Carrier Performance 48VGUK User manual

Installation Instructions
IMPORTANT: Effective January 1, 2015, all split system and packaged
air conditioners must be installed pursuant to applicable regional
efficiency standards issued by the Department of Energy.
NOTE: Read the entire instruction manual before starting the
installation.
NOTE: Installer: Make sure the Owner’s Manual and Service
Instructions are left with the unit after installation.
Table of Contents
Table of Contents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Safety Considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Receiving and Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Identify Unit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Inspect Shipment. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Roof Curb . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Slab Mount . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Inspection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Rigging/Lifting of Unit (See Fig. 6) . . . . . . . . . . . . . . . . . . . . . . 4
Configuring Units for Downflow (Vertical) Discharge . . . . . . 11
High-Voltage Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Special Procedures for 208-v Operation. . . . . . . . . . . . . . . . . . 13
Control Voltage Connections . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Standard Connection. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Heat Anticipator Setting (Electro-Mechanical Thermostats only)14
Transformer Protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Pre-Start-up. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Start-up . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Check Heating Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Check Gas Input . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Adjust Gas Input . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Normal Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
Airflow and Temperature Rise . . . . . . . . . . . . . . . . . . . . . . . . . 22
Heating Sequence of Operation (Ultra Low NOx Single and Three
Phase Models). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
Limit Switches . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
Burner Thermal Switch (Ultra Low NOx) . . . . . . . . . . . . . . . . 22
Checking Cooling Control Operation . . . . . . . . . . . . . . . . . . . . 22
Checking and Adjusting Refrigerant Charge . . . . . . . . . . . . . . 23
Indoor Airflow and Airflow Adjustments . . . . . . . . . . . . . . . . 23
Cooling Sequence of Operation . . . . . . . . . . . . . . . . . . . . . . . . 24
Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
Air Filter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
Indoor Blower and Motor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
Induced Draft (combustion air) Blower Assembly. . . . . . . . . . 37
Flue Gas Passageways . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
Limit Switch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
Burner Ignition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
Ultra Low NOx Burner Baffle Inspection/Cleaning (See Fig. 21.)
38
Outdoor Coil, Indoor Coil, and Condensate Drain Pan . . . . . . 39
Outdoor Fan . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
Electrical Controls and Wiring . . . . . . . . . . . . . . . . . . . . . . . . . 39
Refrigerant Circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
Gas Input. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
Evaporator Airflow. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
Puron (R-410A) Items . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
Metering Device (Thermostatic Expansion Valve ) . . . . . . . . . 40
Pressure Switches . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
Loss of Charge Switch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
High-Pressure Switch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
Copeland Scroll Compressor (Puron [R-410A] Refrigerant) . . 40
Refrigerant System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
Start-up Checklist . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
A09033
Fig. 1 – Unit 48VG Ultra Low NOx
Safety Considerations
Improper installation, adjustment, alteration, service maintenance, or use
can cause explosion, fire, electrical shock, or other conditions which
may cause death, personal injury, or property damage. Consult a
qualified installer, service agency, or your distributor or branch for
information or assistance. The qualified installer or agency must use
factory-authorized kits or accessories when modifying this product.
Refer to the individual instructions packaged with the kits or accessories
when installing.
Follow all safety codes. Wear safety glasses, protective clothing, and
work gloves. Have a fire extinguisher available. Read these instructions
thoroughly and follow all warnings or cautions included in literature and
attached to the unit. consult local building codes, the current editions of
the National Fuel Gas Code (NFGC) NFPA 54/ANSI Z223.1, and the
National Electrical Code (NEC) NFPA 70.
48VGUK
Performance™ 15.2+ SEER2 Ultra Low NOx 2-Stage
Packaged Air Conditioner and Single Stage Gas
Furnace System with Puron® (R-410A) Refrigerant
Single and Three Phase
2-5 Nominal Tons (Sizes 24-60)

48VGUK: Installation Instructions
Manufacturer reserves the right to change, at any time, specifications and designs without notice and without obligations.
2
In Canada refer to the current editions of the National Standards of
Canada CAN/CSA-B149.1 and .2 Natural Gas and Propane Installation
codes, and Canadian Electrical Code CSA C22.1
Recognize safety information. This is the safety-alert symbol . When
you see this symbol on the unit and in instructions or manuals, be alert to
the potential for personal injury. Understand these signal words:
DANGER, WARNING, and CAUTION. These words are used with the
safety-alert symbol. DANGER identifies the most serious hazards which
will result in severe personal injury or death. WARNING signifies
hazards which could result in personal injury or death. CAUTION is
used to identify unsafe practices which may result in minor personal
injury or product and property damage. NOTE is used to highlight
suggestions which will result in enhanced installation, reliability, or
operation.
Most states is the USA and jurisdictions in Canada have laws that
require the use of Carbon Monoxide (CO) alarms with fuel burning
products. Examples of fuel burning products are furnaces, boilers, space
heaters, generators, water heaters, stoves/ranges, clothes dryers,
fireplaces, incinerators, automobiles, and other internal combustion
engines. Even if there are no laws in your jurisdiction requiring a CO
Alarm, it’s highly recommended that whenever any fuel burning product
is used in or around the home or business that the dwelling be equipped
with a CO Alarm(s). The Consumer Product Safety Commission
recommends the use of CO Alarm(s). The CO Alarm(s) must be
installed, operated, and maintained according to the CO Alarm
manufacturer’s instructions. For more information about Carbon
Monoxide, local laws, or to purchase a CO Alarm only, please visit the
following website https://www.kidde.com
Introduction
This unit (see Fig. 1) is a fully self-contained, combination Category I
gas heating/electric cooling unit designed for outdoor installation (See
Fig. 3 and Fig. 4 for unit dimensions). All unit sizes have return and
discharge openings for both horizontal and downflow configurations,
and are factory shipped with all downflow duct openings covered. Units
may be installed either on a rooftop or on a cement slab. (See Fig. 5 for
roof curb dimensions).
In gas heating mode, this unit is designed for a minimum continuous
return-air temperature of 55°F (13°C) db and a maximum continuous
return-air temperature of 80°F (27°C) db. Failure to follow these
return-air temperature limits may affect reliability of heat exchangers,
motors, and other components.
Models with a “U” in the fifth position of the model number are
dedicated to the Ultra Low NOx emissions requirements of 14
nonograms/joule and must be installed in California Air Quality
Management Districts or any other regions in North America where
Ultra Low NOx rules exist.
WARNING
!
CARBON MONOXIDE POISONING HAZARD
Failure to follow this warning could result in personal injury and/or
death.
Carbon Monoxide (CO) is a colorless, odorless, and tasteless poisonous
gas that can be fatal when inhaled. Follow all installation, maintenance,
and service instructions. See additional information below regarding
the installation of a CO Alarm.
WARNING
!
ELECTRICAL SHOCK HAZARD
Failure to follow this warning could result in personal injury or death.
Before installing or servicing system, always turn off main power to
system and install lockout tag. There may be more than one disconnect
switch. Turn off accessory heater power switch if applicable.
WARNING
!
PERSONAL INJURY AND ENVIRONMENTAL HAZARD
Failure to relieve system pressure could result in personal injury and/or
death.
1. Relieve pressure and recover all refrigerant before servicing
existing equipment, and before final unit disposal. Use all
service ports and open all flow-control devices, including
solenoid valves.
2. Federal regulations require that you do not vent refrigerant into
the atmosphere. Recover during system repair or final unit
disposal.
CAUTION
!
FIRE, EXPLOSION, ELECTRICAL SHOCK AND
CARBON MONOXIDE POISONING HAZARD
Failure to follow this warning could result in personal injury or unit
damage.
A qualified installer or agency must use only factory-authorized kits or
accessories when modifying this product.
CAUTION
!
CUT HAZARD
Failure to follow this caution may result in personal injury.
When removing access panels (see Fig. 22) or performing maintenance
functions inside your unit, be aware of sharp sheet metal parts and
screws. Although special care is taken to reduce sharp edges to a
minimum, be extremely careful and wear appropriate protective
clothing, safety glasses and gloves when handling parts or reaching into
the unit.
WARNING
!
PERSONAL INJURY AND PROPERTY DAMAGE
HAZARD
For continued performance, reliability, and safety, the only approved
accessories and replacement parts are those specified by the equipment
manufacturer. The use of non-manufacturer approved parts and
accessories could invalidate the equipment limited warranty and result
in fire risk, equipment malfunction, and failure. Please review
manufacturer's instructions and replacement part catalogs available
from your equipment supplier.
NOTICE
!
If the unit gasketing or insulation must be replaced, ensure the material
used is compliant with the two agency requirements listed.
1. Insulation and adhesives shall meet NFPA 90.1 requirements for
flame spread and smoke generation.
2. Cabinet insulation shall meet ASHRAE Standard 62.2.

48VGUK: Installation Instructions
Manufacturer reserves the right to change, at any time, specifications and designs without notice and without obligations.
3
Receiving and Installation
Step 1 – Check Equipment
Identify Unit
The unit model number and serial number are stamped on the unit
information plate. Check this information against shipping papers.
Inspect Shipment
Inspect for shipping damage before removing packaging materials. If
unit appears to be damaged or is torn loose from its anchorage, have it
examined by transportation inspectors before removal. Forward claim
papers directly to transportation company. Manufacturer is not
responsible for any damage incurred in transit. Check all items against
shipping list. Immediately notify the nearest equipment distribution
office if any item is missing. To prevent loss or damage, leave all parts in
original packages until installation.
If the unit is to be mounted on a curb in a downflow application, review
Step 9 to determine which method is to be used to remove the downflow
panels before rigging and lifting into place. The panel removal process
may require the unit to be on the ground.
Step 2 – Provide Unit Support
For hurricane tie downs, contact distributor for details and PE
(Professional Engineering) Certificate if required.
Roof Curb
Install accessory roof curb in accordance with instructions shipped with
curb (See Fig. 5). Install insulation, cant strips, roofing, and flashing.
Ductwork must be attached to curb.
IMPORTANT: The gasketing of the unit to the roof curb is critical for a
water tight seal. Install gasketing material supplied with the roof curb.
Improperly applied gasketing also can result in air leaks and poor unit
performance.
Curb should be level to within 1/4 in. (6 mm). This is necessary for unit
drain to function properly. Refer to accessory roof curb installation
instructions for additional information as required.
Installation on older “G” series roof curbs.
Two accessory kits are available to aid in installing a new “G” series unit
on an old “G” roof curb.
1. Accessory kit number CPADCURB001A00, (small chassis) and
accessory kit number CPADCURB002A00, (large chassis) includes
roof curb adapter and gaskets for the perimeter seal and duct
openings. No additional modifications to the curb are required
when using this kit.
2. An alternative to the adapter curb is to modify the existing curb by
removing the outer horizontal flange and use accessory kit number
CPGSKTKIT001A00 which includes spacer blocks (for easy
alignment to existing curb) and gaskets for the perimeter seal and
duct openings. This kit is used when existing curb is modified by
removing outer horizontal flange.
Slab Mount
Place the unit on a solid, level pad that is at least 2 in. (51 mm) above
grade. The pad should extend approximately 2 in. (51 mm) beyond the
casing on all 4 sides of the unit. (See Fig. 2.) Do not secure the unit to
the pad except when required by local codes.
A07926
Fig. 2 – Slab Mounting Details
Step 3 – Field Fabricate Ductwork
Secure all ducts to roof curb and building structure on vertical discharge
units. Do not connect ductwork to unit. For horizontal applications, unit
is provided with flanges on the horizontal openings. All ductwork should
be secured to the flanges. Insulate and weatherproof all external
ductwork, joints, and roof openings with counter flashing and mastic in
accordance with applicable codes.
Ducts passing through an unconditioned space must be insulated and
covered with a vapor barrier.
If a plenum return is used on a vertical unit, the return should be ducted
through the roof deck to comply with applicable fire codes.
Read unit rating plate for any required clearances around ductwork.
Cabinet return-air static shall not exceed -.25 IN. W.C.
Step 4 – Provide Clearances
IMPORTANT: The unit must be secured to the curb by installing
screws through the bottom of the curb flange and into the unit base rails.
When installing large base units onto the common curb, the screws must
be installed before allowing the full weight of the unit to rest on the curb.
A minimum of six screws are required for large base units. Failure to
secure unit properly could result in an unstable unit. See Warning near
Rigging/Lifting information and accessory curb instructions for more
details.
The required minimum operating and service clearances are shown in
Fig. 3 and Fig. 4. Adequate combustion, ventilation and condenser air
must be provided.
IMPORTANT: Do not restrict outdoor airflow. An air restriction at
either the outdoor-air inlet or the fan discharge may be detrimental to
compressor life.
The outdoor fan pulls air through the outdoor coil and discharges it
through the top grille. Be sure that the fan discharge does not recirculate
to the outdoor coil. Do not locate the unit in either a corner or under an
overhead obstruction. The minimum clearance under a partial overhang
(such as a normal house overhang) is 48-in. (1219 mm) above the unit
top. The maximum horizontal extension of a partial overhang must not
exceed 48-in. (1219 mm).
Do not place the unit where water, ice, or snow from an overhang or roof
will damage or flood the unit. Do not install the unit on carpeting or
other combustible materials. Slab-mounted units should be at least 2 in.
(51 mm) above the highest expected water and runoff levels. Do not use
unit if it has been under water.
Step 5 – Rig and Place Unit
CAUTION
!
UNITS/STRUCTURAL DAMAGE HAZARD
Failure to follow this caution may result in property damage.
Ensure there is sufficient clearance for saw blade when cutting the outer
horizontal flange of the roof curb so there is no damage to the roof or
flashing.
OPTIONAL
RETURN
AIR
OPENING
OPTIONAL
SUPPLY
AIR
OPENING
EVAP. COIL COND. COIL
ß
(50.8mm)

48VGUK: Installation Instructions
Manufacturer reserves the right to change, at any time, specifications and designs without notice and without obligations.
4
Rigging and handling of this equipment can be hazardous for many
reasons due to the installation location (roofs, elevated structures, etc.).
Only trained, qualified crane operators and ground support staff should
handle and install this equipment.
When working with this equipment, observe precautions in the literature,
on tags, stickers, and labels attached to the equipment, and any other
safety precautions that might apply.
Training for operators of the lifting equipment should include, but not be
limited to, the following:
1. Application of the lifter to the load, and adjustment of the lifts to
adapt to various sizes or kinds of loads.
2. Instruction in any special operation or precaution.
3. Condition of the load as it relates to operation of the lifting kit, such
as balance, temperature, etc.
Follow all applicable safety codes. Wear safety shoes and work gloves.
Inspection
Prior to initial use, and at monthly intervals, all rigging shackles, clevis
pins, and straps should be visually inspected for any damage, evidence
of wear, structural deformation, or cracks. Particular attention should be
paid to excessive wear at hoist hooking points and load support areas.
Materials showing any kind of wear in these areas must not be used and
should be discarded.
Rigging/Lifting of Unit (See Fig. 6)
Lifting holes are provided in base rails as shown in Fig. 3 and Fig. 4.
1. Leave top shipping skid on the unit for use as a spreader bar to
prevent the rigging straps from damaging the unit. If the skid is not
available, use a spreader bar of sufficient length to protect the unit
from damage.
2. Attach shackles, clevis pins, and straps to the base rails of the unit.
Be sure materials are rated to hold the weight of the unit (See
Fig. 6).
3. Attach a clevis of sufficient strength in the middle of the straps.
Adjust the clevis location to ensure unit is lifted level with the
ground.
After the unit is placed on the roof curb or mounting pad, remove the top
skid.
WARNING
!
PERSONAL INJURY OR PROPERTY DAMAGE
HAZARD
Failure to follow this warning could result in personal injury, death or
property damage.
When installing the unit on a rooftop, be sure the roof will support the
additional weight.
WARNING
!
UNIT FALLING HAZARD
Failure to follow this warning could result in personal injury or death.
Never stand beneath rigged units or lift over people.
WARNING
!
PROPERTY DAMAGE HAZARD
Failure to follow this warning could result in personal injury/death or
property damage.
When straps are taut, the clevis should be a minimum of 36 in. (914
mm) above the unit top cover.
WARNING
!
UNIT FALLING HAZARD
Failure to follow this warning could result in personal injury or death.
Large base units must be secured to common curb before allowing full
weight of unit to rest on curb. Install screws through curb into unit base
rails while rigging crane is still supporting unit.

48VGUK: Installation Instructions
Manufacturer reserves the right to change, at any time, specifications and designs without notice and without obligations.
5
A230027
Fig. 3 – 24-30 Unit Dimensions

48VGUK: Installation Instructions
Manufacturer reserves the right to change, at any time, specifications and designs without notice and without obligations.
6
A230028
Fig. 4 – 36-60 Unit Dimensions

48VGUK: Installation Instructions
Manufacturer reserves the right to change, at any time, specifications and designs without notice and without obligations.
7
A180216
* Part Numbers CPRCURB011B00 can be used on both small and large basepan units. The cross supports must be located based on whether the unit is a small basepan or a large
basepan.
NOTES:
1 . Roof curb must be set up for unit being installed.
2. Seal strip must be applied, as required, to unit being installed.
3. Roof curb is made of 16-gauge steel.
4. Attach ductwork to curb (flanges of duct rest on curb).
5. Insulated panels: 1-in. (25.4 mm) thick fiberglass 1 lb. density.
Fig. 5 – Roof Curb Dimensions
UNIT
SIZE
CATALOG
NUMBER
A
IN.
(mm)
B (small / common
base)
IN. (mm)*
B (large base)
IN. (mm)*
C
IN.
(mm)
D
IN.
(mm)
E
IN.
(mm)
F
IN.
(mm)
G
IN. (mm)
H
IN. (mm)
Small
or
Large
CPRFCURB011B00 14
(356) 10 (254)
14 (356) 16
(406)
47.8
(1214)
32.4
(822) 2.7 (69)
30.6 (778)
46.1 (1170)
Large CPRFCURB013B00 14
(356) 14 (356) 43.9 (1116) 42.2 (1072)
RETURN
AIR
SMALL
BASE
UNIT
SUPPLY
AIR
LARGE
BASE
UNIT
UNIT PLACEMENT ON
COMMON CURB
SMALL/COMMON CURB
SMALL OR LARGE BASE UNIT
LARGE CURB

48VGUK: Installation Instructions
Manufacturer reserves the right to change, at any time, specifications and designs without notice and without obligations.
8
A09051
NOTE: See dimensional drawing for corner weights.
Fig. 6 – Suggested Rigging
Standard Copper Tube Aluminum Fin
SMALL CABINET LARGE CABINET
Unit 24 Unit 36 48 60
lb kg lb kg lb kg lb kg
Rigging
Weight 352 160 Rigging Weight 455 206 500 227 520 236
ACCESS PANELS MUST BE IN PLACE WHEN RIGGING.
PANNEAUX D'ACCES DOIT ÊTRE EN PLACE POUR MANIPULATION.
50CY502286 2.0
CAUTION - NOTICE TO RIGGERS
PRUDENCE - AVIS AUX MANIPULATEUR
Use top skid as spreader bar. / Utiliser la palette du haut comme barre de répartition
SEAL STRIP MUST BE IN
PLACE BEFORE PLACING
UNIT ON ROOF CURB
DUCTS
DETAIL A
VOIR DÉTAIL A
MINIMUM HEIGHT: 36" (914.4 mm)
HAUTEUR MINIMUM
UNIT HEIGHT
HAUTEUR D'UNITÉ
SEE DETAIL A
VOIR DÉTAIL A
BANDE SCELLANT DOIT ÊTRE
EN PLACE AVANT DE PLACER
L'UNITÉ SUR LA BASE DE TOIT

48VGUK: Installation Instructions
Manufacturer reserves the right to change, at any time, specifications and designs without notice and without obligations.
9
Table 1 – Physical Data
UNIT SIZE 24040 24060 36060 48090 60090
NOMINAL CAPACITY (ton) 2 2 3 4 5
SHIPPING WEIGHT lb.
SHIPPING WEIGHT (kg)
352
160
352
160
455
206
500
227
520
236
COMPRESSORS
Quantity
Scroll l
1
REFRIGERANT (R-410A)
Quantity lb.
Quantity (kg)
7.05
3.2
7.05
3.2
8.1
3.7
10.8
4.9
12.1
5.5
REFRIGERANT METERING DEVICE TXV
OUTDOOR COIL
Rows...Fins/in.
Face Area (sq ft)
1..21
13.6
1...21
13.6
2...21
13.6
2...21
19.4
2...21
21.4
OUTDOOR FAN
Nominal CFM
Diameter in.
Diameter (mm)
Motor Hp (Rpm)
2500
24
609.6
1/12 (810)
2500
24
609.6
1/12 (810)
3000
26
600.4
1/5 (810)
3300
26
660.4
1/5 (810)
3600
26
660.4
1/5 (810)
INDOOR COIL
Rows...Fins/in.
Face Area (sq ft)
3...17
3.7
3...17
3.7
3...17
4.7
3...17
5.7
3...17
5.7
INDOOR BLOWER
Nominal Low Stage Cooling Airflow (Cfm)
Nominal High Stage Cooling Airflow (Cfm)
Size in.
Size (mm.)
Motor HP (RPM)
600
800
10x10
254x254
1/2 (1050)
600
800
10x10
254x254
1/2 (1050)
900
1200
11x10
279.4x254
3/4 (1000)
1200
1600
11x10
279.4x254
1.0 (1075)
1200
1750
11x10
279.4x254
1.0 (1075)
FURNACE SECTION*
Burner Orifice No. (Qty...Drill Size)
Natural Gas (Factory Installed)
*. *Based on altitude of 0 to 2000 ft (0-610 m).
1...0.125 1...#28 1...#28 1...#18 1...#18
HIGH-PRESSURE SWITCH
(psig) Cut-out Reset (Auto)
650 +/- 15
420 +/- 25
LOSS-OF-CHARGE / LOW-PRESSURE SWITCH (Liquid Line)
(psig) cut-out Reset (auto)
50 +/- 7
95 +/- 7
RETURN-AIR FILTERS†
Throwaway Size in.
(mm)
†. { Required filter sizes shown are based on the larger of the AHRI (Air Conditioning Heating and Refrigeration Institute) rated cooling airflow or the heating airflow velocity of
300 ft/minute for throwaway type. Air filter pressure drop for non-standard filters must not exceed 0.08 IN. W.C.
If using accessory filter rack refer to the filter rack installation instructions for correct filter sizes and quantity.
20x20x1
508x508x25
20x24x1
508x610x25
24x30x1
610x762x25
24x36x1
610x914x25

48VGUK: Installation Instructions
Manufacturer reserves the right to change, at any time, specifications and designs without notice and without obligations.
10
Step 6 – Connect Condensate Drain
NOTE: When installing condensate drain connection be sure to comply
with local codes and restrictions.
This unit disposes of condensate water through a 3/4 in. NPT fitting
which exits through the base on the evaporator coil access side. See
Fig. 3 and Fig. 4 for location.
Condensate water can be drained directly onto the roof in rooftop
installations (where permitted) or onto a gravel apron in ground level
installations. Install a field-supplied 2-in. (51 mm) condensate trap at the
end of condensate connection to ensure proper drainage. Make sure that
the outlet of the trap is at least 1 in. (25 mm) lower than the drain-pan
condensate connection to prevent the pan from overflowing (See Fig. 7).
Prime the trap with water. When using a gravel apron, make sure it
slopes away from the unit.
A09052
Fig. 7 – Condensate Trap
Connect a drain tube using a minimum of 3/4-in. PVC or 3/4-in. copper
pipe (all field-supplied) at the outlet end of the 2-in. (51 mm) trap. Do
not undersize the tube. Pitch the drain tube downward at a slope of at
least 1-in. (25 mm) for every 10 ft (3.1 m) of horizontal run. Be sure to
check the drain tube for leaks.
Step 7 – Install Flue Hood
The flue assembly is secured and shipped in the return air duct. Remove
duct cover to locate the assembly (See Fig. 9).
NOTE: Dedicated Ultra Low NOx models MUST be installed in
California Air Quality Management Districts where an Ultra Low NOx
rule exists.
These models meet California air management districts' emissions
requirements of 14 nanograms/Joule of useful heat or less as shipped
from the factory.
NOTE: Ultra Low NOx requirements apply only to natural gas
installations.
Install the flue hood as follows:
1. This installation must conform with local building codes and with
NFPA 54/ANSI Z223.1 National Fuel Gas Code (NFGC), (in
Canada, CAN/CGA B149.1, and B149.2) latest revision. Refer to
Provincial and local plumbing or wastewater codes and other
applicable local codes.
2. Remove flue hood from shipping location (inside the return section
of the blower compartment-see Fig. 9). Remove the return duct
cover to locate the flue hood. Place flue hood assembly over flue
panel. Orient screw holes in flue hood with holes in the flue panel.
3. Secure flue hood to flue panel by inserting a single screw on the top
flange and the bottom flange of the hood.
Step 8 – Install Gas Piping
The gas supply pipe enters the unit through the access hole provided.
The gas connection to the unit is made to the 1/2-in. (12.7 mm) FPT gas
inlet on the gas valve.
Install a gas supply line that runs to the heating section. Refer to the
NFGC for gas pipe sizing. Do not use cast-iron pipe. It is recommended
that a black iron pipe is used. Check the local utility for
recommendations concerning existing lines. Size gas supply piping for
0.5 IN. W.C. maximum pressure drop. Never use pipe smaller than the
1/2-in. (12.7 mm) FPT gas inlet on the unit gas valve.
For natural gas applications, the gas pressure at unit gas connection must
not be less than 4.0 IN. W.C. or greater than 13 IN. W.C. while the unit is
operating.
A 1/8-in. (3.2 mm) NPT plugged tapping, accessible for test gauge
connection, must be installed immediately upstream of the gas supply
connection to the gas valve.
When installing the gas supply line, observe local codes pertaining to
gas pipe installations. Refer to the NFPA 54/ANSI Z223.1 latest edition
(in Canada, CAN/CGA B149.1).
NOTE: In the state of Massachusetts:
1. Gas supply connections MUST be performed by a licensed plumber
or gas fitter.
2. When flexible connectors are used, the maximum length shall not
exceed 36 inches (915 mm).
3. When lever handle type manual equipment shutoff valves are used,
they shall be T-handle valves.
4. The use of copper tubing for gas piping is NOT approved by the
state of Massachusetts.
In the absence of local building codes, adhere to the following pertinent
recommendations:
1. Avoid low spots in long runs of pipe. Grade all pipe 1/4 in. (6.35
mm) for every 15 ft (4.6 m) of length to prevent traps. Grade all
horizontal runs downward to risers. Use risers to connect to heating
section and to meter.
2. Protect all segments of piping system against physical and thermal
damage. Support all piping with appropriate straps, hangers, etc.
Use a minimum of one hanger every 6 ft (1.8 m). For pipe sizes
larger than 1/2 in., follow recommendations of national codes.
3. Apply joint compound (pipe dope) sparingly and only to male
threads of joint when making pipe connections. Use only pipe dope
that is resistant to action of liquefied petroleum gases as specified
by local and/or national codes. Never use Teflon tape.
4. Install sediment trap in riser leading to heating section (See Fig. 8).
This drip leg functions as a trap for dirt and condensate.
5. Install an accessible, external, manual main shutoff valve in gas
supply pipe within 6 ft (1.8 m) of heating section.
6. Install ground-joint union close to heating section between unit
manual shutoff and external manual main shut-off valve.
7. Pressure test all gas piping in accordance with local and national
plumbing and gas codes before connecting piping to unit.
WARNING
!
CARBON MONOXIDE POISONING HAZARD
Failure to follow this warning could result in personal injury or death.
The venting system is designed to ensure proper venting. The flue hood
assembly must be installed as indicted in this section of the unit
installation instructions.
TRAP
OUTLET
1-in. (25 mm) min.
2-in. (51 mm) min.

48VGUK: Installation Instructions
Manufacturer reserves the right to change, at any time, specifications and designs without notice and without obligations.
11
C99020
Fig. 8 – Sediment Trap
NOTE: Pressure test the gas supply system after the gas supply piping
is connected to the gas valve. The supply piping must be disconnected
from the gas valve during the testing of the piping systems when test
pressure is in excess of 0.5 psig. Pressure test the gas supply piping
system at pressures equal to or less than 0.5 psig. The unit heating
section must be isolated from the gas piping system by closing the
external main manual shutoff valve and slightly opening the
ground-joint union. 8. Check for gas leaks at the field-installed and factory-installed gas
lines after all piping connections have been completed. Use a
commercially available soap solution (or method specified by local
codes and/or regulations).
Step 9 – Install Duct Connections
The unit has duct flanges on the supply- and return-air openings on the
side and bottom of the unit. For downshot applications, the ductwork
connects to the roof curb (See Fig. 3 and Fig. 4 for connection sizes and
locations).
Configuring Units for Downflow (Vertical) Discharge
1. Open all electrical disconnects before starting any service work.
2. Remove horizontal (metal) duct covers to access vertical
(downflow) discharge duct knockouts in unit basepan. (See Fig. 9.)
Table 2 – Maximum Gas Flow Capacity*
*. Capacity of pipe in cu ft of gas per hr for gas pressure of 0.5 psig or less. Pressure drop of 0.5-IN. W.C. (based on a 0.60 specific gravity gas). Refer to Table 2 and National Fuel
Gas Code NFPA 54/ANSI Z223.1
NOMINAL
IRON PIPE
SIZE (IN.)
INTERNAL
DIAMETER
(IN.)
LENGTH OF PIPE FT (m)†
†. This length includes an ordinary number of fittings.
10
(3)
20
(6)
30
(9)
40
(12)
50
(15)
60
(18)
70
(21)
80
(24)
90
(27)
100
(30)
125
(38)
150
(46)
175
(53)
200
(61)
1/2 .622 175 120 97 82 73 66 61 57 53 50 44 40 — —
3/4 .824 360 250 200 170 151 138 125 118 110 103 93 84 77 72
1 1.049 680 465 375 320 285 260 240 220 205 195 175 160 145 135
1-1/4 1.380 1400 950 770 600 580 530 490 460 430 400 360 325 300 280
1-1/2 1.610 2100 1460 1180 990 900 810 750 690 650 620 550 500 460 430
OUT
TEE
NIPPLE
CAP
IN
ß0,1
WARNING
!
FIRE OR EXPLOSION HAZARD
Failure to follow this warning could result in personal injury, death
and/or property damage.
- Connect gas pipe to unit using a backup wrench to avoid
damaging gas controls.
- Never purge a gas line into a combustion chamber. Never test
for gas leaks with an open flame. Use a commercially available
soap solution made specifically for the detection of leaks to
check all connections. A fire or explosion may result causing
property damage, personal injury or loss of life.
- Use proper length of pipe to avoid stress on gas control
manifold.
- If a flexible connector is required or allowed by authority
having jurisdiction, black iron pipe shall be installed at furnace
gas valve and extend a minimum of 2 in. (51 mm) outside
furnace casing.
- If codes allow a flexible connector, always use a new connector.
Do not use a connector which has previously serviced another
gas appliance.
WARNING
!
ELECTRICAL SHOCK HAZARD
Failure to follow this warning could result in personal injury or death.
Before installing or servicing system, always turn off main power to
system and install lockout tag. There may be more than one disconnect
switch.

48VGUK: Installation Instructions
Manufacturer reserves the right to change, at any time, specifications and designs without notice and without obligations.
12
3. For single-phase models only, on the discharge side only, remove
the insulation covering the downshot (plastic) knockout. Insulation
is held in place with aluminum tape. Please note that large chassis
units have 2 pieces of insulation, and only the piece over the
downshot knockout needs to be removed. Discard insulation.
4. To remove the downshot (plastic) knockouts for both supply and
returns, break front and right side connecting tabs with a
screwdriver and hammer. Push cover down to break rear and left
side tabs. These plastic knockouts are held in place with tabs
similar to an electrical knockout. Discard plastic knockout covers.
5. Set unit on roof curb.
6. Verify that the downshot ducts are aligned with the downshot
knockout areas.
7. Re-install horizontal (metal) covers as needed to seal unit. Ensure
opensings are air and watertight.
NOTE: The design and installation of the duct system must be in
accordance with the standards of the NFPA for installation of
nonresidence-type air conditioning and ventilating systems, NFPA 90A
or residence-type, NFPA 90B; and/or local codes and ordinances.
Adhere to the following criteria when selecting, sizing, and installing the
duct system:
1. Units are shipped for horizontal duct installation (by removing duct
covers).
2. Select and size ductwork, supply-air registers, and return-air grilles
according to American Society of Heating, Refrigeration and Air
Conditioning Engineers (ASHRAE) recommendations.
3. Use flexible transition between rigid ductwork and unit to prevent
transmission of vibration. The transition may be screwed or bolted
to duct flanges. Use suitable gaskets to ensure weather tight and
airtight seal.
4. All units must have field-supplied filters or accessory filter rack
installed in the return-air side of the unit. Recommended sizes for
filters are shown in Table 1.
A09076
A09077
Fig. 9 – Supply and Return Duct Opening
5. Size all ductwork for maximum required airflow (either heating or
cooling) for unit being installed. Avoid abrupt duct size increases or
decreases or performance may be affected.
6. Adequately insulate and weatherproof all ductwork located
outdoors. Insulate ducts passing through unconditioned space, and
use vapor barrier in accordance with latest issue of Sheet Metal and
Air Conditioning Contractors National Association (SMACNA)
and Air Conditioning Contractors of America (ACCA) minimum
installation standards for heating and air conditioning systems.
Secure all ducts to building structure.
7. Flash, weatherproof, and vibration isolate all openings in building
structure in accordance with local codes and good building
practices.
Step 10 – Install Electrical Connections
CAUTION
!
PROPERTY DAMAGE HAZARD
Failure to follow this caution may result in property damage.
Collect ALL screws that were removed. Do not leave screws on rooftop
as permanent damage to the roof may occur.
Horizontal Duct Covers
WARNING
!
ELECTRICAL SHOCK HAZARD
Failure to follow this warning could result in personal injury or death.
The unit cabinet must have an uninterrupted, unbroken electrical
ground. This ground may consist of an electrical wire connected to the
unit ground screw in the control compartment, or conduit approved for
electrical ground when installed in accordance with NFPA 70 (NEC)
(latest edition) (in Canada, Canadian Electrical Code CSA C22.1) and
local electrical codes.
Basepan
Downflow
(Vertical)
Supply
Knockout
Basepan
Downflow
(Vertical)
Return
Knockout

48VGUK: Installation Instructions
Manufacturer reserves the right to change, at any time, specifications and designs without notice and without obligations.
13
High-Voltage Connections
When routing power leads into unit, use only copper wire between
disconnect and unit. The high voltage leads should be in a conduit until
they enter the duct panel; conduit termination at the duct panel must be
watertight.
The unit must have a separate electrical service with a field-supplied,
waterproof disconnect switch mounted at, or within sight from, the unit.
Refer to the unit rating plate, NEC and local codes for maximum
fuse/circuit breaker size and minimum circuit amps (ampacity) for wire
sizing.
The field-supplied disconnect switch box may be mounted on the unit
over the high-voltage inlet hole when the standard power and
low-voltage entry points are used (See Fig. 3 and Fig. 4 for acceptable
location).
NOTE: Field supplied disconnect switch box should be positioned so
that it does not cover up any of the unit gas combustion supply air
louvers.
See unit wiring label (Fig. 15 - Fig. 18) and Fig. 10 for reference when
making high voltage connections. Proceed as follows to complete the
high-voltage connections to the unit.
Single phase units:
1. Run the high-voltage (L1, L2) and ground lead into the control box.
2. Connect ground lead to chassis ground connection.
3. Locate the black and yellow wires connected to the line side of the
contactor (if equipped).
4. Connect field L1 to black wire from connection 11 of the
compressor contactor.
5. Connect field wire L2 to yellow wire from connection 23 of the
compressor contactor.
Three-phase units:
1. Run the high-voltage (L1, L2, L3) and ground lead into the control
box.
2. Connect ground lead to chassis ground connection.
3. Locate the black and yellow wires connected to the line side of the
contactor (if equipped).
4. Connect field L1 to black wire from connection 11 of the
compressor contactor.
5. Connect field wire L3 to yellow wire from connection 13 of the
compressor contactor.
6. Connect field wire L2 to blue wire from compressor.
Special Procedures for 208-v Operation
Control Voltage Connections
Do not use any type of power-stealing thermostat. Unit control problems
may result.
Use no. 18 American Wire Gage (AWG) color-coded, insulated (35°C
minimum) wires to make the control voltage connections between the
thermostat and the unit. If the thermostat is located more than 100 ft
(30.5 m) from the unit (as measured along the control voltage wires), use
no. 16 AWG color-coded, insulated (35°C minimum) wires.
Standard Connection
Run the low-voltage leads from the thermostat, through the inlet hole,
and into unit low-voltage splice box.
Locate eight 18-gage wires leaving control box. These low-voltage
connection leads can be identified by the colors red, green, yellow,
brown, blue, and white (See Fig. 10). Ensure the leads are long enough
to be routed into the low-voltage splice box (located below right side of
control box). Route leads through hole in bottom of control box and
make low-voltage connections (See Fig. 10). Secure all cut wires, so that
they do not interfere with operation of unit.
CAUTION
!
UNIT COMPONENT DAMAGE HAZARD
Failure to follow this caution may result in damage to the unit being
installed.
1. Make all electrical connections in accordance with NFPA 70
(NEC) (latest edition) and local electrical codes governing such
wiring. In Canada, all electrical connections must be in
accordance with CSA standard C22.1 Canadian Electrical Code
Part 1 and applicable local codes. Refer to unit wiring diagram.
2. Use only copper conductor for connections between
field-supplied electrical disconnect switch and unit. DO NOT
USE ALUMINUM WIRE.
3. Be sure that high-voltage power to unit is within operating
voltage range indicated on unit rating plate. On 3-phase units,
ensure phases are balanced within 2 percent. Consult local
power company for correction of improper voltage and/or phase
imbalance.
4. Insulate low-voltage wires for highest voltage contained within
conduit when low-voltage control wires are in same conduit as
high-voltage wires.
5. Do not damage internal components when drilling through any
panel to mount electrical hardware, conduit, etc.
6. Route field power supply(s) away from areas that could be
damaged by lawn and garden equipment or other accidental
damage.
WARNING
!
ELECTRICAL SHOCK HAZARD
Failure to follow this warning could result in personal
injury or death.
Make sure the power supply to the unit is switched OFF and install
lockout tag. before making any wiring changes.With disconnect switch
open, move black wire from transformer (3/16 in. [4.8 mm]) terminal
marked 230 to terminal marked 208. This retaps transformer to primary
voltage of 208 vac.
CAUTION
!
ELECTRICAL SHOCK FIRE/EXPLOSION HAZARD
Failure to follow this warning could result in personal
injury or death and property damage.
Before making any wiring changes, make sure the gas
supply is switched off first. Then switch off the power

48VGUK: Installation Instructions
Manufacturer reserves the right to change, at any time, specifications and designs without notice and without obligations.
14
A13016
Fig. 10 – High- and Control-Voltage Connections
IMPORTANT: Dehumidification control must open control circuit on
humidity rise above set point.
Use of the dehumidification cooling fan speed requires use of either a 24
VAC dehumidistat or a thermostat which includes control of a 24 VAC
dehumidistat connection. In either case, the dehumidification control
must open the control circuit on humidity rise above the
dehumidification set point.
Heat Anticipator Setting (Electro-Mechanical
Thermostats only)
The room thermostat heat anticipator must be properly adjusted to
ensure proper heating performance. Set the heat anticipator, using an
ammeter between the W1 and R terminals to determine the exact
required setting.
NOTE: For thermostat selection purposes, use 0.18 amp for the
approximate required setting. Failure to make a proper heat anticipator
adjustment will result in improper operation, discomfort to the occupants
of the conditioned space, and inefficient energy utilization; however, the
required setting may be changed slightly to provide a greater degree of
comfort for a particular installation.
Transformer Protection
The transformer is of the energy-limiting type, however a direct short
will likely blow a secondary fuse. If an overload or short is present,
correct overload condition and check for blown fuse on Indoor Fan
board or Integrated Gas Controller. Replace fuse as required with correct
size and rating.
Pre-Start-up
Use the Start-Up Checklist supplied at the end of this book and proceed
as follows to inspect and prepare the unit for initial start-up:
1. Remove access panels (see Fig. 22).
2. Read and follow instructions on all DANGER, WARNING,
CAUTION, and INFORMATION labels attached to, or shipped
with unit.
3. Make the following inspections:
a. Inspect for shipping and handling damage, such as broken lines,
loose parts, disconnected wires, etc.
b. Inspect all field- and factory-wiring connections. Be sure that
connections are completed and tight.
c. Ensure wires do not touch refrigerant tubing or sharp sheet metal
edges.
d. Inspect coil fins. If damaged during shipping and handling,
carefully straighten fins with a fin comb.
POWER
SUPPLY
FIELD-SUPPLIED
FUSED DISCONNECT
HIGH VOLTAGE
POWER LEADS
(SEE UNIT WIRING
LABEL)
EQUIP GR
3-PHASE SHOWN
1-PHASE USES
TWO POWER
LEADS
SPLICE BOX
LOW-VOLTAGE
POWER LEADS
(SEE UNIT
WIRING LABEL)
WHT(W1)
W/W1
YEL (Y)
Y1/Y
G
GRN(G)
RED(R)
BRN(C)
BLU(DH)
R
C
DH
Y2
W2
PINK(Y2)
BLK(W2)
CONTROL BOX
(W2 ON 208/230 VAC
MODELS ONLY)
THERMOSTAT
(TYPICAL)
(DH ON 208/230 VAC
MODELS ONLY)
WARNING
!
ENVIRONMENTAL, FIRE, EXPLOSION, ELECTRICAL
SHOCK HAZARD
Failure to follow this warning could result in personal injury or death.
1. Follow recognized safety practices and wear protective goggles
when checking or servicing refrigerant system.
2. Do not operate compressor or provide any electric power to unit
unless compressor plug is in place and secured.
3. Do not remove compressor plug until all electrical sources are
disconnected and tagged.
4. Relieve and recover all refrigerant from system before touching
or disturbing compressor plug if refrigerant leak is suspected
around compressor terminals.
5. Never attempt to repair soldered connection while refrigerant
system is under pressure.
6. Do not use torch to remove any component. System contains oil
and refrigerant under pressure.
To remove a component, wear protective goggles and proceed
as follows:
a.Shut off electrical power to unit and install lockout tag.
b.Relieve and reclaim all refrigerant from system using both
high- and low-pressure ports.
c.Cut component connecting tubing with tubing cutter and
remove component from unit.
d.Carefully unsweat remaining tubing stubs when necessary. Oil
can ignite when exposed to torch flame.
WARNING
!
FIRE, EXPLOSION HAZARD
Failure to follow this warning could result in personal injury, death or
property damage.
Do not purge gas supply into the combustion chamber. Do not use a
match or other open flame to check for gas leaks.
Use a commercially available soap solution made specifically for the
detection of leaks to check all connections. A fire or explosion may
result causing property damage, personal injury or loss of life.

48VGUK: Installation Instructions
Manufacturer reserves the right to change, at any time, specifications and designs without notice and without obligations.
15
4. Verify the following conditions:
a. Make sure gas line is free of air. Before lighting the unit for the
first time, perform the following with the gas valve in the OFF
position:
NOTE: If the gas supply pipe was not purged before connecting the
unit, it will be full of air. It is recommended that the ground joint union
be loosened, and the supply line be allowed to purge until the odor of gas
is detected. Never purge gas lines into a combustion chamber.
Immediately upon detection of gas odor, retighten the union. Allow 5
minutes to elapse, then light unit.
b. Make sure that outdoor-fan blade is correctly positioned in the
fan orifice.
c. Make sure that air filter(s) is in place.
d. Make sure that condensate drain trap is filled with water to
ensure proper drainage.
e. Make sure that all tools and miscellaneous loose parts have been
removed.
Start-up
Step 1 – Check for Refrigerant Leaks
Proceed as follows to locate and repair a refrigerant leak and to charge
the unit:
1. Locate leak and make sure that refrigerant system pressure has been
relieved and reclaimed from both high- and low-pressure ports.
2. Repair leak following accepted practices.
NOTE: Install a filter drier whenever the system has been opened for
repair.
3. Add a small charge of Puron (R-410A) refrigerant vapor to system
and leak-test unit.
4. Recover refrigerant from refrigerant system and evacuate to 500
microns if no additional leaks are found.
5. Charge unit with Puron (R-410A) refrigerant, using an accurate
scale. Refer to unit rating plate for required charge.
Step 2 – Start-up Heating and Make Adjustments
Complete the required procedures given in the Pre-Start-Up section
before starting the unit. Do not jumper any safety devices when
operating the unit. Make sure that burner orifices are properly aligned.
Unstable operation my occur when the burner orifices in the manifold
are misaligned.
Follow the lighting instructions on the heating section operation label
(located on the inside of the control access panel) to start the heating
section.
NOTE: Make sure that gas supply has been purged, and that all gas
piping has been checked for leaks.
A180078
Fig. 11 – Burner Assembly
A200293
Fig. 12 – Monoport Burner
Check Heating Control
Start and check the unit for proper heating control operation as follows
(see furnace lighting instructions located on the inside of the control
access panel):
For 208/230 VAC Models:
Start and check the unit for proper heating control operation as follows
(see furnace lighting instructions located on the inside of the control
access panel):
1. Place room thermostat SYSTEM switch in the HEAT position and
the fan switch is placed in AUTO position.
2. Set the heating temperature control of the thermostat above room
temperature.
3. On a call for heating, the inducer motor will start up for a 30 second
pre-purge.
4. The control will then check to see the pressure switch closed. Then
the main burner should light within 5 sec. of the spark being
energized. If the burners do not light, there is a 22-sec. delay before
another 5-sec. try. If the burners still do not light, this sequence is
repeated. If the burners do not light on the 4th ignition attempt,
there is a lockout. To reset the control, break the 24-v power to W.
NOTE: The ULN system will sound different from a traditional furnace
that utilizes inshot burners. For the ULN system, the access door is part
of the system and must be installed on the unit for any sound
evaluations.
WARNING
!
FIRE, INJURY, OR DEATH HAZARD
Failure to follow this warning could result in property damage, personal
injury, or death.
Do not bypass any of the safety controls in the unit, including but not
limited to the main limit switch, rollout or burner rollout switch, and
pressure switch/pressure transducer.
WARNING
!
EXPLOSION HAZARD
Failure to follow this warning could result in
death, serious personal injury, and/or property
damage.
Never use air or gases containing oxygen for leak
testing or operating refrigerant compressors.
Pressurized mixtures of air or gases containing
oxygen can lead to an explosion.

48VGUK: Installation Instructions
Manufacturer reserves the right to change, at any time, specifications and designs without notice and without obligations.
16
5. The evaporator fan will turn on 30 sec. after the flame has been
established. The evaporator fan will turn off 90 sec. after the
thermostat has been satisfied. Please note that the integrated gas
unit controller (IGC) has the capability to automatically reduce the
evaporator “ON” delay and increase the evaporator “OFF” delay in
the event of high duct static and/or partially-clogged filter.
Check Gas Input
Check gas input and manifold pressure after unit start-up (See Table 5).
If adjustment is required proceed as follows:
• The rated gas inputs shown in Table 5 are for altitudes from sea level
to 2000 ft (610 m) above sea level. These inputs are based on natural
gas with a heating value of 1025 Btu/ft3 at 0.60 specific gravity.
When the gas supply being used has a different heating value or specific
gravity, refer to national and local codes, or contact your distributor to
determine the required orifice size.
Adjust Gas Input
The gas input to the unit is determined by measuring the gas flow at the
meter or by measuring the manifold pressure. Measuring the gas flow at
the meter is recommended for natural gas units.
Measure Gas Flow (Natural Gas Units)
Minor adjustment to the gas flow can be made by changing the manifold
pressure. The manifold pressure must be maintained between 3.2 and 3.8
IN. W.C.
A07551
Fig. 13 – Single-Stage Gas Valve (208/230 VAC Models)
A170118
Fig. 14 – Single-Stage Gas Valve with Tower Pressure Ports
If larger adjustments are required, change main burner orifices following
the recommendations of national and local codes.
NOTE: All other appliances that use the same meter must be turned off
when gas flow is measured at the meter.
Proceed as follows:
1. Turn off gas supply to unit.
2. Manifold pressure connections
a. For standard gas valves, remove manifold pressure tap cover
using an allen wrench. (See Fig. 13). Install barbed pressure tap
and hose to connect to manometer. Turn on gas supply to unit.
b. For gas valve with tower pressure ports, loosen set screw on
manifold tower pressure tap no more than one full turn with a
3/32-in. hex wrench. (See Fig. 14.) Connect manometer by
sliding 5/16” connecting hose over the manifold tower pressure
port. Turn on gas supply to unit.
3. Record number of seconds for gas meter test dial to make one
revolution.
4. Divide number of seconds in Step 3 into 3600 (number of seconds
in one hr).
5. Multiply result of Step 4 by the number of cubic feet (cu ft) shown
for one revolution of test dial to obtain cubic feet (cu ft) of gas flow
per hour.
6. Multiply result of Step 5 by Btu heating value of gas to obtain total
measured input in Btuh. Compare this value with heating input
shown in Table 5 (Consult the local gas supplier if the heating value
of gas is not known).
EXAMPLE: Assume that the size of test dial is 1 cu ft, one revolution
takes 32 sec, and the heating value of the gas is 1050 Btu/ft3. Proceed as
follows:
1. 41 sec. to complete one revolution
2. 3600 / 41 = 87.8
3. 87.8 x 1 = 87.8 ft3 of gas flow/hr
4. 87.8 x 1050 = 92,190 Btuh input
If the desired gas input is 89,000 Btuh, only a minor change in the
manifold pressure is required.
Observe manifold pressure and proceed as follows to adjust gas input:
1. Remove regulator cover screw over plastic adjustment screw on gas
valve (See Fig. 13 and Fig. 14).
2. Turn plastic adjustment screw clockwise to increase gas input, or
turn plastic adjustment screw counterclockwise to decrease input
(See Fig. 13 and Fig. 14). Manifold pressure must be between 3.2
and 3.8 IN. WC.
NOTE: Manifold pressure must be checked with the access door on.
Table 3 – Altitude Derate Multiplier for U.S.A.
Altitude ft (m) Percent of Derate Derate Multiplier
Factor*
*. Derate multiplier factors are based on midpoint altitude for altitude range.
0-2000
(0-610) 0 1.00
CAUTION
!
UNIT DAMAGE HAZARD
Failure to follow this caution may result in reduced unit and/or
component life.
Do Not redrill an orifice. Improper drilling (burrs, out-of-round holes,
etc.) can cause excessive burner noise and misdirection of burner flame.
If orifice hole appears damaged or it is suspected to have been redrilled,
check orifice hole with a numbered drill bit of correct size.
REGULATOR
COVER SCREW
ADJUSTMENT
SCREW
REGULATOR SPRING
(PROPANE - WHITE)
NATURAL - SILVER)
GAS PRESSURE
REGULATOR
ADJUSTMENT
MANIFOLD
PRESSURE TAP
INLET
PRESSURE TAP
ON/OFF SWITCH
PLASTIC
(

48VGUK: Installation Instructions
Manufacturer reserves the right to change, at any time, specifications and designs without notice and without obligations.
17
3. Replace regulator cover screw on gas valve (See Fig. 13 and
Fig. 14).
4. Turn off gas supply to unit.
5. Removing manometer from pressure tab.
a. For standard gas valve, remove manometer hose and barbed
pressure tap. Replace pressure tap cover using an allen wrench.
(See Fig. 13.)
b. For gas valve with tower pressure port, remove connecting hose.
Tighten set screw on manifold pressure port using a 3/32” hex
wrench. (See Fig. 14.)
6. Turn on gas to unit and check for leaks.
Table 4 – High Altitude Compensation, Natural Gas - Single and Three Phase Models
Nameplate Input (Btu/hr)
Rated Heating Input (Btu/hr), Natural Gas at Installation Altitude Above Sea
Level, U.S.A.
0 to 2000 ft* (0-610 m)
*. Altitude of 2001 ft. and above is not allowed.
45,000 45,000
60,000 60,000
89,000 89,000
Table 5 – Heating Inputs
Heating Input
(BTUH) Number of Orifices
Gas Supply Pressure (IN. W.C.) Manifold Pressure (IN. W.C.)
Natural*
*. Based on altitudes from sea level to 2000 ft (610 m) above sea level.
N/A = Not applicable (Units are not convertible to propane)
Propane
Min Max Min Max Natural*Propane
45,000 1 5 13.0 N/A N/A 3.2~3.8 N/A
60,000 1 4.5 13.0 N/A N/A 3.2~3.8 N/A
89,000 1 5 13.0 N/A N/A 3.2~3.8 N/A
WARNING
!
FIRE AND UNIT DAMAGE HAZARD
Failure to follow this warning could result in personal injury or death
and/or property damage.
Unsafe operation of the unit may result if manifold pressure is outside
this range.
Table 6 – Natural Gas Orifice Sizes and Manifold Pressure
Single and Three Phase Models
Nameplate
Input (Btu/hr)
Altitude of Installation (FT.
Above Sea Level) U.S.A.*
*. In the U.S.A., the input rating for altitudes above 2000 ft (610m) must be
reduced by 4% for each 1000 ft (305 m) above sea level.
In Canada, the input rating for altitudes from 2001 to 4500 ft (611 to 1372 m)
above sea level must be derated by 10% by an authorized gas conversion
station or dealer.
For Canadian Installations from 2000 to 4500 ft (610-1372 m), use U.S.A.
column 2001 to 3000 ft (611 to 914 m).
0 to 2000
(0-610 m)
45,000 Orifice No. (Qty) 0.125-in.
Manifold Press. (in. W.C.) 3.2~3.8
60,000 Orifice No. (Qty) 28 (1)
Manifold Press. (in. W.C.) 3.2~3.8
89,000 Orifice No. (Qty) 18 (1)
Manifold Press. (in. W.C.) 3.2~3.8

48VGUK: Installation Instructions
Manufacturer reserves the right to change, at any time, specifications and designs without notice and without obligations.
18
A230036
Fig. 15 – 208/230-1-60 Connection Wiring Diagram

48VGUK: Installation Instructions
Manufacturer reserves the right to change, at any time, specifications and designs without notice and without obligations.
19
A230037
Fig. 16 – 208/230-1-60 Ladder Wiring Diagram

48VGUK: Installation Instructions
Manufacturer reserves the right to change, at any time, specifications and designs without notice and without obligations.
20
A230038
Fig. 17 – 208/230-3-60 Connection Wiring Diagram Gas Inputs 40, 60, 90 KBtu/hr