Daikin DFG Series User manual
RECOGNIZE THIS SYMBOL
AS A SAFETY PRECAUTION.
These installaon instrucons cover the outdoor installaon of sin-
gle package heang and cooling units. See the Specicaon Sheet
applicable to your model for informaon regarding accessories.
*NOTE: Please contact your distributor or our website for the ap-
plicable Specicaon Sheet referred to in this manual.
This Forced Air Central Unit Design Complies With Requirements
Embodied in the American Naonal Standard / Naonal Standard
of Canada shown below.
ANSI Z21.47•CSA-2.3 Central Furnaces
DFG SERIES
PACKAGED GAS/ELECTRIC UNIT
15 TO 25 ToN
Our continuing commitment to quality products may mean a change in specications without notice.
IOD-1055A
03/2023
Index
...................................................................2
Replacement Parts ..................................................................2
................................................................3
...........................................................................4
Clearances...............................................................................6
...........................................6
......................................................6
Rigging Details.........................................................................7
Electrical Wiring ......................................................................8
Gas Supply Piping ..................................................................10
......................................................11
.......................................................12
..................................................................................13
...............................................13
NOTE: 25 ton model shown in picture.
20 ton model has 4 fans
15 ton model has 3 fans
INSTALLATION INSTRUCTIONS
© 2022-2023
19001 Kermier Rd. Waller, TX 77484
www.daikincomfort.com
WARNING
WARNING
2
SAFETY INSTRUCTIONS
Before installing this unit, please read this manual to familiarize
yourself on the specic items which must be adhered to, includ-
ing maximum external stac pressure to unit, air temperature rise
and minimum or maximum CFM.
WARNING
- WHAT TO DO IF YOU SMELL GAS:
•
•
•
•
WARNING
CAUTION
WARNING
-
-
WARNING
WARNING
HIGH VOLTAGE
WARNING
REPLACEMENT PARTS
When reporng 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. Your nearest distributor can be lo-
cated online at or by contacng:
EQUIPMENT SUPPORT
DAIKIN COMFORT TECHNOLOGIES MANUFACTURING, L.P.
19001 KERMIER ROAD
WALLER, TEXAS 77484
855-770-5678
.........................................13
.............................................................14
..................................................................16
...............................18
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...........................................20
..............................21
Maintenance .........................................................................22
....................................................................24
Appendix A Blower Performance Data...................................26
Appendix B Electrical Data.....................................................44
Appendix C Unit Dimensions .................................................46
Appendix D Wiring Diagrams.................................................47
..................................................................59
3
GENERAL INFORMATION
WARNING
Rated performance is achieved aer 20 hours of op-
eraon. Rated performance is delivered at the specied airow.
See outdoor unit specicaon sheet for split system models or
product specicaon sheet for packaged and light commercial
models. Specicaon sheets can be found at www.daikincomfort.
com for Daikin brand products. Within the website, please select
the residenal or commercial products menu and then select the
submenu for the type of product to be installed, such as air condi-
oners or heat pumps, to access a list of product pages that each
contain links to that model’s specicaon sheet.
To assure that your unit operates safely and eciently, it must
be installed, operated, and maintained in accordance with these
installaon and operang instrucons, all local building codes and
ordinances, or in their absence, with the latest edion of the Na-
onal Fuel Gas Code NFPA54/ANSI Z223.1 and Naonal Standard
of Canada CAN/CSA B149 Installaon Codes.
-
-
-
This product is designed and manufactured to permit installaon
in accordance with Naonal Codes. It is the installer’s responsibil-
ity to install the product in accordance with Naonal Codes and/
or prevailing local codes and regulaons.
The heang and cooling capacies of the unit should be greater
than or equal to the design heang and cooling loads of the area
to be condioned. The loads should be calculated by an approved
method or in accordance with ASHRAE Guide or Manual J - Load Cal-
culaons published by the Air Condioning Contractors of America.
Obtain from:
American Naonal Standards Instute
25 West 43rd Street, 4th Floor
New York, NY 10036
System design and installaon should also, where applicable, fol-
low informaon presented in accepted industry guides such as the
ASHRAE Handbooks. The manufacturer assumes no responsibility
for equipment installed in violaon of any code or regulaon. The
mechanical installaon of the packaged roof top units consists of
making nal connecons between the unit and building services;
supply and return duct connecons; and drain connecons (if
required). The internal systems of the unit are completely facto-
ry-installed and tested prior to shipment.
Units are generally installed on a steel roof mounng curb assem-
bly which has been shipped to the job site for installaon on the
roof structure prior to the arrival of the unit. The model num-
ber shown on the unit’s idencaon plate idenes the various
components of the unit such as refrigeraon tonnage, heang in-
put and voltage.
Carefully inspect the unit for damage including damage to the
cabinetry. Any bolts or screws which may have loosened in tran-
sit must be re-ghtened. In the event of damage, the receiver
should:
1. Make notaon on delivery receipt of any visible damage
to shipment or container.
2. Nofy the carrier promptly and request an inspecon.
3. In case of concealed damage, the carrier should be no-
ed as soon as possible-preferably within 5 days.
B10259-216
CO can cause serious illness including permanent brain
Advertencia especial para la instalación de calentadores ó manejadoras
de aire en áreas cerradas como estacionamientos ó cuartos de servicio.
B10259-216
El monóxido de carbono puede causar enfermedades severas
como daño cerebral permanente ó muerte.
Las emisiones de monóxido de carbono pueden circular a través
del aparato cuando se opera en cualquier modo.
B10259-216
RISQUE D'EMPOISONNEMENT AU MONOXYDE DE CARBONE
Le monoxyde de
des
carbone peut causer des maladies graves telles que
dommages permanents au cerveau et meme la mort.
Cette ventilation est nécessaire pour éviter le danger d'intoxication
au CO pouvant survenir si un appareil produisant du monoxyde
de carbone continue de fonctionner au sein de la zone confinée.
4
4. File the claim with the following supporng documents:
a. Original Bill of Lading, cered copy, or indemnity
bond.
b. Original paid freight bill or indemnity in lieu thereof.
c. Original invoice or cered copy thereof, showing
trade and other discounts or reducons.
d. Copy of the inspecon report issued by the carrier
representave at the me damage is reported to the
carrier. The carrier is responsible for making prompt
inspecon of damage and for a thorough invesga-
on of each claim. The distributor or manufacturer
will not accept claims from dealers for transportaon
damage.
NOTE: When inspecng the unit for transportaon damage, re-
move all packaging materials. Recycle or dispose of the packaging
material according to local codes. Verify that the voltage listed on
the unit serial palate matches the voltage being supplied by the
building ulies.
NOTE: Verify that voltage listed on serial plate matches voltage
being supplied by site.
Carefully read all instrucons for the installaon prior to installing
unit. Ensure each step or procedure is understood and any special
consideraons are taken into account before starng installaon.
Assemble all tools, hardware and supplies needed to complete
the installaon. Some items may need to be purchased locally.
UNIT LOCATION
WARNING
IMPORTANT NOTE: Remove wood shipping rails prior to installa-
on of the unit. See important note under Roof Curb Installaon
Only.
Unit should be energized 24 hours prior to
compressor start up to ensure crankcase heater has suciently
warmed the compressors. Compressor damage may occur if this
step is not followed.
NOTE: This appliance is a dedicated downow design.
Proper installaon of the unit ensures trouble-free operaon. Im-
proper installaon can result in problems ranging from noisy op-
eraon to property or equipment damages, dangerous condions
that could result in injury or personal property damage. Damage
or repairs due to improper installaon are not covered under the
warranty. Give this booklet to the user and explain it’s provisions.
The user should retain these instrucons for future reference.
• For proper ame paern 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 open-
ing through which ue gases could enter a building, and
at least three feet above any forced air inlet located with-
in ten feet. The economizer/manual fresh air intake/mo-
torized fresh air intake and combuson air inlet mounted
on the unit are not aected by this restricon.
• To avoid possible corrosion of the heat exchanger, do
not locate the unit in an area where the outdoor air (i.e.
combuson air for the unit) will be frequently contam-
inated by compounds containing chlorine or uorine.
Common sources of such compounds include swimming
pool chemicals and chlorine bleaches, paint stripper, ad-
hesives, paints, varnishes, sealers, waxes (which are not
yet dried) and solvents used during construcon and re-
modeling. Various commercial and industrial processes
may also be sources of chlorine/uorine compounds.
• To avoid possible illness or death of the building occu-
pants, do NOT locate outside air intake device (econo-
mizer, manual fresh air intake, motorized fresh air intake)
too close to an exhaust outlet, gas vent terminaon, or
plumbing vent outlet. For specic distances required,
consult local codes.
• Allow minimum clearances from the enclosure for re
protecon, proper operaon, and service access (see
unit clearances). These clearances must be permanently
maintained.
• The combuson air inlet and ue outlet on the unit must
never be obstructed. If used, do not allow the economiz-
er/manual fresh air damper/ motorized fresh air damper
to become blocked by snow or debris. In some climates or
locaons, it may be necessary to elevate the unit to avoid
these problems.
• When the unit is heang, the temperature of the return
air entering the unit must be between 50° F and 100° F.
• When the unit is installed on the ground adjacent to the
building, a level concrete (or equal) base is recommend-
ed. 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 runo of water
from higher ground can collect in the unit.
• To avoid possible property damage or personal injury, the
roof must have sucient 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 deter-
mine the weight capabilies 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 combusble material is required on the fur-
nace access side of the unit. All combusble materials
must be kept out of this area.
5
• This 36” clearance must also be maintained to insure
proper combuson air and ue gas ow. The combuson
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, build-
ing openings or openable windows must be maintained
in accordance with the latest edion of the Naonal Fuel
Gas Code (ANSI Z223.1)
• Minimum horizontal clearance of 48” from the furnace
ue discharge to any electric meters, gas meters, regula-
tors and relief equipment is required.
• Do not stand or walk on the unit.
• Except for holes in the wiring entrances (see Figure be-
low), 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 unl unit has been in-
stalled on roof curb or eld supplied structure.
• Do not roll unit across nished roof without prior approv-
al 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.
IMPORTANT NOTE: This unit has been equipped with a shipping
brace under the compressor secon that MUST BE REMOVED
before installing the unit on a roof curb.
Please follow the instrucons below to remove brace.
CAUTION
1. Remove wooden struts and shipping brace per installa-
on instrucons. The struts are located in the fork holes
and are used to protect the unit from damage while liing
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 fol-
lowing gure.
LIFT OVER APPROXIMATE
CEN TER OF UNIT
SPREADER BARS
MUST BE USED WITH
LIFTING STRAPS THAT
ARE LESS THAN 16
FEET LONG
REMOVE 2 BRACKETS
ON EACH END TO
REMOVE
WOODEN STRUTS
REMOVE 2 BRACKETS
ON EACH END TO
REMOVE
SHIPPING BRACE
3. Li unit per the “Rigging Details” secon of this manual,
observing all warnings and cauons. When unit is lied,
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 installaons must comply with local codes and should be
done in accordance with the established guidelines of the Naon-
al Roong Contractors Associaon.
Proper unit installaon requires that the roof curb be rmly and
permanently aached to the roof structure. Check for adequate
fastening method prior to seng the unit on the curb.
Full perimeter roof curbs are available from the factory and are
shipped unassembled. Field assembly, squaring, leveling and
mounng on the roof structure are the responsibility of the in-
stalling contractor. All required hardware necessary for the as-
sembly of the sheet metal curb is included in the curb accessory.
WARNING
• Sucient structural support must be determined prior to
locang and mounng the curb and package unit.
6
• Ductwork must be constructed using industry guidelines.
The duct work must be placed into the roof curb before
mounng the package unit. Our full perimeter curbs in-
clude duct connecon frames to be assembled with the
curb. Canlevered type curbs are not available from the
factory.
• Curb insulaon, cant strips, ashing and general roong
material are furnished by the contractor.
• The curbs must be supported on parallel sides by roof
members. The roof members must not penetrate sup-
ply and return duct opening areas as damage to the unit
might occur.
NOTE: The unit and curb accessories are designed to allow ver-
cal duct installaon before unit placement. Duct installaon aer
unit placement is not recommended.
CAUTION
-
See the manual shipped with the roof curb for assembly and in-
stallaon instrucons.
CLEARANCES
UNIT CLEARANCES
Adequate clearance around the unit should be kept for safety,
service, maintenance, and proper unit operaon. A 75” clearance
on the non-service side of the unit is required to facilitate possi-
ble blower assembly, sha, wheel replacement and coil removal.
*DFG ONLY - A 75” clearance on the service is required for remov-
al of the gas heat exchanger. This unit must not be installed be-
neath any obstrucon. This unit should be installed remote from
all building exhausts to inhibit ingeson of exhaust air into the
unit’s fresh air intake.
NOTE: If the 48” minimum is used on the control panel side of a
DFG unit, a ue extension (220-DK-014) needs be to installed to
prevent ue gas recirculaon.
ROOF CURB INSTALLATION
Aer installaon, check the top of the curb, duct connecon 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 connecon frame. If gasket is
loose, re-apply using strong weather resistant adhesive.
Inspect curb to ensure that none of the ulity services (electric)
routed through the curb protrude above the curb.
NOTE: If the duct is to be fasten to the curb the screw should be
installed horizontally into the anges of the duct openings of the
curb.
CAUTION
ROOF TOP DUCT CONNECTIONS
Install all duct connecons on the unit before placing the unit on
rooop.
DFG
7
RIGGING DETAILS
WARNING
CAUTION
Provisions for forks have been included in the unit base frame. No
other fork locaons are approved.
WARNING
• Unit must be lied by the four liing holes located at the
base frame corners.
• Liing cables should be aached 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 li cables. Spreader bars
must be of sucient length so that cables do not come
in contact with the unit during transport. Remove wood
struts mounted beneath unit base frame before seng
unit on roof curb. These struts are intended to protect
unit base frame from fork li damage. Removal is ac-
complished by extracng the sheet metal retainers and
pulling the struts through the base of the unit. Refer to
rigging label on the unit.
IMPORTANT: If using with roof curb, ductwork should be aached
to the curb prior to installing the unit. Ductwork dimensions are
shown in Roof Curb Installaon Instrucons.
Refer to the Roof Curb Installaon Instrucons for proper curb
installaon. Curbing must be installed in compliance with the Na-
onal Roong Contractors Associaon Manual.
Lower unit carefully onto roof mounng curb. While rigging unit,
center of gravity will cause condenser end to be lower than supply
air end.
CAUTION
To assist in determining rigging requirements, unit weights are
shown in table below.
COMPRESSOR 1
COMPRESSOR 2
CG
EVAPORATORCOILS
A
B
C
XD
Y
CORNER & CENTER OF GRAVITY LOCATIONS
DATA
15T 20T 25T
Corner Weight - A 455 549 415
Corner Weight - B 520 490 609
Corner Weight - C 532 574 758
Corner Weight - D 403 566 487
Unit Shipping Weight 2025 2294 2385
Unit Operang Weight 1910 2179 2270
X (Inches) 68.07 63.59 60.18
Y (Inches) 42.58 42.70 42.56
NOTE: THESE WEIGHTS ARE WITHOUT ACCESSORIES INSTALLED.
8
CAUTION
Bring condenser end of unit into alignment with the curb. With
condenser end of the unit resng on curb member and using curb
as a fulcrum, lower opposite end of the unit unl enre unit is
seated on the curb. When a rectangular canlever curb is used,
care should be taken to center the unit. Check for proper align-
ment and orientaon of supply and return openings with duct.
CAUTION
Remove spreader bars, liing cables and other rigging equipment.
ELECTRICAL WIRING
WARNING
HIGH VOLTAGE
WARNING
HIGH VOLTAGE
CAUTION
CAUTION
For unit protecon, use a fuse or HACR circuit breaker that is in
excess of the circuit ampacity, but less than or equal to the maxi-
mum overcurrent protecon device. DO NOT EXCEED THE MAXI-
MUM OVERCURRENT DEVICE SIZE SHOWN ON UNIT DATA PLATE.
All line voltage connecons must be made through weatherproof
ngs. 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 in-
strucons, the latest edion of the Naonal 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 trans-
former(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 Arcle 310 of the Naonal Electrical
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.
CAUTION
CAUTION
-
NOTE: A weather-ght 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 pan-
el. Switch shall be provided to ensure all-pole disconnecon from
the supply mains.
Ensure the data plate is not covered by the eld-supplied discon-
nect switch.
• Some disconnect switches are not fused. Protect the
power leads at the point of distribuon 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 edion of the Naonal Electrical Code (AN-
SI-NFPA 70). A ground lug is provided for this purpose.
Size grounding conductor in accordance with Table 250-
95 of the Naonal Electrical Code. Do not use the ground
lug for connecng a neutral conductor.
• Connect power wiring to the middle contactor within the
main control box or power block, if equipped.
9
LOCATIONS
NOTE: Depending on the opons installed, the locaon of the
components may vary in some models.
WARNING
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.
Main power and low voltage wiring may enter the unit through
the side or through the roof curb. If connecons need to be made
through the roof curb, a through the base kit (TTBCK03) will need
to be used. Install conduit connectors at the designated entrance
locaons. External connectors must be weatherproof. All holes
in the unit base must be sealed (including those around conduit
nuts) to prevent water leakage into building. All required conduit
and ngs 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 unbal-
ance must not exceed 2%. Contact your local power company for
correcon 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 (Above Image).
NOTE: For models equipped with the DDC controls opon, refer
to the supplemental DDC literature supplied with the unit for ad-
dional informaon.
1. A 24V thermostat must be installed for unit operaon. It
may be purchased with the unit or eld -supplied. Ther-
mostats may be programmable or electromechanical as
required.
2. Locate thermostat or remote sensor in the condioned
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 instal-
laon instrucons packaged with the thermostat.
3. Use #18 AWG wire for 24V control wiring runs not ex-
ceeding 75 feet. Use #16 AWG wire for 24V control wir-
ing runs not exceeding 125 feet. Use #14 AWG wire for
24V control wiring runs not exceeding 200 feet. Low volt-
age wiring may be Naonal Electrical Code (NEC) Class 2
where permied by local codes.
10
4. Route thermostat wires from sub-base terminals to the
unit. Control wiring should enter through the duct pan-
el (dimple marks entrance locaon) or through the ap-
proved base pan locaon. 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 depend-
ing on unit/curb conguraon. Use #18 AWG solid conductor wire
whenever connecng thermostat wires to terminals on sub-base.
DO NOT use larger than #18 AWG wire. A transion to #18 AWG
wire may be required before entering thermostat sub-base.
NOTE: Refer to unit wiring diagrams for thermostat hookups.
GAS SUPPLY PIPING
WARNING
IMPORTANT NOTE: This unit is factory set to operate on natural
gas at the altudes shown on the rang plate.
WARNING
The rang plate is stamped with the model number, type of gas
and gas input rang. Make sure the unit is equipped to operate
on the type of gas available. Conversion to propane (LP) gas is
permied with the use of the factory authorized conversion kit
(see the unit Technical Manual for the appropriate kit). For High
Altude derates, refer to the latest edion of the Naonal Fuel
Gas Code NFPA 54/ANSI Z223.1.
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 ignion. In addion, gas input to the burners must
not exceed the rated input shown on the rang plate. Overring
of the unit could result in premature heat exchanger failure.
IMPORTANT NOTE: To avoid possible unsasfactory operaon or
equipment damage due to under ring of equipment, do not un-
dersize 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 rang plate is stamped with the model number, type of gas
and gas input rang. Make sure the unit is equipped to operate
on the type of gas available. The gas line installaon must comply
with local codes, or in the absence of local codes, with the latest
edion of the Naonal Fuel Gas Code NFPA 54/ANSI Z223.1.
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
Nominal Black Pipe Size (inches)
Length of
Pipe in Feet
CFH = BTUH Furnace Input
Refer to the Proper Piping Pracce drawing for the general layout
at the unit. The following rules apply:
1. Use black iron pipe and ngs for the supply piping. The
use of a ex connector and/or copper piping is permied
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 acon 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 connecon to the
gas valve to keep it from turning.
6. Install a manual shut-o valve in a convenient locaon
(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 ngs
• Semirigid metallic tubing and metallic ngs (Alu-
minum alloy tubing must not be used in exterior
locaons)
11
• Listed gas appliance connectors used in accordance
with the terms of their lisng 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 ther-
mal damage. Aluminum alloy tubing and connectors
must be coated to protect against external corrosion
when in contact with masonry, plaster or insulaon
or are subject to repeated wengs 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
NOTE: The unit gas supply entrance is factory sealed with plugs.
Keep plugs in place unl gas supply is ready to be installed. Once
ready, replace the plugs with the supplied grommets and install
gas supply line.
CAUTION
•
•
•
-
WARNING
There will be air in the gas supply line aer tesng for leaks on a
new installaon. Therefore, the air must be bled from the line by
loosening the ground joint union unl pure gas is expelled. Tight-
en union and wait for ve minutes unl 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 operaon by closing
the main electrical disconnect switch for the unit.
PROPANE GAS INSTALLATIONS
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 Naonal Board of Fire Underwriters (See NBFU Manual 58).
Line pressure 11.3 - 14” w.c.
For sasfactory operaon, 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 op-
eraon. Maintaining proper gas pressure depends on three main
factors:
1. Vaporizaon rate, which depends on (a) temperature of
the liquid, and (b) weed surface area of the container
or containers.
2. Proper pressure regulaon.
12
3. Pressure drop in lines between regulators, and between
second stage regulator and the appliance. Pipe size re-
quired will depend on length of pipe run and total load of
all appliances.
Complete informaon regarding tank sizing for vaporizaon, rec-
ommended regulator sengs and pipe sizing is available from
most regulator manufacturers and propane gas suppliers.
Since propane gas will quickly dissolve white lead or most stan-
dard com mercial compounds, special pipe dope must be used.
Shellac base compounds resistant to the acons of liqueed pe-
troleum gases such as Gasolac®, Stalacc®, Clyde’s® or John Crane®
are sasfactory.
See following gure for typical propane gas piping.
Maximum
Continuous
Second Stage
Regulator
First Stage
Regulator
TYPICAL PROPANE GAS PIPING
The gas supply piping locaon and installaon for roof top units
must be in accordance with local codes or, in the absence of locals
codes, with ordinances of the latest edion of the Naonal Fuel
Gas Code (ANSI Z223.1).
A manual gas shut o valve must be eld installed external to the
roof top unit. In addion, a drip leg must be installed near the
inlet connecon. A ground joint union connecon is required be-
tween the external shut o valve and the unit connecon 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 assem-
bly.
2. All units are furnished with standard female NPT pipe
connecons. Connecon 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 characteris-
cs, 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 edion of the
Naonal Fuel Gas Code (ANSI Z223.1).
NOTE: The gas connecon size at the unit does NOT es-
tablish the size of the supply line.
3. These units are designed for either natural or propane
(LP) gas and are specically constructed at the factory
for only natural gas fuel. The fuels are NOT interchange-
able. 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 qualied contractor, experienced with natural and pro-
pane gas systems, should aempt conversion. Kit instruc-
ons must be followed closely to assure safe and reliable
unit operaon.
4. With all units on a common line operang 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 pos-
ive shut o service pressure regulator. The unit will not
funcon sasfactorily 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 operang 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 funcon sasfactorily if supply gas
pressure is less than 11.0” w.c. or greater than 14.0” w.c.
6. All pipe connecons should be sealed with a pipe thread
compound, which is resistant to the fuel used with the
furnace. A soapy water soluon 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 connec-
on to measure supply (main) gas pressure. Another 1/8”
tap is provided on the side of the manifold for checking
manifold pressure.
WARNING
CAUTION
-
7. There must be no obstrucon to prevent the ow of com-
buson and venlang air. A vent stack is not required
and must never be used. The power ventor will supply
an adequate amount of combuson air as long as the air
passageways are kept free of any obstrucons and the
recommended external unit clearances are maintained.
CIRCULATING AIR AND FILTERS
The supply duct should be provided with an access panel large
enough to inspect the air chamber downstream of the heat ex-
changer. A cover should be ghtly aached to prevent air leaks.
Ductwork dimensions are shown in the roof curb installaon
manual.
If desired, supply and return duct connecons to the unit may be
made with exible connecons to reduce possible unit operang
sound transmission.
13
VENTING
NOTE: Venng is self-contained.
CONDENSATE DRAIN CONNECTION
A 1” female NPT drain connecon is supplied on the end of the
condensate pan, with an alternave connecon on the boom of
the pan. An external trap must be installed for proper condensate
drainage.
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 t-
ngs or larger. Do not operate without trap.
NOTE: All threaded connecon should be seal with a thread sealer.
Drainage of condensate directly onto the roof may be acceptable;
(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 con-
necon, check the drain plug in boom connecon to ensure it is
ght.
Due to the fact that drain pans in any air condioning unit will
have some moisture in them, algae and fungus will grow due to
airborne bacteria and spores. Periodic cleaning is necessary to
prevent this build-up from plugging the drain.
STARTUP, ADJUSTMENTS, AND CHECKS
WARNING
HIGH VOLTAGE
CAUTION
WARNING
MOVING MACHINERY HAZARD!
This unit is equipped with an electronic ignion device to auto-
macally light the main burners. It also has a power vent blower
to exhaust combuson products.
On new installaons, or if a major component has been replaced,
the operaon of the unit must be checked.
Check unit operaon as outlined in the following instrucons. If
any sparking, odors, or unusual sounds are encountered, shut o
electrical power and recheck for wiring errors, or obstrucons in
or near the blower motors.
The Startup, Adjustments, and Checks procedure provides a step-
by-step sequence which, if followed, will assure the proper start-
up of the equipment in the minimum amount of me. Air bal-
ancing of duct system is not considered part of this procedure.
However, it is an important phase of any air condioning system
startup and should be performed upon compleon of the Startup,
Adjustments, and Checks procedure. The Startup, Adjustments,
and Checks procedure at outside ambients below 55°F should be
limited to a readiness check of the refrigeraon system with the
required nal check and calibraon le to be completed when the
outside ambient rises above 55°F.
If the unit is to be used for temporary heang or cooling, a “Start-
up, Adjustments, and Checks” must rst be performed in accor-
dance with this manual. Damage or repairs due to failure to com-
ply with these requirements are not covered under the warranty.
Aer the machines are used for temporary heang or cooling,
inspect the coils, fans, and motors for unacceptable levels of con-
strucon dust and dirt and install new lters.
14
The installing contractor must be certain that:
• All supply and return air ductwork is in place, properly
sealed, and corresponds with installaon instrucons.
• All thermostats are mounted and wired in accordance
with installaon instrucons.
• All electric power, all gas, hot water or steam line con-
necons, and the condensate drain installaon have been
made to each unit on the job. These main supply lines
must be funconal and capable of operang all units si-
multaneously.
• Requirements are met for venng and combuson air.
• Air lters are in place.
• Input rate and temperature rise are adjusted per rang
plate.
Inspect the roof curb for correct installaon. The unit and curb as-
sembly should be level. Inspect the ashing of the roof mounng
curb to the roof, especially at the corners, for good workmanship.
Also check for leaks around gaskets. Note any deciencies in a
separate report and forward to the contractor.
Remove any extraneous construcon and shipping materials
that may be found during this procedure. Rotate all fans man-
ually to check for proper clearances and that they rotate freely.
Check for bolts and screws that may have jarred loose during
shipment to the job site. Re-ghten if necessary. Re-ghten all
electrical connecons.
Verify that all duct connecons are ght and that there is no air
bypass between supply and return.
Remove lter secon access panels and check that lters are
properly installed. Note airow arrows on lter frames.
It is important to your safety that the unit has been properly
grounded during installaon. Check ground lug connecon in
main control box for ghtness prior to closing circuit breaker or
disconnect switch. Verify that supply voltage on line side of dis-
connect agrees with voltage on unit idencaon plate and is
within the ulizaon voltage range as indicated in Appendix C
Electrical Data.
System Voltage - That nominal voltage value assigned to a circuit
or system for the purpose of designang its voltage class.
Nameplate Voltage - That voltage assigned to a piece of equip-
ment for the purpose of designang its voltage class and for the
purpose of dening the minimum and maximum voltage at which
the equipment will operate.
- The voltage of the line terminals of the
equipment at which the equipment must give fully sasfactory
performance. Once it is established that supply voltage will be
maintained within the ulizaon range under all system condi-
ons, check and calculate if an unbalanced condion exists be-
tween phases. Calculate percent voltage unbalance as follows:
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
Close the disconnect switch to energize control transformer.
Check primary and secondary (24V) of control transformer.
AIR FLOW ADJUSTMENTS
When the nal adjustments are complete, the current draw of the
motor should be checked and compared to the full load current
rang of the motor. The amperage must not exceed the service
factor stamped on the motor nameplate. The total airow must
not be less than that required for operaon of the electric heaters
or the furnace.
If an economizer is installed, check the unit operang balance
with the economizer at full outside air and at minimum outside
air.
NOTE: High Stage Airow seng below 300 CFM/Ton is not rec-
ommended, as evaporator freezing or poor unit performance is
possible.
• The unit has one set of taps for cooling (T1-T5) and a sec-
ond set of taps for heang (T6-T10).
• When Heat is called TB1-W1 will also call TB1-DH acvat-
ing the second set of taps T6-T10.
• If cooling and heang is called at the same me heang
will take priority and T6-T10 will be chosen by default.
• Taps T1 and T2 are for low cool operaon (cooling stage
1) and Taps T3 to T5 are for high cool operaon (cooling
stage 2).
• Taps T6 and T7 are for low heat operaon (heang stage
1) and taps T8 to T10 are for high heat operaon (heang
stage 2).
Taps are selected by changing the posion of the low voltage
leads on the terminal block TB1. Refer to Appendix A for blower
performance at each speed tap.
Fan speed for G (GR) is xed at TB1-T1 and cannot be moved.
Low Cool Y1, Yellow (YL) is movable and set to TB1-T1.
Low Heat W1, White (WH) is movable and set to TB1-T6.
High Cool Y2, Purple (PU) is movable and set to TB1-T3.
High Heat W2, Brown (BR) is movable and set to TB1-T8.
15
These wires can be moved together or separately and placed on
any unoccupied terminal.
NOTE: YL can be moved to tap T3 as long as YL does not share the
tap with PU. WH can be moved to tap T7 as long as WH does not
share the tap with BR.
If high cool operaon is set at Tap T4 or T5, low cool operaon
must be set at T2.
If high heat operaon is set at T9 or T10, low heat operaon must
be set at T7.
NOTE: On units with DDC controls installed, air ow adjustments
are made through sengs in the DDC controller and speed tap
adjustments are not required. Refer to the DDC User Manual for
details on making airow adjustments. Individual sengs are
available for Fan Only, Low Stage Cooling, High Stage Cooling, Low
Stage Heang, and High Stage Heang which can be adjusted as
needed to meet airow requirements.
AC G Y1 Y2 W1 W2 DH T1 T2 T3 T4 T5 T6 T7 T8 T9 T10
Fan Only X GR
Cooling Mode LO X X
Cooling Mode HI X X X
Hea�ng Mode Lo X X
Hea�ng Mode HI X X X
X= 24V Signal
DFC/DFG OPERATION and WIRE RANGE CHART
DFC/DFG OPERATION
WIRE RANGE
= Range of AVAILABLE TAPS
For wire color informa�on and placement, view DFC/DFG Model Wiring
DRC Model Wiring
GR (FAN)
Energized during Heat Mode
BR (Heating Stage 2)
PU (Cooling Stage 2)
WH (Heating Stage 1)
YL (Cooling Stage 1)
** TB1-DH is energized when the unit is in heat
mode. When TB1-DH is energized, the blower motor
operates at a new group of programmed speeds,
T6-T10, in place of T1-T5.
• Move YELLOW (YL) wire from TB1-T1 to T2 to change blower speed during cooling stage 1 operation.
(Do not move wires YL and PU to the same taps)
• Move WHITE (WH) wire from TB1-T6 to T7 to change blower speed during heating stage 1 operation.
(Do not move wires WH and BR to the same taps)
• Move PURPLE (PU) wire from TB1-T3 to T4 or T5 to change blower speed during cooling stage 2 operation.
(Do not move wires YL and PU to the same taps)
• Move BROWN (BR) wire from TB1-T8 to T9 or T10 to change blower speed during heating stage 2 operation.
(Do not move wires WH and BR to the same taps)
16
Make preliminary check of evaporator fan ampere draw and veri-
fy that motor nameplate amps are not exceeded. A nal check of
amp draw should be made upon compleon of air balancing of
the duct system (see Appendix B).
GAS SYSTEM CHECK
NOTE: For models equipped with the DDC controls opon, refer
to the supplemental DDC literature supplied with the unit for ad-
dional informaon.
1. Close the manual gas valve external to the unit.
2. Turn o the electrical power supply to the unit.
3. Set the room thermostat to its lowest possible seng.
4. Remove the heat exchanger door on the side of the unit
by removing screws.
5. This unit is equipped with an ignion device which auto-
macally lights the main burner. DO NOT try to light burn-
er by any other method.
6. Move the gas control valve switch to the OFF posion. Do
not force.
7. Wait ve minutes to clear out any gas.
8. Smell for gas, including near the ground. This is import-
ant because some types of gas are heavier than air. If you
have waited ve minutes and you do smell gas, imme-
diately 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 posion.
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 seng.
WARNING
WARNING
IMPORTANT NOTE: This unit is factory set to operate on natural
gas at the altudes shown on the rang plate.
WARNING
NOTE: Gas appliances located more than 2000 feet above sea lev-
el must be derated 4% per 1000 feet of total elevaon and that
variance in gas heang value and specic gravity require change
in manifold pressure to obtain rang, it is mandatory that the in-
put be adjusted at the installaon site. All installaons should be
made as outlined.
NOTE: Except during brief periods when gas pressures are being
measured by qualied service personnel, the furnace access pan-
el must always be secured in place when the furnace is in opera-
on. An inspecon 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 ghtness and purge the system
of air using methods outlined in the latest edion of the Naon-
al Fuel Gas Code ANSI Z223.1. Verify that the disconnect switch
is in the “OFF” posion. A soapy water soluon 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
connecons and joints be tested for ghtness. Gas piping down-
stream 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 nat-
ural gas and 11.0” on LP gas with the gas burners operang. 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 rang, gas sup-
ply 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 aempt adjustment of the built-in pressure regulator unless
the supply pressure is at least 7.0” w.c. on natural gas or 14.0” w.c.
on propane gas. Check the locaon of the ignion electrode and
the ame sensor for correct gap seng. (See Figure below)
Flame
Sensor
Ignitor
17
NATURAL
350,000 750,000 #30 #48
400,000 850,000 #30 #48
GAS ORIFICES
MAXIMUM
INPUT
NUMBER
of
BURNERS
MAXIMUM
BTUH/BURNER
HEAT EXCHANGER AND BURNER ORIFICE SPECIFICATIONS
NOTE: Gas appliances located more than 2000 feet above sea lev-
el must be derated 4% per 1000 feet of total elevaon and that
variance in gas heang value and specic gravity require change
in manifold pressure to obtain rang, it is mandatory that the in-
put be adjusted at the installaon site. All installaons should be
made as outlined in the latest edion of the Naonal Fuel Gas
Code ANSI Z223.1, secon “Procedures To Be Followed To Place
An Appliance in Operaon”. Refer also to the “User’s Informaon
Manual” supplied with the unit for addional informaon on the
gas furnace.
Gas supply pressure and manifold pressure with the burners oper-
ang must be as specied on the rang plate.
Gas inlet pressure must be checked and adjusted in accordance to
the type of fuel being consumed.
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 ng.
2. Put unit into heang cycle and turn on all other gas con-
suming 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 operang pressures dier from above, make necessary pressure
regulator adjustments, check piping size, etc., and/or consult with
local ulity.
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 mea-
surement. The manifold pressure must be measured with the
burners operang.
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 vari-
aons in gas ow should be made by means of the pressure reg-
ulator adjustment. In no case should the nal manifold pressure
vary more than plus or minus 0.3 inches water column from the
specied nominal pressure. Any major changes in ow should be
made by changing the size of the burner orices. The measured
input rate to the furnace must not exceed the rang specied on
the unit rang 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.
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 o gas supply to all other appliances except the unit.
2. With the unit operang, me the smallest dial on the me-
ter for one complete revoluon. 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 heang 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 rang plate.
Adjust input rate by varying the adjustment of the gas pressure
regulator on the gas valve. All adjustments must be made with
furnace operang at high re and at normal operang tempera-
ture. A manometer should be connected to the gas valve to ver-
ify pressure is within the specied range (see following gures
for manometer connecons). Clockwise rotaon of the pressure
regulator screw increases pressure and gas ow rate. Turn screw
counterclockwise to decrease pressure and gas ow rate. Aer ad-
justment the furnace temperature rise must be within the range
specied on the unit data plate. NOTE: Thermal eciency of the
furnace is a product eciency rang determined under conn-
uous operang condions 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
18
Manometer
Manometer
Hose
High Fire Regulator
Adjust Regulator
Vent
On/Off Switch
HighFire Coil
Terminal (HI) Coaxial Coil
Terminal (M)
Common
Terminal(C)
White-Rodgers Model 36J54 Connected to Manometer
Mode
3.5
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. Aach a hose and manometer to the outlet pressure boss
of the valve. (See image above)
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 detecon soluon or soap suds, check for
leaks at pressure boss screw. Bubbles forming indicate a
leak. SHUT OFF GAS AND FIX ALL LEAKS IMMEDIATELY.
CAUTION
6. Relight all other appliances turned o in step 1. Be sure
all pilot burners are operang.
Flames should be stable, so and blue (dust may cause orange
ps but they must not be yellow) and extending directly outward
from the burner without curling, oang or liing o.
Check the temperature rise through the unit by placing thermom-
eters in supply and return air registers as close to the unit as pos-
sible. 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 parally open) posion and the unit op-
erated for 15 minutes on HIGH FIRE before taking readings.
2. The temperature rise must be within the range specied
on the rang plate.
NOTE: Air temperature rise is the temperature dierence be-
tween supply and return air.
With a properly designed system, the proper amount of tempera-
ture 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 in-
crease the temperature rise.
NOTE: Blower speed MUST be set to give the correct air tempera-
ture rise through the unit as marked on the rang plate.
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 aempt igni-
on, check if the ALS (Automac Reset High Limit Control Switch)
requires reseng.
1. With electricity and gas turned on, the system switch in
the “HEAT” or “AUTO” posion and the fan switch in the
“AUTO” posion, the thermostat will close the circuit be-
tween unit terminals R and W (R-W) when the tempera-
ture falls below the thermostat seng.
2. D1 on IIC energizes relay VMR.
3. Relay VMR energizes the vent motor.
4. Operaon of the vent motor closes the pressure switch
PS located in the burner compartment. The control then
iniates a 15-second pre-purge me delay. During this
period, the vent motor will clear the combuson cham-
ber of any residual gas.
5. Aer the pre-purge period, the ignion control energizes
the Wl-C gas valve and simultaneously iniates a “three
(3)-try” spark ignion sequence.
6. When the burners are ignited, a minimum four (4) mi-
cro-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 es-
tablished, it will keep the gas valve energized and discon-
nue the ignion 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 aer its inial
aempt, it will iniate another purge and spark sequence.
A third purge and spark sequence will be iniated if the
second aempt is unsuccessful. If the third aempt is un-
successful, the controller will close the gas valve and lock
itself out. It may be reset by momentarily interrupng
power. This may be accomplished by briey lowering the
room thermostat set-point below room temperature, or
by shung o the main power to the unit. (See TP-105
for more details.)
19
9. Integrated ignion control will close its normally open
contacts aer a delay of approximately 30 seconds. This
acon energizes contactor BC and starts the supply fan
motor. Operaon of the supply fan circulates air across
the heat exchanger and delivers heated air to the condi-
oned 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.
1. Set the thermostat to lowest seng.
2. Turn o 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 posion. Do
not force.
5. Close manual gas shut o valve external to the unit.
6. Replace the heat exchanger door on the unit.
7. If cooling and/or air circulaon will be desired, turn ON
the electrical power.
Located in the burner compartment on the heat exchanger, its
sensing element projects through the blower secon bulkhead
and senses the temperature at the rear of the furnace. It will cycle
the furnace o if the temperature exceeds 100°F plus maximum
rise.
Located in the blower compartment on the blower housing, it
senses air temperature within the blower compartment and pro-
tects the lters from excessive temperature. It will shut down the
furnace if it senses excessive temperatures.
Elevated temperatures at the control are normally caused by
blower failure. The reason for the opening should be determined
and repaired prior to reseng.
Located in the burner compartment at the top of the burner as-
sembly, it senses high temperature that could occur if the heat
exchanger tubes were plugged and the ame was rolling out in-
stead of entering the tubes. It has a manual push-buon reset
that cannot be actuated unl the limit control has cooled.
The reason for elevated temperatures at the control should be
determined and repaired prior to reseng this manual reset
control.
WARNING
The unit is equipped with a thermal expansion valve as a metering
device.
Ensure the hold-down bolts on the compressor are secure and
have not vibrated loose during shipment. Check that vibraon
grommets have been installed. Visually check all piping for dam-
age and leaks; repair if necessary. The enre system has been fac-
tory charged and tested, making it unnecessary to eld charge.
Factory charges are shown on the unit’s nameplate. To conrm
charge levels or, if a leak occurs and charge needs to be added
to the system, it is recommended to evacuate the system and re-
charge refrigerant to unit nameplate specicaons.
This unit has been rated in the cooling mode at the AHRI rated
condions of: Indoor (80°db / 67°wb) and outdoor (95°db).
While operang at this condion, the superheat and subcool for
each circuit for each unit should fall within the values listed in
the table below. The superheat is measured at the sucon service
port located near the compressor. The subcool is measured at the
liquid line service port.
SUPERHEAT AND SUBCOOLING
NOTE: Units with a TXV should be charged to Subcooling only.
Make sure the air ow is correct before making any adjustments.
EXAMPLE:
a. Liquid Line Pressure = 417 PSI
b. Corresponding Temp. = 120°F
c. Thermometer on Liquid line = 109°F.
To obtain the amount of subcooling, subtract 109°F from 120°F.
The dierence is 11° subcooling. See the specicaon sheet or
technical informaon manual for the design subcooling range for
your unit.
SUBCOOLING FORMULA = SATURATED LIQUID LINE TEMPERA-
TURE - LIQUID LINE TEMPERATURE
EXAMPLE:
a. Sucon Pressure = 143 PSI
b. Corresponding Temp. = 50°F
c. Thermometer on Sucon Line = 59°F
To obtain the degrees temperature of superheat, subtract 50.0
from 59.0°F. The dierence is 9° Superheat. The 9° Superheat
would fall in the ± range of allowable superheat.
20
SUPERHEAT = SUCTION LINE TEMP - SAT. SUCTION TEMP.
NOTE: Superheat adjustments should not be made unl indoor
ambient condions have stabilized. This could take up to 24 hours
depending on indoor temperature and humidity. Before check-
ing superheat, run the unit in cooling for 15-20 minutes or unl
refrigerant pressures stabilize. Use the following guidelines and
methods to check unit operaon and ensure that the refrigerant
charge is within limits.
For TXV systems, to adjust superheat, unscrew the cover from the
expansion valve, locate the adjustment screw, and turn it clock-
wise (in) to increase superheat or counterclockwise (out) to de-
crease superheat. It is recommended to make small adjustments
at a me, 1/8-1/4 turn increments. Replace adjustment cap. Wait
a minimum of 15 minutes between adjustments to allow me for
the TXV and pressures to stabilize.
NOTE: For opmal performance, follow charging instrucons
below.
Units with Fixed Orice Devices
All package units with xed orice devices are charged using the
superheat method at the compressor sucon line. To increase su-
per heat, remove charge and to decrease super heat, add charge.
Aer superheat is adjusted, it is recommended to check unit sub-
cooling at the condenser coil liquid line. See Figure 14: DESIGN
SUPERHEAT AND SUBCOOLING table for targets on each model.
Single Stage Cooling Applicaon: Refer to the Design Superheat &
Subcooling table.
Two-Stage Cooling Applicaon: Run unit on Low Stage cooling and
refer to Design Superheat & Subcooling table.
1. Purge gauge lines. Connect service gauge manifold to
access ngs. Run system at least 10 minutes to allow
pressure to stabilize.
2. Temporarily install thermometer on liquid (small) line
near liquid line access ng with adequate contact and
insulate for best possible reading.
3. Check subcooling and superheat. System should have a
subcooling and superheat within the range listed on the
Design Superheat and Subcooling table.
a. If subcooling and superheat are low, adjust TXV su-
perheat, then check subcooling.
NOTE: To adjust superheat, turn the valve stem clock-
wise to increase and counterclockwise to decrease.
b. If subcooling is low and superheat is high, add charge
to raise subcooling then check superheat.
c. If subcooling and superheat are high, adjust TXV
valve superheat, then check subcooling.
d. If subcooling is high and superheat is low, adjust TXV
valve superheat and remove charge to lower the sub-
cooling.
NOTE: Do NOT adjust the charge based on sucon
pressure unless there is a gross undercharge. If
an under charge is suspected recover the charge,
re-evacuate the system and recharge per data plate.
No adjustments should be made if suspecng a
charge issue.
5. Disconnect manifold set, installaon is complete.
Design Superheat & Subcooling
Model Circuit Superheat
± 20F
Subcooling
0F
Expan-
sion
Device
Outdoor
Ambient
DFG180 18 14 TXV 95
DFG180 2812 TXV 95
DFG240 189TXV 95
DFG240 28 6 TXV 95
DFG300 1 10 7 TXV 95
DFG300 2 10 7 TXV 95
Begin with power turned on at all disconnects.
1. Ensure the thermostat is set to OFF and Fan is set to Auto.
On units with DDC controls installed, use Test/ Balance
Menu to force the unit to O Mode.
2. Inspect all registers and set them to the normal open
posion.
3. Turn on the electrical supply at the disconnect.
4. Turn the fan switch to the “ON” posion. The blower
should operate aer a 7 second delay. On units with DDC
controls installed, use Test/Balance Menu to force the
unit to Vent Mode. This test bypasses internal delays.
5. Turn the fan switch to “Auto” posion. The blower should
stop aer a 65 second delay. On units with DDC controls
installed, use Test/Balance Menu to force the unit to O
Mode. This test bypasses internal delays.
6. Set the thermostat to Cool mode and lower the cooling
unl the unit is running both stage of cooling. The com-
pressors, blowers, and condenser fans should now be op-
erang. Allow the unit to run 10 minutes, make sure cool
air is being supplied by the unit. On units with DDC con-
trols installed, use Test/Balance Menu to force the unit to
High Cool Mode. This test bypasses internal delays.
7. Check that both compressors are operang correctly. The
scroll compressors in these units MUST operate in the
proper rotaon. To ensure the compressors are operang
in the correct direcon, check that the temperature of
the compressor discharge line increases when the com-
pressor turns on. If this does not occur and the compres-
sor is producing an exceponal amount of noise, this indi-
cates that there is a phasing issue. Perform the following
to correct:
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