étapes suivantes
doivent être suivies pour chacun des appareils raccordés au
système de ventilation au moment de sa mise en marche, alors
que tous les autres appareils raccordés au système de ventila-
tion ne sont pas en marche :
1) Sceller toutes les ouvertures inutilisées du système de
ventilation.
2) Inspecter le système de ventilation an de vérier si la taille
et l’inclinaison par rapport à l’horizontale sont conformes aux
exigences du National Fuel Gas Code, ANSI Z223.1/NFPA 54 ou
du Code d’installation du gaz naturel et du propane, CSA B149.1
et à ces instructions. Vérier qu’il n’y a pas d’obstruction ou
de restriction, de fuite, de corrosion et d’autres problèmes qui
pourraient entraîner une situation dangereuse.
3) Si possible, fermer toutes les portes et fenêtres du bâtiment
ainsi que toutes les portes séparant l’endroit où se trouvent
les appareils raccordés au système de ventilation et les autres
zones du bâtiment.
4) Fermer le registre des foyers.
5) Mettre les sécheuses en marche ainsi que tous les autres
appareils qui ne sont pas raccordés au système de ventilation.
Mettre en marche tous les ventilateurs de tirage, comme celui
des hottes de cuisine et des salles de bains, et les régler à la
puissance maximale. Ne pas mettre en marche les ventilateurs
d’été.
6) Suivre les instructions d’allumage. Mettre en marche l’appa-
reil soumis à l’inspection. Régler le thermostat de manière à ce
que l’appareil fonctionne en continu.
7) Vérier la présence de fuite au niveau de l’ouverture du
coupe-tirage des appareils qui en sont dotés après 5 minutes
de fonctionnement du brûleur principal. Utiliser la amme d’une
allumette ou d’une bougie.
8) Si un problème de ventilation est observé pendant l’un des
essais décrits ci-dessus, des correctifs doivent être apportés
au système de ventilation conformément au National Fuel Gas
Code, ANSI Z223.1/NFPA 54 et (ou) au Code d’installation du gaz
naturel et du propane, CSA B149.1.
9) Une fois qu’il a été déterminé que chaque appareil raccordé
au système de ventilation fonctionne correctement au moyen
des essais décrits ci-dessus, les portes, les fenêtres, les ven-
tilateurs, les registres de foyer et tous les autres appareils de
combustion alimentés au gaz doivent être remis dans leur état
initial.

5
GENERAL INFORMATION
For complete information and installation instructions
for models with DDC controls, see manual DK-DDC-
TGD-XXX.
T O PREVENT PROPERTY DAMAGE , PERSONAL INJURY OR DEATH DUE TO
FIRE , EXPLOSIONS , SMOKE , SOOT , CONDENSATION , ELECTRIC SHOCK OR
CARBON MONOXIDE , THIS UNIT MUST BE PROPERLY INSTALLED ,
REPAIRED , OPERATED AND MAINTAINED .
WARNING
This unit is approved for outdoor installation ONLY. Rated
performance is achieved after 72 hours of operation. Rated
performance is delivered at the specied airow. See outdoor
unit specication sheet for split system models or product
specication sheet for packaged and light commercial models.
Specication sheets can be found at www.daikinac.com for
Daikin brand products. Within the website, please select the
residential or commercial products menu and then select the
submenu for the type of product to be installed, such as air
conditioners or heat pumps, to access a list of product pages
that each contain links to that model’s specication sheet.
To assure that your unit operates safely and efciently, it
must be installed, operated, and maintained in accordance
with these installation and operating instructions, all local
building codes and ordinances, or in their absence, with the
latest edition of the National Fuel Gas Code NFPA54/ANSI
Z223.1 and National Standard of Canada CAN/CSA B149
Installation Codes.
ePA reGulAtIONS
ImPOrtANt: the uNIteD StAteS eNvIrONmeNtAl PrOteCtION
AGeNCy (ePA) hAS ISSueD vArIOuS reGulAtIONS reGArDING
the INtrODuCtION AND DISPOSAl OF reFrIGerANtS IN thIS
uNIt. FAIlure tO FOllOw theSe reGulAtIONS mAy hArm the
eNvIrONmeNt AND CAN leAD tO the ImPOSItION OF SubStANtIAl
FINeS. beCAuSe reGulAtIONS mAy vAry Due tO PASSAGe OF New
lAwS, we SuGGeSt ACertIFIeD teChNICIAN PerFOrm ANy wOrk
DONe ON thIS uNIt. ShOulD yOu hAve ANy queStIONS PleASe
CONtACt the lOCAl OFFICe OF the ePA.
NAtIONAl CODeS
This product is designed and manufactured to permit instal-
lation in accordance with National Codes. It is the installer’s
responsibility to install the product in accordance with National
Codes and/or prevailing local codes and regulations.
The heating and cooling capacities of the unit should be greater
than or equal to the design heating and cooling loads of the
area to be conditioned. The loads should be calculated by an
approved method or in accordance with ASHRAE Guide or
Manual J - Load Calculations published by the Air Conditioning
Contractors of America.
Obtain from:
American National Standards Institute
25 West 43rd Street, 4th Floor
New York, NY 10036
System design and installation should also, where applicable,
follow information presented in accepted industry guides such
as the ASHRAE Handbooks. The manufacturer assumes no
responsibility for equipment installed in violation of any code
or regulation. The mechanical installation of the packaged roof
top units consists of making nal connections between the unit
and building services; supply and return duct connections; and
drain connections (if required). The internal systems of the unit
are completely factory-installed and tested prior to shipment.
Units are generally installed on a steel roof mounting curb as-
sembly which has been shipped to the job site for installation
on the roof structure prior to the arrival of the unit. The model
number shown on the unit’s identication plate identies the
various components of the unit such as refrigeration tonnage,
heating input and voltage.
Carefully inspect the unit for damage including damage to
the cabinetry. Any bolts or screws which may have loosened
in transit must be re-tightened. In the event of damage, the
receiver should:
1. Make notation on delivery receipt of any visible
damage to shipment or container.
2. Notify carrier promptly and request an inspection.
3. In case of concealed damage, carrier should be
notied as soon as possible-preferably within 5 days.
4. File the claim with the following supporting documents:
a. Original Bill of Lading, certied copy, or indemnity
bond.
b. Original paid freight bill or indemnity in lieu thereof.
c. Original invoice or certied copy thereof, showing
trade and other discounts or reductions.
d. Copy of the inspection report issued by carrier
representative at the time damage is reported to
the carrier. The carrier is responsible for making
prompt inspection of damage and for a thorough
investigation of each claim. The distributor or
manufacturer will not accept claims from dealers for
transportation damage.
NOTE: When inspecting the unit for transportation damage,
remove all packaging materials. Recycle or dispose of the
packaging material according to local codes.
Pre-INStAllAtION CheCkS
Carefully read all instructions for the installation prior to in-
stalling unit. Ensure each step or procedure is understood
and any special considerations are taken into account before
starting installation. Assemble all tools, hardware and sup-
plies needed to complete the installation. Some items may
need to be purchased locally.
UNIT LOCATION
T O PREVENT POSSIBLE EQUIPMENT DAMAGE , PROPERTY DAMAGE ,
PERSONAL INJURY OR DEATH , THE FOLLOWING BULLET POINTS MUST BE
OBSERVED WHEN INSTALLING THE UNIT .
WARNING
IMPORTANT NOTE: Remove wood shipping rails prior to
installation of the unit. See important note under Roof Curb
Installation Only.

6
All INStAllAtIONS:
ImPOrtANt NOte: Unit should be energized 24 hours pri-
or to compressor start up to ensure crankcase heater
has sufciently warmed the compressors. Compressor
damage may occur if this step is not followed.
NOTE: This appliance is a dedicated downow design.
Proper installation of the unit ensures trouble-free operation.
Improper installation can result in problems ranging from
noisy operation to property or equipment damages, danger-
ous conditions that could result in injury or personal property
damage. Damage or repairs due to improper installation
are not covered under the warranty. Give this booklet to the
user and explain it’s provisions. The user should retain these
instructions for future reference.
• For proper ame pattern within the heat exchanger
and proper condensate drainage, the unit must be
mounted level.
• The ue outlet must be at least 12 inches from any
opening through which flue gases could enter a
building, and at least three feet above any forced
air inlet located within ten feet. The economizer/
manual fresh air intake/motorized fresh air intake
and combustion air inlet mounted on the unit are not
affected by this restriction.
• To avoid possible corrosion of the heat exchanger,
do not locate the unit in an area where the outdoor
air (i.e. combustion air for the unit) will be frequently
contaminated by compounds containing chlorine or
uorine. Common sources of such compounds include
swimming pool chemicals and chlorine bleaches, paint
stripper, adhesives, paints, varnishes, sealers, waxes
(which are not yet dried) and solvents used during
construction and remodeling. Various commercial and
industrial processes may also be sources of chlorine/
uorine compounds.
• To avoid possible illness or death of the building
occupants, do NOT locate outside air intake device
(economizer, manual fresh air intake, motorized
fresh air intake) too close to an exhaust outlet, gas
vent termination, or plumbing vent outlet. For specic
distances required, consult local codes.
• Allow minimum clearances from the enclosure for
re protection, proper operation, and service access
(see unit clearances). These clearances must be
permanently maintained.
• The combustion air inlet and ue outlet on the unit
must never be obstructed. If used, do not allow the
economizer/manual fresh air damper/ motorized fresh
air damper to become blocked by snow or debris. In
some climates or locations, it may be necessary to
elevate the unit to avoid these problems.
• Damper must be in open position when appliance main
burner(s) is operating.
Le registre doit être ouvert lorsque tout brûleur principal
de l’appareil est en état de fonctionnement.
• When the unit is heating, the temperature of the return
air entering the unit must be between 50° F and 100° F.
GrOuND level INStAllAtIONS ONly:
• When the unit is installed on the ground adjacent
to the building, a level concrete (or equal) base is
recommended. Prepare a base that is 3” larger than
the package unit footprint and a minimum of 3” thick.
• The base should also be located where no runoff of
water from higher ground can collect in the unit.
rOOF tOP INStAllAtIONS ONly:
•To avoid possible property damage or personal injury,
the roof must have sufcient structural strength to
carry the weight of the unit(s) and snow or water
loads as required by local codes. Consult a structural
engineer to determine the weight capabilities of the
roof.
• The unit may be installed directly on wood oors or on
Class A, Class B, or Class C roof covering material.
• To avoid possible personal injury, a safe, at surface
for service personnel should be provided.
•As indicated on the unit data plate, a minimum
clearance of 36” to any combustible material is
required on the furnace access side of the unit. All
combustible materials must be kept out of this area.
•This 36” clearance must also be maintained to
insure proper combustion air and ue gas ow. The
combustion air intake and furnace ue discharge must
not be blocked for any reason, including blockage by
snow.
• Adequate clearances from the furnace ue discharge
to any adjacent public walkways, adjacent buildings,
building openings or openable windows must be
maintained in accordance with the latest edition of
the National Fuel Gas Code (ANSI Z223.1)
•Minimum horizontal clearance of 48” from the furnace
ue discharge to any electric meters, gas meters,
regulators and relief equipment is required.
uNIt PreCAutIONS
• Do not stand or walk on the unit.
• Except for holes in the wiring entrances (see Figure
below), do not drill holes anywhere in panels or in the
base frame of the unit. Unit access panels provide
structural support.
• Do not remove any access panels until unit has been
installed on roof curb or eld supplied structure.
• Do not roll unit across nished roof without prior
approval of owner or architect.
• Do not skid or slide on any surface as this may
damage unit base. The unit must be stored on a at,
level surface. Protect the condenser coil because it
is easily damaged.
Delete rec.

7
Delete rec.
rOOF Curb INStAllAtIONS ONly:
Before installing this unit...
IMPORTANT NOTE: This unit has been equipped with a
shipping brace under the compressor section that MUST BE
REMOVED before installing the unit on a roof curb.
Please follow the instructions below to remove brace.
W HEN UNIT IS SUSPENDED , BOARDS AND SHIPPING BRACE WILL DROP WHEN
SCREWS ARE REMOVED . T O PREVENT PERSONAL INJURY , STAND CLEAR.
R
EMOVE FORK HOLE BRACKETS , BOARDS AND SHIPPING BRACE FROM BOTTOM
OF
UNIT BEFORE PLACING UNIT ONTO CURB .
CAUTION
1. Remove wooden struts and shipping brace per
installation instructions. The struts are located
in the fork holes and are used to protect the unit
from damage while lifting with forks. The shipping
brace is located under the unit (under compressor).
Also remove the fork hole brackets as shown in the
following gure.
2. Locate and remove the end brackets as shown in the
following gure.
LIFT OVER APPROXIMATE
CENTER OF UNIT
SPREADER BARS
MUST BE USED WITH
LIFTING STRAPS THAT
ARE LESS THAN 16
FEET L ONG
REMOVE 2 BRACKETS
ON EACH END TO
REMOVE
WOODEN STRUTS
REMOVE 2 BRACKETS
ON EACH END TO
REMOVE
SHIPPING BRACE
3. Lift unit per the “Rigging Details” section of this manual,
observing all warnings and cautions. When unit is
lifted, boards and shipping brace will drop if screws
have been removed. To avoid injury, STAND CLEAR.
4. Dispose of the boards and brace appropriately.
Curb installations must comply with local codes and should
be done in accordance with the established guidelines of the
National Roong Contractors Association.
Proper unit installation requires that the roof curb be rmly
and permanently attached to the roof structure. Check for ad-
equate fastening method prior to setting the unit on the curb.
Full perimeter roof curbs are available from the factory and
are shipped unassembled. Field assembly, squaring, leveling
and mounting on the roof structure are the responsibility of
the installing contractor. All required hardware necessary
for the assembly of the sheet metal curb is included in the
curb accessory.
T O PREVENT POSSIBLE EQUIPMENT DAMAGE , PROPERTY DAMAGE ,
PERSONAL INJURY OR DEATH , THE FOLLOWING BULLET POINTS MUST BE
OBSERVED WHEN INSTALLING THE UNIT .
WARNING
• Sufcient structural support must be determined prior
to locating and mounting the curb and package unit.
• Ductwork must be constructed using industry
guidelines. The duct work must be placed into the
roof curb before mounting the package unit. Our full
perimeter curbs include duct connection frames to be
assembled with the curb. Cantilevered type curbs are
not available from the factory.
• Curb insulation, cant strips, ashing and general
roong material are furnished by the contractor.
The curbs must be supported on parallel sides by roof mem-
bers. The roof members must not penetrate supply and return
duct opening areas as damage to the unit might occur.
NOTE: The unit and curb accessories are designed to
allow vertical duct installation before unit placement. Duct
installation after unit placement is not recommended.
A LL CURBS LOOK SIMILAR . T O AVOID INCORRECT CURB POSITIONING ,
CHECK JOB PLANS CAREFULLY AND VERIFY MARKINGS ON CURB
ASSEMBLY . I NSTRUCTIONS MAY VARY IN CURB STYLES AND SUPERCEDE
INFORMATION SHOWN .
CAUTION
See the manual shipped with the roof curb for assembly and
installation instructions.

8
CLEARANCES
75"
48"
48"
6" 36" MINIMUM
ROOF OVERHANG
UNIT CLEARANCES
Clearance in accordance with local installation codes, the
requirements of the gas supplier and the manufacturer’s
installation instructions.
Dégaugement conforme aux codes d’installation locaux,
aux exigences du fournisseur de gaz et aux instructions
d’installation du fabricant.
Adequate clearance around the unit should be kept for safety,
service, maintenance, and proper unit operation. A clearance
of 75” on the service side of the unit is recommended to fa-
cilitate possible blower assembly, shaft, wheel replacement,
coil, heat exchanger, electric heat and gas furnace removal.
This unit must not be installed beneath any obstruction. This
unit should be installed remote from all building exhausts to
inhibit ingestion of exhaust air into the unit’s fresh air intake.
NOTE: If the 48” minimum is used on the control panel side
of a DCG unit, a ue extension (MF# 220-GX-03) needs be
to installed to prevent ue gas recirculation.
.
NOTE: 15 & 20 ton models have 3 fans.
25 ton models have 2 fans.
INSULATED
PANELS
ROOF CURB INSTALLATION
ROOF CURB POST-INSTALLATION CHECKS
After installation, check the top of the curb, duct connection
frame and duct anges to make sure gasket has been applied
properly. Gasket should be rmly applied to the top of the
curb perimeter, duct anges and any exposed duct connec-
tion frame. If gasket is loose, re-apply using strong weather
resistant adhesive.
Protrusion
Inspect curb to ensure that none of the utility services (electric)
routed through the curb protrude above the curb.
I F PROTRUSIONS EXIST , DO NOT ATTEMPT TO SET UNIT ON CURB .
I
NFORMATION SHOWN .
CAUTION
ROOF TOP DUCT CONNECTIONS
Install all duct connections on the unit before placing the unit
on rooftop.
RIGGING DETAILS
T O PREVENT PROPERTY DAMAGE , THE UNIT SHOULD REMAIN IN AN
UPRIGHT POSITION DURING ALL RIGGING AND MOVING OPERATIONS .
T
O FACILITATE LIFTING AND MOVING WHEN A CRANE IS USED , PLACE
THE UNIT IN AN ADEQUATE CABLE SLING .
WARNING
D O NOT LIFT UNITS TWO AT A TIME . P ROVISIONS FOR FORKS HAVE BEEN
INCLUDED IN THE UNIT BASE FRAME . M INIMUM FORK LENGTH IS 72” TO
PREVENT DAMAGE TO THE UNIT .
CAUTION
Provisions for forks have been included in the unit base frame.
No other fork locations are approved.
T O PREVENT POSSIBLE EQUIPMENT DAMAGE , PROPERTY DAMAGE ,
PERSONAL INJURY OR DEATH , THE FOLLOWING BULLET POINTS MUST BE
OBSERVED WHEN INSTALLING THE UNIT .
WARNING
• Unit must be lifted by the four lifting holes located at
the base frame corners.
• Lifting cables should be attached to the unit with
shackles.
• The distance between the crane hook and the top of
the unit must not be less than 60”.
• Two spreader bars must span over the unit to prevent
damage to the cabinet by the lift cables. Spreader
bars must be of sufcient length so that cables do
not come in contact with the unit during transport.
Remove wood struts mounted beneath unit base
frame before setting unit on roof curb. These struts
are intended to protect unit base frame from fork lift
damage. Removal is accomplished by extracting the
sheet metal retainers and pulling the struts through
the base of the unit. Refer to rigging label on the unit.

9
Important: If using bottom discharge with roof curb, ductwork
should be attached to the curb prior to installing the unit.
Ductwork dimensions are shown in Roof Curb Installation
Instructions.
Refer to the Roof Curb Installation Instructions for proper curb
installation. Curbing must be installed in compliance with the
National Roong Contractors Association Manual.
Lower unit carefully onto roof mounting curb. While rigging
unit, center of gravity will cause condenser end to be lower
than supply air end.
W HEN UNIT IS SUSPENDED , BOARDS AND SHIPPING BRACE WILL DROP WHEN
SCREWS ARE REMOVED . T
O PREVENT PERSONAL INJURY , STAND CLEAR.
R
EMOVE FORK HOLE BRACKETS , BOARDS AND SHIPPING BRACE FROM BOTTOM
OF
UNIT BEFORE PLACING UNIT ONTO CURB .
CAUTION
To assist in determining rigging requirements, unit weights
are shown as follows:
COMPRESSOR 1
COMPRESSOR 2
CG
EVAPORATORCOILS
A
B
C
XD
Y
CORNER & CENTER OF GRAVITY LOCATIONS
(l bs)
Corner Wei ght - A 582 645 627
Corner Wei ght - B 475 527 525
Corner Wei ght - C 565 589 604
Corner Wei ght - D 461 481 521
Unit Shipping Weight 2198 2357 2513
Unit Operating Weight 2083 2242 2283
X (Inches) 65" 63" 65.6"
Y (Inches) 40" 40" 40.5"
DATA
15 Tons
20 Tons
25 Tons

NOTE: These weights are without accessories installed.
T O PREVENT SEVERE DAMAGE TO THE BOTTOM OF THE UNIT , DO NOT
FORK LIFT UNIT AFTER WOOD STRUTS HAVE BEEN REMOVED .
CAUTION
Bring condenser end of unit into alignment with the curb. With
condenser end of the unit resting on curb member and using
curb as a fulcrum, lower opposite end of the unit until entire
unit is seated on the curb. When a rectangular cantilever
curb is used, care should be taken to center the unit. Check
for proper alignment and orientation of supply and return
openings with duct.
rIGGING remOvAl
T O PREVENT DAMAGE TO THE UNIT , DO NOT ALLOW CRANE HOOKS AND
SPREADER BARS TO REST ON THE ROOF OF THE UNIT .
CAUTION
Remove spreader bars, lifting cables and other rigging
equipment.
ELECTRICAL WIRING
HIGH VOLTAGE !
D ISCONNECT ALL POWER BEFORE SERVICING OR
INSTALLING THIS UNIT . M ULTIPLE POWER SOURCES MAY
BE PRESENT . F AILURE TO DO SO MAY CAUSE PROPERTY
DAMAGE , PERSONAL INJURY OR DEATH .
WARNING
HIGH VOLTAGE !
T O AVOID PERSONAL INJURY OR DEATH
DUE TO ELECTRICAL
SHOCK , DO NOT TAMPER WITH FACTORY WIRING . T HE
INTERNAL
POWER AND CONTROL WIRING
OF THESE UNITS
ARE FACTORY - INSTALLED AND HAVE BEEN THOROUGHLY
TESTED PRIOR TO SHIPMENT . C ONTACT
YOUR LOCAL
REPRESENTATIVE IF ASSISTANCE IS REQUIRED .
WARNING

10
T O PREVENT DAMAGE TO THE WIRING , PROTECT WIRING FROM SHARP
EDGES . F OLLOW NATIONAL ELECTRICAL CODE AND ALL LOCAL CODES
AND ORDINANCES . D O NOT ROUTE WIRES THROUGH REMOVABLE
ACCESS PANELS .
CAUTION
C ONDUIT
AND FITTINGS MUST BE WEATHER -
TIGHT TO
PREVENT
WATER
ENTRY INTO THE BUILDING .
CAUTION
For unit protection, use a fuse or HACR circuit breaker that is
in excess of the circuit ampacity, but less than or equal to the
maximum overcurrent protection device. DO NOT EXCEED
THE MAXIMUM OVERCURRENT DEVICE SIZE SHOWN
ON UNIT DATA PLATE.
All line voltage connections must be made through weath-
erproof ttings. All exterior power supply and ground wiring
must be in approved weatherproof conduit.
The main power supply wiring to the unit and low voltage
wiring to accessory controls must be done in accordance with
these instructions, the latest edition of the National Electrical
Code (ANSI/NFPA 70), and all local codes and ordinances.
The main power supply shall be three-phase, three wire.
The unit is factory wired for the voltage shown on the unit’s
data plate.
NOTE: If supply voltage is 208V, all leads on primary of
transformer(s) must be moved from the 230V to the 208V tap.
Main power wiring should be sized for the minimum circuit am-
pacity shown on the unit’s database. Size wires in accordance
with the ampacity tables in Article 310 of the National Elec-
trical Code. If long wires are required, it may be necessary
to increase the wire size to prevent excessive voltage drop.
Wires should be sized for a maximum of 3% voltage drop.
T O AVOID PROPERTY DAMAGE OR PERSONAL INJURY DUE TO FIRE , USE
ONLY COPPER CONDUCTORS .
CAUTION
T O PREVENT
IMPROPER AND DANGEROUS
OPERATION DUE TO
WIRING
ERRORS , LABEL ALL WIRES PRIOR TO DISCONNECTION WHEN SERVICING
CONTROLS . V ERIFY PROPER OPERATION AFTER SERVICING .
CAUTION
NOTE: A weather-tight disconnect switch, properly sized
for the unit total load, must be eld or factory installed. An
external eld supplied disconnect may be mounted on the
exterior panel.
Ensure the data plate is not covered by the eld-supplied
disconnect switch.
• Some disconnect switches are not fused. Protect the
power leads at the point of distribution in accordance
with the unit data plate.
• The unit must be electrically grounded in accordance
with local codes or, in the absence of local codes,
with the latest edition of the National Electrical Code
(ANSI-NFPA 70). A ground lug is provided for this
purpose. Size grounding conductor in accordance
with Table 250-95 of the National Electrical Code.
Do not use the ground lug for connecting a neutral
conductor.
• Connect power wiring to the electrical middle contactor
within the main control box of power block, if equipped.
Low Voltage
Terminal Strip
Thermostat wiring
for all units
connect to low
voltage strip
Ground
Lug
Line voltage connects
to power block on
Coolers, 230V Gas
Packs, and 2 Speed
Models.
Line voltage connects
to middle contactor
on 460v and 575v
Gas Packs
(or power block
if equipped)
Power Block -
(Coolers, 230V Gas
Packs, and 2 Speed
Models)
Field wiring enters
from this direction
POWER AND LOW VOLTAGE BLOCK LOCATIONS
Route field
control wiring
through
grommet
Field connec�on for
control wiring
at terminal block
Field
connec�on
for
line voltage
Ground Lug
Field wiring
enters from
this direc�on
LOW
HIGH
25 TONS MODEL POWER AND LOW VOLTAGE BLOCK
LOCATIONS
NOTE: Depending on the options installed, the location of the
components may vary in some models.

11
F AILURE OF UNIT DUE
TO OPERATION ON IMPROPER LINE VOLTAGE
OR WITH EXCESSIVE PHASE UNBALANCE CONSTITUTES PRODUCT
ABUSE AND IS NOT COVERED BY THE WARRANTY . I T MAY CAUSE
SEVERE DAMAGE TO THE UNIT ELECTRICAL COMPONENTS .
WARNING
AreAS wIthOut CONveNIeNCe Outlet
It is recommended that an independent 115V power source
be brought to the vicinity of the roof top unit for portable lights
and tools used by the service mechanic.
NOTE: Refer to local codes for requirements. These outlets
can also be factory installed.
uNItS INStAlleD ON rOOF tOPS
Main power and low voltage wiring may enter the unit through
the side or through the roof curb. Install conduit connectors
at the desired entrance locations. External connectors must
be weatherproof. All holes in the unit base must be sealed
(including those around conduit nuts) to prevent water leak-
age into building. All required conduit and ttings are to be
eld supplied.
Supply voltage to roof top unit must not vary by more than
10% of the value indicated on the unit data plate. Phase
voltage unbalance must not exceed 2%. Contact your local
power company for correction of improper voltage or phase
unbalance.
ELECTRICAL ENTRANCE LOCATIONS
Unit is equipped with a Low Voltage Terminal Block and has
Single Point wiring to the contactor.
lOw vOltAGe CONtrOl wIrING
1. A 24V thermostat must be installed for unit
operation. It may be purchased with the unit or
eld -supplied. Thermostats may be programmable
or electromechanical as required.
2. Locate thermostat or remote sensor in the conditioned
space where it will sense average temperature. Do not
locate the device where it may be directly exposed to
supply air, sunlight or other sources of heat. Follow
installation instructions packaged with the thermostat.
3. Use #18 AWG wire for 24V control wiring runs not
exceeding 75 feet. Use #16 AWG wire for 24V control
wiring runs not exceeding 125 feet. Use #14 AWG wire
for 24V control wiring runs not exceeding 200 feet.
Low voltage wiring may be National Electrical Code
(NEC) Class 2 where permitted by local codes.
4. Route thermostat wires from sub-base terminals to
the unit. Control wiring should enter through the duct
panel (dimple marks entrance location). Connect
thermostat and any accessory wiring to low voltage
terminal block TB1 in the main control box.
NOTE: Field-supplied conduit may need to be installed
depending on unit/curb conguration. Use #18 AWG solid
conductor wire whenever connecting thermostat wires to
terminals on sub-base. DO NOT use larger than #18 AWG
wire. A transition to #18 AWG wire may be required before
entering thermostat sub-base.
NOTE: Refer to unit wiring diagrams for thermostat hookups.
GAS SUPPLY PIPING
T O PREVENT
PERSONAL INJURY OR DEATH DUE TO IMPROPER
INSTALLATION , ADJUSTMENT , ALTERATION , SERVICE OR MAINTENANCE ,
REFER TO THIS MANUAL . F OR ADDITIONAL ASSISTANCE OR
INFORMATION , CONSULT A
QUALIFIED
INSTALLER , SERVICE
AGENCY OR
THE GAS SUPPLIER .
WARNING
IMPORTANT NOTE: This unit is factory set to operate on
natural gas at the altitudes shown on the rating plate.
T O PREVENT PROPERTY DAMAGE , PERSONAL INJURY OR DEATH WHEN
EITHER
USING PROPANE GAS ALONE OR AT HIGHER ALTITUDES , OBTAIN
AND INSTALL THE PROPER CONVERSION KIT ( S ). F AILURE TO DO SO CAN
RESULT IN UNSATISFACTORY OPERATION AND / OR EQUIPMENT DAMAGE .
H
IGH ALTITUDE KITS ARE FOR U.S. I NSTALLATIONS ONLY AND ARE NOT
APPROVED FOR USE IN C ANADA .
WARNING
The rating plate is stamped with the model number, type of
gas and gas input rating. Make sure the unit is equipped to
operate on the type of gas available. Conversion to propane
(LP) gas is permitted with the use of the factory authorized
conversion kit (see the unit Technical Manual for the appro-
priate kit). For High Altitude derates, refer to the latest edition
of the National Fuel Gas Code NFPA 54/ANSI Z223.1.
Installation of this furnace at altitudes above 7000 ft
(2134 m) shall be made in accordance with the Listed High
Altitude Conversion Kit available with this furnace.
L’installation de ce générateur de chaleur à des altitudes
supérieures à 7000 pi (2134 m) doit être effectuée
conformément aux instructions accompagnant la trousse
de conversion pour haute altitude fournie avec cet appareil.

12
NATURAL Min. 5.0" W.C., Max. 10.0" W.C.
PROPANE Min. 11.0" W.C., Max. 14.0" W.C.
INLET GAS PRESSURE
Inlet Gas Pressure Must Not Exceed the Maximum Value Shown in Table
Above.
The minimum supply pressure should not vary from that
shown in the table above because this could prevent the
unit from having dependable ignition. In addition, gas input
to the burners must not exceed the rated input shown on the
rating plate. Overring of the unit could result in premature
heat exchanger failure.
PIPING
IMPORTANT NOTE: To avoid possible unsatisfactory opera-
tion or equipment damage due to under ring of equipment,
do not undersize the natural/propane gas piping from the
meter/tank to the unit. When sizing a trunk line, include all
appliances on that line that could be operated simultaneously.
The rating plate is stamped with the model number, type of
gas and gas input rating. Make sure the unit is equipped to
operate on the type of gas available. The gas line installa-
tion must comply with local codes, or in the absence of local
codes, with the latest edition of the National Fuel Gas Code
NFPA 54/ANSI Z223.1.
Natural Gas Connection
1/2 3/4 11 1/4 1 1 /2
10 132 278 520 1050 1600
20 92 190 350 730 1100
30 73 152 285 590 980
40 63 130 245 500 760
50 56 115 215 440 670
60 50 105 195 400 610
70 46 96 180 370 560
80 43 90 170 350 530
90 40 84 160 320 490
100 38 79 150 305 460
Pressure= .50 PSIG or less and Pressure Drop of 0.3" W.C.
(Based on 0.60 Specific Gravity Gas)
Natural Gas Capacity of Pipe
in Cubic Feet of Gas Per Hour (CFH)
Nominal Black Pipe Size (inches)
Length of
Pipe in Feet
Heating Value of Gas (BTU/Cubic Foot
CFH =
BTUH Furnace Input
Refer to the Proper Piping Practice drawing for the general
layout at the unit. The following rules apply:
1. Use black iron pipe and ttings for the supply piping.
The use of a ex connector and/or copper piping is
permitted as long as it is in agreement with local
codes.
2. Use pipe joint compound on male threads only. Pipe
joint compound must be resistant to the action of the
fuel used.
3. Use ground joint unions.
4. Install a drip leg to trap dirt and moisture before it can
enter the gas valve. The drip leg must be a minimum
of three inches long.
5. Use two pipe wrenches when making connection to
the gas valve to keep it from turning.
6. Install a manual shut-off valve in a convenient location
(within six feet of unit) between the meter and the unit.
7. Tighten all joints securely.
8. The unit must be connected to the building piping by
one of the following methods:
• Rigid metallic pipe and ttings
• Semirigid metallic tubing and metallic fittings
(Aluminum alloy tubing must not be used in exterior
locations)
• Listed gas appliance connectors used in accordance
with the terms of their listing that are completely in
the same room as the equipment
• In the prior two methods above the connector or
tubing must be protected from physical and thermal
damage. Aluminum alloy tubing and connectors must
be coated to protect against external corrosion when
in contact with masonry, plaster or insulation or are
subject to repeated wettings by liquids (water - not
rain water, detergents or sewage).
46-1/10”
GAS INLET LOCATION (3/4” NPT)
46-1/10”46-1/10”
74-11/12”
HOOD LOCATED
INSIDE HEAT SECTION
DURING SHIPPING
DOOR
PROVIDE
CLEARANCE
FOR REMOVAL OF
ACCESS PANELS
DRIP LEG
GROUND
JOINT
UNION
MANUAL
SHUT OFF
VALVE
PROPER PIPING PRACTICE

13
NOTE: The unit gas supply entrance is factory sealed with
plugs. Keep plugs in place until gas supply is ready to be
installed. Once ready, replace the plugs with the supplied
grommets and install gas supply line.
GAS PIPING CheCkS
T O PREVENT PROPERTY DAMAGE OR PERSONAL INJURY DUE TO FIRE ,
THE FOLLOWING INSTRUCTIONS MUST BE PERFORMED REGARDING GAS
CONNECTIONS AND PRESSURE TESTING :
• T HE UNIT AND ITS GAS CONNECTIONS MUST BE LEAK TESTED
BEFORE PLACING IN OPERATION . B ECAUSE OF THE DANGER OF
EXPLOSION OR FIRE , NEVER USE A MATCH OR OPEN FLAME TO TEST
FOR LEAKS . N EVER EXCEED SPECIFIED PRESSURES FOR TESTING .
H IGHER PRESSURE MAY DAMAGE GAS VALVE AND CAUSE
OVERFIRING WHICH MAY RESULT IN PREMATURE HEAT EXCHANGE
FAILURE .
• T HIS UNIT AND ITS SHUT - OFF VALVE MUST BE DISCONNECTED FROM
THE GAS SUPPLY DURING ANY PRESSURE TESTING OF THAT SYSTEM
AT TEST PRESSURES IN EXCESS OF 1/2 PSIG (3.48 K P A ).
• T HIS UNIT MUST BE ISOLATED FROM THE GAS SUPPLY SYSTEM BY
CLOSING ITS MANUAL SHUT - OFF VALVE DURING ANY PRESSURE
TESTING OF THE GAS SUPPLY PIPING SYSTEM AT TEST PRESSURES
EQUAL TO OR LESS THAN 1/2 PSIG (3.48 K P A ).
CAUTION
T O AVOID PROPERTY
DAMAGE OR PERSONAL INJURY ,
BE SURE THERE IS
IN THE VICINITY DURING AIR BLEEDING . NO OPEN FLAME
WARNING
There will be air in the gas supply line after testing for leaks
on a new installation. Therefore, the air must be bled from
the line by loosening the ground joint union until pure gas is
expelled. Tighten union and wait for ve minutes until all gas
has been dissipated in the air. Be certain there is no open
ame in the vicinity during air bleeding procedure. The unit is
placed in operation by closing the main electrical disconnect
switch for the unit.
PROPANE GAS INSTALLATIONS
T O AVOID PROPERTY DAMAGE , PERSONAL INJURY OR DEATH DUE TO
FIRE OR EXPLOSION CAUSED BY A PROPANE GAS LEAK , INSTALL A GAS
DETECTING WARNING DEVICE . S INCE RUST CAN REDUCE THE LEVEL OF
ODORANT IN PROPANE GAS , A GAS DETECTING WARNING DEVICE IS THE
ONLY RELIABLE WAY TO DETECT A PROPANE GAS LEAK . C ONTACT A
LOCAL PROPANE GAS SUPPLIER ABOUT INSTALLING A GAS DETECTING
WARNING DEVICE .
WARNING
IMPORTANT NOTE: Propane gas conversion kits must be
installed to convert units to propane gas.
All propane gas equipment must conform to the safety
standards of the National Board of Fire Underwriters (See
NBFU Manual 58). Line pressure 11.3 - 14” w.c.
For satisfactory operation, propane gas manifold pressure
must be within 9.7 - 10.3 inches w.c. for high re and within
6.7 - 7.3 inches w.c. low re at the manifold with all gas
appliances in operation. Maintaining proper gas pressure
depends on three main factors:
1. Vaporization rate, which depends on (a) temperature of
the liquid, and (b) wetted surface area of the container
or containers.
2. Proper pressure regulation.
3. Pressure drop in lines between regulators, and between
second stage regulator and the appliance. Pipe size
required will depend on length of pipe run and total
load of all appliances.
tANkS AND PIPING
Complete information regarding tank sizing for vaporization,
recommended regulator settings and pipe sizing is
available from most regulator manufacturers and propane
gas suppliers.
Since propane gas will quickly dissolve white lead or most
standard commercial compounds, special pipe dope must
be used. Shellac base compounds resistant to the actions
of liqueed petroleum gases such as Gasolac®, Stalactic®,
Clyde’s®or John Crane®are satisfactory.
See following gure for typical propane gas piping.
200 PSIG
Maximum
5 to 15 PSIG
(20 PSIG Max.) Continuous
11" W.C.
Second Stage
Regulator
First Stage
Regulator
TYPICAL PROPANE GAS PIPING
rOOF tOP lOCAtION AND INStAllAtION
The gas supply piping location and installation for roof top units
must be in accordance with local codes or, in the absence
of locals codes, with ordinances of the latest edition of the
National Fuel Gas Code (ANSI Z223.1).
A manual gas shut off valve must be eld installed external
to the roof top unit. In addition, a drip leg must be installed
near the inlet connection. A ground joint union connection
is required between the external shut off valve and the unit
connection to the gas valve to permit removal of the burner
assembly for servicing.
1. Route gas piping to unit so that it does not interfere
with the removal of access panels. Support and align
piping to prevent strains or misalignment of the manifold
assembly.
2. All units are furnished with standard female NPT pipe
connections. Connection pipe size is 3/4” NPT. The
size of the gas supply piping to the unit must be based
on length of run, number of units on the system, gas
characteristics, BTU requirement and available supply
pressure. All piping must be done in accordance with
local codes or, in the absence of local codes, with the
latest edition of the National Fuel Gas Code (ANSI

14
Z223.1).
NOTE: The gas connection size at the unit does NOT
establish the size of the supply line.
3. These units are designed for either natural or
propane (LP) gas and are specically constructed at
the factory for only one of these fuels. The fuels are
NOT interchangeable. However, the furnace can be
converted in the eld from natural gas to LP gas with the
appropriate factory kit (see unit Technical Manual for the
appropriate kit). Only a qualied contractor, experienced
with natural and propane gas systems, should attempt
conversion. Kit instructions must be followed closely to
assure safe and reliable unit operation.
4. With all units on a common line operating under full re,
natural gas main supply pressure should be adjusted to
approximately 7.0” w.c., measured at the unit gas valve.
If the gas pressure at the unit is greater than 10.5” w.c.,
the contractor must furnish and install an external type
positive shut off service pressure regulator. The unit will
not function satisfactorily if supply gas pressure is less
than 5.5” w.c. or greater than 10.5” w.c..
NOTE: A minimum horizontal distance of 48” between
the regulator and the furnace ue discharge is required.
5. With all units on a common line operating under full LP
gas main supply pressure should be at least 11.0” w.c.
and must be no greater than 14.0” w.c., measured at
the unit gas valve. Unit will not function satisfactorily if
supply gas pressure is less than 11.0” w.c. or greater
than 14.0” w.c..
6. All pipe connections should be sealed with a pipe thread
compound, which is resistant to the fuel used with the
furnace. A soapy water solution should be used to check
all joints for leaks. A 1/8” NPT plugged tap is located
on the entering side of the gas valve for test gauge
connection to measure supply (main) gas pressure.
Another 1/8” tap is provided on the side of the manifold
for checking manifold pressure.
T HIS UNIT AND ITS INDIVIDUAL SHUTOFF VALVE MUST BE
DISCONNECTED FROM THE GAS SUPPLY SYSTEM DURING ANY
PRESSURE TESTING OF THAT SYSTEM AT TEST PRESSURES IN EXCESS OF
1/2 PSIG (13.8” W . C .).
WARNING
T HIS UNIT MUST BE I SOLATED FROM THE GAS SUPPLY PIPING SYSTEM
BY CLOSING ITS INDIVIDUAL MANUAL SHUTOFF VALVE DURING ANY
PRESSURE TESTING EQUAL TO OR LESS THAN 1/2 PSIG.
CAUTION
7. There must be no obstruction to prevent the ow of
combustion and ventilating air. A vent stack is not
required and must never be used. The power ventor
will supply an adequate amount of combustion air
as long as the air passageways are kept free of any
obstructions and the recommended external unit
clearances are maintained.
CIRCULATING AIR AND FILTERS
DuCtwOrk
The supply duct should be provided with an access panel
large enough to inspect the air chamber downstream of the
heat exchanger. A cover should be tightly attached to prevent
air leaks.
Ductwork dimensions are shown in the roof curb installation
manual.
If desired, supply and return duct connections to the unit may
be made with exible connections to reduce possible unit
operating sound transmission.
VENTING
NOTE: Venting is self-contained.
CONDENSATE DRAIN CONNECTION
CONDeNSAte DrAIN CONNeCtION
A 1” female NPT drain connection is supplied on the end of
the condensate pan, with an alternative connection on the
bottom of the pan. An extrnal trap must be installed for proper
condensate drainage.
Drain Pan (Side View)
NOTE: Trap should be deep enough to offset maximum
unit static difference. A minimum 4” trap is recommended.
Drain Plug Roof Curb
See NOTE
Base Rail
Open Vent 2” Min
DRAIN CONNECTION
Install condensate drain trap as shown. Use 1” drain line and
ttings or larger. Do not operate without trap.
hOrIZONtAl DrAIN
Drainage of condensate directly onto the roof may be accept-
able; (refer to local code). It is recommended that a small
drip pad of either stone, mortar, wood or metal be provided
to prevent any possible damage to the roof. When using the
horizontal drain connection, check the drain plug in bottom
connection to ensure it is tight.

15
CleANING
Due to the fact that drain pans in any air conditioning unit
will have some moisture in them, algae and fungus will
grow due to airborne bacteria and spores. Periodic clean-
ing is necessary to prevent this build-up from plugging the
drain.
STARTUP, ADJUSTMENTS, AND CHECKS
HIGH VOLTAGE!
T O AVOID PERSONAL INJURY OR DEATH DUE TO
ELECTRICAL SHOCK , BOND THE FRAME OF THIS UNIT TO
THE BUILDING ELECTRICAL GROUND BY USE OF THE
GROUNDING TERMINAL PROVIDED OR OTHER
ACCEPTABLE MEANS . D ISCONNECT ALL POWER BEFORE
SERVICING OR INSTALLING THIS UNIT .
WARNING
Pre-StArtuP INStruCtIONS - GeNerAl
T O PREVENT PROPERTY DAMAGE OR PERSONAL INJURY , D O NOT START
THE UNIT UNTIL ALL
NECESSARY PRE - CHECKS AND TEST HAVE BEEN
PERFORMED .
CAUTION
Prior to the beginning of Startup, Adjustments, and Checks
procedures, the following steps should be completed in the
building.
MOVING MACHINERY HAZARD!
T O PREVENT POSSIBLE PERSONAL INJURY OR DEATH , DISCONNECT
POWER TO THE UNIT AND PADLOCK IN THE “OFF” POSITION BEFORE
SERVICING FANS .
WARNING
This unit is equipped with an electronic ignition device to
automatically light the main burners. It also has a power vent
blower to exhaust combustion products.
On new installations, or if a major component has been re-
placed, the operation of the unit must be checked.
Check unit operation as outlined in the following instructions.
If any sparking, odors, or unusual sounds are encountered,
shut off electrical power and recheck for wiring errors, or ob-
structions in or near the blower motors. Duct covers must
be removed before operating unit.
The Startup, Adjustments, and Checks procedure provides
a step-by-step sequence which, if followed, will assure the
proper startup of the equipment in the minimum amount of
time. Air balancing of duct system is not considered part of
this procedure. However, it is an important phase of any air
conditioning system startup and should be performed upon
completion of the Startup, Adjustments, and Checks proce-
dure. The Startup, Adjustments, and Checks procedure at
outside ambients below 55°F should be limited to a readiness
check of the refrigeration system with the required nal check
and calibration left to be completed when the outside ambient
rises above 55°F.
temPOrAry heAtING OrCOOlING
If the unit is to be used for temporary heating or cooling, a
“Startup, Adjustments, and Checks” must rst be performed in
accordance with this manual. Damage or repairs due to failure
to comply with these requirements are not covered under the
warranty. After the machines are used for temporary heating
or cooling, inspect the coils, fans, and motors for unacceptable
levels of construction dust and dirt and install new lters.
CONtrACtOr reSPONSIbIlIty
The installing contractor must be certain that:
• All supply and return air ductwork is in place,
properly sealed, and corresponds with installation
instructions.
• All thermostats are mounted and wired in accordance
with installation instructions.
• All electric power, all gas, hot water or steam line
connections, and the condensate drain installation
have been made to each unit on the job. These
main supply lines must be functional and capable
of operating all units simultaneously.
• Requirements are met for venting and combution air.
• Air lters are in place.
• Input rate and temperature rise are adjusted per
rating plate.
rOOF Curb INStAllAtION CheCk
Inspect the roof curb for correct installation. The unit and curb
assembly should be level. Inspect the ashing of the roof
mounting curb to the roof, especially at the corners, for good
workmanship. Also check for leaks around gaskets. Note any
deciencies in a separate report and forward to the contractor.
ObStruCtIONS, FAN CleArANCe AND wIrING
Remove any extraneous construction and shipping materials
that may be found during this procedure. Rotate all fans
manually to check for proper clearances and that they ro-
tate freely. Check for bolts and screws that may have jarred
loose during shipment to the job site. Retighten if necessary.
Re-tighten all electrical connections.
FIelD DuCt CONNeCtIONS
Verify that all duct connections are tight and that there is no
air bypass between supply and return.
FIlter SeCtION CheCk
Remove lter section access panels and check that lters
are properly installed. Note airow arrows on lter frames.
Pre-StArtuP PreCAutIONS
It is important to your safety that the unit has been properly
grounded during installation. Check ground lug connection in
main control box for tightness prior to closing circuit breaker
or disconnect switch. Verify that supply voltage on line side
of disconnect agrees with voltage on unit identication plate
and is within the utilization voltage range as indicated in
Appendix C Electrical Data.

16
System Voltage - That nominal voltage value assigned to
a circuit or system for the purpose of designating its voltage
class.
Nameplate Voltage - That voltage assigned to a piece of
equipment for the purpose of designating its voltage class
and for the purpose of dening the minimum and maximum
voltage at which the equipment will operate.
Utilization Voltage - The voltage of the line terminals of the
equipment at which the equipment must give fully satisfactory
performance. Once it is established that supply voltage will
be maintained within the utilization range under all system
conditions, check and calculate if an unbalanced condition
exists between phases. Calculate percent voltage unbalance
as follows:
Three Phase Models
3) PERCENT VOLTAGE
UNBALANCE
2) MAXIMUM VOLTAGE DEVIATIONS
FROM AVERAGE VOLTAGE
1) AVERAGE VOLTAGE
HOW TO USE THE FORMULA:
EXAMPLE: With voltage of 220, 216, and 213
1) Average Voltage = 220+216+213=649 / 3 = 216
2) Maximum Voltage Deviations from Average Voltage = 220 - 216 = 4
3) Percent Voltage Unbalance = 100 x = = 1.8%
Percent voltage unbalance MUST NOT exceed 2%.
4
216
400
216
= 100 X
CONtrOl vOltAGe CheCk
Close the disconnect switch to energize control transformer.
Check primary and secondary (24V) of control transformer.
AIR FLOW ADJUSTMENTS
Refer to the following “Motor Sheave Adjustments” section.
When the nal adjustments are complete, the current draw of
the motor should be checked and compared to the full load
current rating of the motor. The amperage must not exceed
the service factor stamped on the motor nameplate. The total
airow must not be less than that required for operation of
the electric heaters or the furnace.
If an economizer is installed, check the unit operating bal-
ance with the economizer at full outside air and at minimum
outside air.
NOTE: Airow setting below 300 CFM/Ton is not recom-
mended, as evaporator freezing or poor unit performance
is possible.
For 2-speed models, airow adjustments must be made with
the evaporator motor operating at high speed (in 2nd stage
cooling or in heat mode). 2-speed models have a “V” in 11th
digit of the model number (e.g. DCC300XXX3V).
evAPOrAtOr FAN rOtAtION CheCk
Check that fan rotates clockwise when viewed from the drive
side of unit and in accordance with rotation arrow shown
on blower housing. If it does not, reverse any two incoming
power cables at Single Point Power Block. In this case, repeat
bearing check.
Do not attempt to change load side wiring. Internal wiring
assures all motors and compressors will rotate in correct direc-
tion once evaporator fan motor rotation check has been made.
eleCtrICAl INPut CheCk
Make preliminary check of evaporator fan ampere draw and
verify that motor nameplate amps are not exceeded. A nal
check of amp draw should be made upon completion of air
balancing of the duct system (see Appendix B).
Set evAPOrAtOr FAN rPm
Actual RPM’s must be set and veried with a tachometer or
strobe light. Refer to Appendices A and B for basic unit fan
RPM. Refer also to “Airow” section of this manual. With
disconnect switch open, disconnect thermostat wires from
terminals Y and W. This will prevent heating and mechanical
cooling from coming on. Place a jumper wire across terminals
R and G at TB1 terminal block. Close disconnect switch;
evaporator fan motor will operate so RPM can be checked.
For gas heat units, the airow must be adjusted so that the
air temperature rise falls within the ranges given stated on
Data Plate (see Appendix A - Blower Performance).
The drive on the supply fan is typically set in the middle of the
RPM range. The drive motor sheave pitch diameter is eld
adjustable for the required airow. Refer to “Motor Sheave
Adjustments” section.
Upon completion of the air ow balancing, we recommend
replacing the variable pitched motor sheave with a proper-
ly-sized xed sheave. A matching xed sheave will provide
longer belt and bearing life and vibration free operation. Ini-
tially, it is best to have a variable pitched motor sheave for the
purpose of airow balancing, but once the balance has been
achieved, xed sheaves maintain alignment and minimize
vibration more effectively.
beArING CheCk
Prior to energizing any fans, check and make sure that all
setscrews are tight so that bearings are properly secured to
shafts.
teNSION AND AlIGNmeNt ADjuStmeNt
Correct belt tension is very important to the life of your belt.
Too loose a belt will shorten its life; too tight, premature motor
and bearing failure will occur. Check you belt drive for ade-
quate “run-in” belt tension by measuring the force required to
deect the belt at the midpoint of the span length. Belt tension
force can be measured using a belt tension gauge, available
through most belt drive manufacturers.

17
SPANLENGTHt
*DEFLECTION
FORCE
h
C
d H
D
*Apply force to the center of the span.
t = Span length, inches
C = Center distance, inches
D = Larger sheave diameter, inches
d = Smaller sheave diameter, inches
h = Deection height, inches
DRIVE BELT TENSION ADJUSTMENT
MODEL
SHEAVE
DIAMETER
(in)
DEFLECTION
(in)
BELT DRIVE Used New
15 Ton
B, BA Standard 4.3 to 5.5 5.5 +.5 8.2 +.5 1/4 ± 1/16
20 Ton
B, BA Standard 4.3 to 5.5 5.5 +.5 8.2 +.5 1/4 ± 1/16
25 Ton
B, BA Standard 5.1 to 6.1 5.5 +.5 8.2 +.5 1/4 ± 1/16
DEFLECTION
FORCE (lbs)
TYPE
RECOMMENDED POUNDS OF FORCE PER BELT
When new V-belts are installed on a drive the initial tension
will drop rapidly during the rst few hours. Check tension
frequently during the rst 24 hours of operation. Subsequent
retensioning should fall between the minimum and maximum
force. To determine the deection distance from the normal
position, use a straightedge or stretch a cord from sheave to
sheave to use as a reference line. On multiple belt drives, an
adjacent undeected belt can be used as a reference.
MOTOR SHEAVE ADJUSTMENTS
vl, vm& 2vP vArIAble PItCh key tyPe mOtOr SheAveS
The driving and driven motor sheaves should be in alignment
with each other and the shafts parallel.
vl& vmSheAveS ADjuStmeNt
1. Loosen set screw “B” using a 5/32” Allen key.
2. Making half or full turns from closed position, adjust
sheave pitch diameter for desired speed. DO NOT
OPEN MORE THAN SIX FULL TURNS.
3. Tighten set screw “B” securely over at.
4. Carefully put on belts and adjust belt tension. DO NOT
FORCE BELTS OVER GROOVES.
5. Ensure all keys are in place and the set screws tight
before starting drive. Recheck set screws and belt
tension after 24 hours service.
NOTE: Future adjustments should be made by loosening the
belt tension and increasing or decreasing the pitch diameter
of the sheave by half or full turns as required. Readjust belt
tension before starting drive.
C
B
VL & VM
NOTE: Do not operate sheave with ange projecting beyond
the hub end.
GAS SYSTEM CHECK
Pre-Operation Checks
1. Close the manual gas valve external to the unit.
2. Turn off the electrical power supply to the unit.
3. Set the room thermostat to its lowest possible setting.
4. Remove the heat exchanger door on the side of the
unit by removing screws.
5. This unit is equipped with an ignition device which
automatically lights the main burner. DO NOT try to
light burner by any other method.
6. Move the gas control valve switch to the OFF position.
Do not force.
7. Wait ve minutes to clear out any gas.
8. Smell for gas, including near the ground. This is
important because some types of gas are heavier than
air. If you have waited ve minutes and you do smell
gas, immediately follow the warnings on page 3 of this
manual. If having waited for ve minutes and no gas
smell is noted, move the gas control valve switch to
the ON position.
9. Replace the heat exchanger door on the side of the
unit.
10. Open the manual gas valve external to the unit.
11. Turn on the electrical power supply to the unit.
12. Set the thermostat to desired setting.
GAS SuPPly PreSSureS & reGulAtOr ADjuStmeNtS
S HOULD OVERHEATING OCCUR OR THE GAS SUPPLY FAIL TO SHUT OFF ,
TURN OFF THE MANUAL GAS SHUTOFF VALVE EXTERNAL TO THE UNIT
BEFORE TURNING
OFF THE ELECTRICAL SUPPLY .
WARNING
T O AVOID PROPERTY DAMAGE , PERSONAL INJURY OR DEATH , DO NOT
FIRE GAS UNIT WITH FLUE BOX COVER REMOVED .
WARNING

18
NOTE: Except during brief periods when gas pressures are
being measured by qualied service personnel, the furnace
access panel must always be secured in place when the
furnace is in operation. An inspection port in the access panel
is provided to monitor the ame.
The rst step in checking out the gas-red furnace is to test
the gas supply piping to the unit for tightness and purge the
system of air using methods outlined in the latest edition of
the National Fuel Gas Code ANSI Z223.1. Verify that the
disconnect switch is in the “OFF” position. A soapy water
solution should be used to check for gas leaks. Since the
unit is subject to considerable jarring during shipment, it is
extremely important that all gas connections and joints be
tested for tightness. Gas piping downstream from the unit
inlet should be checked for leaks during the subsequent
sequence check.
The supply gas pressure should be adjusted to 7.0” w.c. on
natural gas and 11.0” on LP gas with the gas burners oper-
ating. If there is more than one unit on a common gas line,
the pressures should be checked with all units under full re.
A supply pressure tap is provided on the upstream side of
the gas valve. A manifold pressure tap is provided on the
manifold. The normal manifold pressure for full input is 3.5”
w.c. on natural gas and 10.0” w.c. for propane gas. Minimum
gas supply pressure is 5.5” w.c. for natural gas and 11.0” for
propane gas. In order to obtain rating, gas supply pressure
must be 11.0” w.c. for propane gas.
The pressure regulator on LP gas models is adjusted for 10.0”
w.c. manifold pressure and is intended to prevent over-ring
only. Do not attempt adjustment of the built-in pressure regu-
lator unless the supply pressure is at least 7.0” w.c. on natural
gas or 14.0” w.c. on propane gas. Check the location of the
ignition electrode and the ame sensor for correct gap setting.
Flame
Sensor
Ignitor
NATURAL PROPANE (LP)
350,000 750,000 #30 #48
400,000 850,000 #30 #48
GAS ORIFICES
MAXIMUM
INPUT
(BTUH)
NUMBER
of
BURNERS
MAXIMUM
BTUH/BURNER
HEAT EXCHANGER AND BURNER ORIFICE SPECIFICATIONS
NOTE: Gas appliances located more than 2000 feet above
sea level must be derated 4% per 1000 feet of total elevation
and that variance in gas heating value and specic gravity
require change in manifold pressure to obtain rating, it is
mandatory that the input be adjusted at the installation site. All
installations should be made as outlined in the latest edition of
the National Fuel Gas Code ANSI Z223.1, section “Procedures
To Be Followed To Place An Appliance in Operation”. Refer
also to the “User’s Information Manual” supplied with the unit
for additional information on the gas furnace.
Gas Supply And Manifold Check
Gas supply pressure and manifold pressure with the burners
operating must be as specied on the rating plate.
Gas Inlet Pressure Check
Gas inlet pressure must be checked and adjusted in accor-
dance to the type of fuel being consumed.
With Power And Gas Off:
1. Connect a water manometer or adequate gauge to
the inlet pressure tap of the gas valve.
Inlet gas pressure can also be measured by removing
the cap from the dripleg and installing a predrilled cap
with a hose tting.
With Power And Gas On:
2. Put unit into heating cycle and turn on all other gas
consuming appliances.
NATURAL Min. 5.0" W.C., Max. 10.0" W.C.
PROPANE Min. 11.0" W.C., Max. 14.0" W.C.
INLET GAS PRESSURE
NOTE: Inlet Gas Pressure Must Not Exceed the Maximum
Value Shown.
If operating pressures differ from above, make necessary
pressure regulator adjustments, check piping size, etc., and/
or consult with local utility.
Manifold Pressure Check
The gas valve has a tapped opening to facilitate measurement
of the manifold pressure. A “U” Tube manometer having a
scale range from 0 to 12 inches of water should be used for
this measurement. The manifold pressure must be measured
with the burners operating.
To adjust the pressure regulator, remove the adjustment screw
or cover on the gas valve. Turn out (counterclockwise) to
decrease pressure, turn in (clockwise) to increase pressure.
Only small variations in gas ow should be made by means of

19
the pressure regulator adjustment. In no case should the nal
manifold pressure vary more than plus or minus 0.3 inches
water column from the specied nominal pressure. Any major
changes in ow should be made by changing the size of the
burner orices. The measured input rate to the furnace must
not exceed the rating specied on the unit rating plate.
For natural gas, the manifold pressure must be between 3.2
and 3.8 inches w.c. (3.5 nom inal) for high re and between
1.7 and 2.3 inches w.c. (2.0 nominal) for low re.
For propane gas, the manifold pressure must be between 9.7
and 10.3 inches w.c. (10.0 nominal) for high re and between
6.7 and 7.3 inches w.c. (7.0 nominal) for low re.
Gas Input (Natural Gas Only) Check
It is the responsibility of the contractor to adjust the gas input
to the unit.
To measure the gas input use a gas meter and proceed
as follows:
1. Turn off gas supply to all other appliances except the
unit.
2. With the unit operating, time the smallest dial on the
meter for one complete revolution. If this is a 2 cubic
foot dial, divide the seconds by 2; if it is a 1 cubic foot
dial, use the seconds as is. This gives the seconds
per cubic foot of gas being delivered to the unit.
3. INPUT=GAS HTG VALUE x 3600 / SEC. PER CUBIC
FOOT
Example: Natural gas with a heating value of 1000 BTU per
cubic foot and 34 seconds per cubic foot as determined by
Step 2, then:
Input = 1000 x 3600 / 34 = 106,000 BTU per Hour.
NOTE: BTU content of the gas should be obtained
from the gas supplier. This measured input must not
be greater than shown on the unit rating plate.
Adjust input rate by varying the adjustment of the gas pressure
regulator on the gas valve. All adjustments must be made
with furnace operating at high re and at normal operating
temperature. A manometer should be connected to the gas
valve to verify pressure is within the specied range (see
following gures for manometer connections). Clockwise
rotation of the pressure regulator screw increases pressure
and gas ow rate. Turn screw counterclockwise to decrease
pressure and gas ow rate. After adjustment the furnace
temperature rise must be within the range specied on the
unit data plate. NOTE: Thermal efciency of the furnace is a
product efciency rating determined under continuous oper-
ating conditions independent of any installed system.
Pressure Regulator
Adjustment
(Under Cap Screw)
Gas Valve
On/Off
Selector
Switch
INLET OUTLET
Inlet Pressure
Ta p
Outlet Pressure
Ta p
WHITE-RODGERS 36G22 - SINGLE STAGE
Inlet
Pressure Boss
Low Fire
Regulator Adjust
Manometer
Manometer
Hose
High Fire Regulator
Adjust Regulator
Vent
Outlet
Pressure Boss
Open to
Atmosphere
WHITE-RODGERS 36G54 (2-STAGE) CONNECTED TO
MANOMETER
PRESSURE ADJUSTMENTS
TO CONNECT MANOMETER TO GAS VALVE:
1. Back outlet pressure test screw (inlet/outlet pressure
boss) out one turn (counterclockwise, not more than
one turn).
2. Attach a hose and manometer to the outlet pressure
boss of the valve.
TO REMOVE MANOMETER FROM GAS VALVE:
1. Remove manometer hose from outlet pressure boss.
2. Turn outlet pressure test screw in to seal pressure
port (clockwise, 7 in-lb. minimum).
3. Turn on electrical power and gas supply to the system.
4. Turn on system power and energize valve.
5. Using a leak detection solution or soap suds, check
for leaks at pressure boss screw. Bubbles forming
indicate a leak. SHUT OFF GAS AND FIX ALL LEAKS
IMMEDIATELY.

20
T O PREVENT UNRELIABLE OPERATION OR EQUIPMENT DAMAGE , THE
GAS MANIFOLD PRESSURE MUST BE AS
SPECIFIED ON THE
UNIT
RATING PLATE . O NLY MINOR ADJUSTMENTS SHOULD BE MADE BY
ADJUSTING THE GAS VALVE PRESSURE REGULATOR .
CAUTION
6. Relight all other appliances turned off in step 1. Be
sure all pilot burners are operating.
Main Burner Flame Check
Flames should be stable, soft and blue (dust may cause or-
ange tips but they must not be yellow) and extending directly
outward from the burner without curling, oating or lifting off.
Temperature Rise Check
Check the temperature rise through the unit by placing ther-
mometers in supply and return air registers as close to the
unit as possible. Thermometers must not be able to sample
temperature directly from the unit heat exchangers, or false
readings could be obtained.
1. All registers must be open; all duct dampers must be
in their nal (fully or partially open) position and the
unit operated for 15 minutes on HIGH FIRE before
taking readings.
2. The temperature rise must be within the range
specied on the rating plate.
NOTE: Air temperature rise is the temperature difference
between supply and return air.
With a properly designed system, the proper amount of
temperature rise will normally be obtained when the unit is
operated at rated input with the recommended blower speed.
If the correct amount of temperature rise is not obtained, it may
be necessary to change the blower speed. A higher blower
speed will lower the temperature rise. A slower blower speed
will increase the temperature rise.
NOTE: Blower speed MUST be set to give the correct air
temperature rise through the unit as marked on the rating
plate.
NORMAL SEQUENCE OF OPERATION - HEATING
This unit has one (RS) Manual Reset Limit Control Switch.
Check the limit to make sure it has not tripped. The limit may
arrive at the job site tripped as a result of shipping shock.
If the vent motor comes on, but the unit does not attempt
ignition, check if the ALS (Automatic Reset High Limit
Control Switch) requires resetting.
1. With electricity and gas turned on, the system switch
in the “HEAT” or “AUTO” position and the fan switch
in the “AUTO” position, the thermostat will close the
circuit between unit terminals R and W (R-W) when the
temperature falls below the thermostat setting.
2. D1 on IIC energizes relay VMR.
3. Relay VMR energizes the vent motor.
4. Operation of the vent motor closes the pressure switch
PS located in the burner compartment. the control then
initiates a 15-second pre-purge time delay. During
this period, the vent motor will clear the combustion
chamber of any residual gas.
5. After the pre-purge period, the ignition control energizes
the Wl-C gas valve and simultaneously initiates a “three
(3)-try” spark ignition sequence.
6. When the burners are ignited, a minimum four (4) micro-
amp DC current will ow through the ame between the
sensor electrode and the grounded burner.
7. When the controller proves that the ame has been
established, it will keep the gas valve energized and
discontinue the ignition spark. First stage manifold
pressure will be approximately 2.0” w.c. for natural gas
and 7.0” w.c. for propane (LP).
8. If the control is unable to ignite the burners after its
initial attempt, it will initiate another purge and spark
sequence. A third purge and spark sequence will be
initiated if the second attempt is unsuccessful. If the third
attempt is unsuccessful, the controller will close the gas
valve and lock itself out. It may be reset by momentarily
interrupting power. This may be accomplished by briey
lowering the room thermostat set-point below room
temperature, or by shutting off the main power to the
unit. (See TP-105 for more details.)
9. Integrated ignition control will close its normally open
contacts after a delay of approximately 30 seconds. This
action energizes contactor BC and starts the supply
fan motor. Operation of the supply fan circulates air
across the heat exchanger and delivers heated air to
the conditioned space.
10.When the space temperature rises, the thermostat will
open R-W. Opening R-W will cause the gas valve to
close, and the furnace to shut down.
11.The furnace has three high temperature limit controls,
which can shut down the burner. They do not shut down
the vent motor.
Unit Shutdown
1. Set the thermostat to lowest setting.
2. Turn off the electrical power supply to the unit.
3. Remove the heat exchanger door on the side of the
unit by removing screws.
4. Move the gas control valve switch to the OFF position.
Do not force.
5. Close manual gas shut off valve external to the unit.
6. Replace the heat exchanger door on the unit.
7. If cooling and/or air circulation will be desired, turn
ON the electrical power.
AutOmAtIC reSet hIGh lImIt CONtrOl (lS)
Located in the burner compartment on the heat exchanger, its
sensing element projects through the blower section bulkhead
and senses the temperature at the rear of the furnace. It will
cycle the furnace off if the temperature exceeds 100°F plus
maximum rise.