These installation instructions cover the outdoor installation of
single package gas-electric heating and cooling units. See the
product catalog applicable to your model for information
regarding specifications applicable to your model and accesso
ries.
Receiving Inspection
McQuay products are carefully inspected prior to shipment
and the carrier has assumed responsibility for loss or damage
upon acceptance of the shipment.
Upon receiving your shipment, check all items carefully
against the Bill of Lading. Inspect the unit and/or accessories
for shipping damage as soon as they are received. Immedi
ately file claims for loss or damage, either shipping or concealed, with the shipping company.
Check the unit nameplate to verify the model number and electrical characteristics are correct. In the event an incorrect unit
is shipped, it must be returned to the supplier and must NOT
be installed. The manufacturer disclaims all responsibility for
the installation of incorrectly shipped units.
Codes and Regulations
This product is designed and manufactured to permit installation in accordance with National Codes. System design
should, where applicable, follow information presented in
accepted industry guides such as the ASHRAE Handbooks. It
is the installer' s responsibility to install the product in accor
dance with National Codes and/or prevailing local codes and
regulations. The manufacturer disclaims all responsibility for
equipment installed in violation of any code or regulations.
Important Message to the Installer
This equipment is to be installed by an experienced installation
company and fully trained personnel. Carefully read all
instructions and take into account any special considerations
prior to installing the unit. Give this manual to the owner and
explain its provisions.
-
-
-
Important Message to the Owner
Read these instructions carefully and keep them near the product for future reference. Although these instructions are
addressed primarily to the installer, useful maintenance infor
mation is included. Have the installer acquaint you with the
operation of the product and periodic maintenance require
ments.
Recognize Safety Symbols, Words, and Labels
The following symbols and labels are used throughout this
manual to indicate immediate or potential hazards. It is the
owner's and installer's responsibility to read and comply with
all safety information and instructions accompanying these
symbols. Failure to heed safety information increases the risk
of property damage and/or product damage, serious personal
injury or death. Improper installation, operation and mainte
nance can void the warranty.
DANGER
Immediate hazards which WILL result in property
damage, product damage, severe personal injury and/
or death.
WARNING
Hazards or unsafe practice CAN result in property
damage, product damage, sever personal injury and/or
death.
CAUTION
Hazards or unsafe practices which CAN result in
property damage, product damage, and/or personal
injury.
Replacement Parts
Replacement parts can be obtained by contacting McQuay at
1-800-
37-PARTS. When contacting McQuay for service or
replacement parts, refer to the model number and serial num
ber of the unit as stamped on the nameplate attached to the
unit.
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Page 4 IM-806
Page 5
GENERAL WARNINGS
DANGER
CARBON MONOXIDE (CO) POISONING HAZARD
CO can cause brain damage and death. It is odorless
and colorless. Do not install this unit in any enclosure
or location where fumes many enter an enclosure.
DANGER
To avoid property damage, personal injury or death, do
not store or use gasoline or other flammable vapors or
liquids in the vicinity of this unit or in any area sharing
ventilation.
WARNING
IF YOU SMELL GAS
• Immediatly evacuate the area.
• Do not try to light any appliances.
• Do not touch any electrical switches.
• Do not use any phones in your building.
• Immediately call your gas supplier from a phone
located in a neighboring building.
• Follow the gas supplier's instructions.
• If you cannot reach your gas supplier, call the fire
department.
Failure to follow these instructions can result in fire,
explosion, severe personal injury or death.
WARNING
If overheating occurs or the gas supply fails to shut off,
turn off the manual gas shutoff valve outside the
furnace before turning off the electricity supply to avoid
property damage, severe personal injury or death.
WARNING
To avoid property damage, personal injury or death, do
not use this unit if any part has been under water.
Immediately call a qualified service technician to
inspect the furnace and replace any affected part.
WARNING
This product contains or produces substances which
may cause serious illness or death, and which are
known to the State of California to cause cancer, birth
defects or other reproductive harm.
WARNING
To avoid property damage, personal injury or death,
follow the planned maintenance instructions provided in
the "Maintenance" section of this document.
CAUTION
Freezing can burst pipes. Routinely inspect and
monitor unit and premise. If vacant, drain all water
pipes and close water source. Drain hydronic coils and
use alternative heat source.
CAUTION
Do not use this unit as a "construction heater" during
finishing phases of construction on a new structure.
Extremely low return air temperatures and corrosive or
dirty atmosphere can damage unit.
CAUTION
Sheet metal parts, screws, clips and similar items have
sharp edges. Use caution and wear protective clothing
when installing or servicing this equipment.
CAUTION
Keep these instructions in a safe and accessible space
for future reference or in case of an emergency.
IM-806 Page 5
Page 6
DIMENSIONAL DATA
Figure 1. Vertical and Horizontal Discharge
All dimensions in inches; no scale
Vertical Discharge
(Factory Configuration)
40
17 9/32
74 9/16
A
74 9/16
17 9/32
5 7/8
18
4
18
28 11/16
Horizontal Discharge
(With Field Installed
Accessory)
17 9/32
MODELA
HEIGHT
Table 2: Horizontal discharge (with field
installed accessory)
Model
090 102
Height
120, 150
0903612 1/217 9/16
180
*Field Installed Accessory.
1205220 1/425 13/16
36 12 1/217 9/16
A
Supply Air
52 20 1/425 13/16
SUPPLY
B
B
AIR
C
Return Air
*
RETURN
AIR
C
40
3/4
*
17 9/32
7/8
C
1 9/32
B
3 25/32
Page 6 IM-806
Page 7
COMPONENT LOCATION
Figure 2. Typical Component Location
CLEARANCES
Keep adequate clearance around the unit for service, maintenance and proper unit operation. Keep a total clearance of 75"
on the main control panel side of the unit to facilitate possible
fan shaft, coil, electric heat and gas furnace removal (Figure
3). Keep a clearance of 48"on all other sides of the unit to
facilitate possible compressor removal, to allow service access
and to provide proper ventilation and condenser airflow. The
unit must not be installed beneath any obstruction. The unit
must be installed away from all building exhausts, windows,
vents and other entrances to any enclosure. Exhaust air must
not enter an enclosure or any unit fresh air intake
DANGER
CARBON MONOXIDE (CO) POISONING HAZARD
CO can cause brain damage and death. It is odorless
and colorless. Do not install this unit in any enclosure
or location where fumes many enter an enclosure.
Figure 3. Minimum Clearance — Gas Heat Units
.
GAS HEAT UNITS
1. As indicated in Figure 3 and on the unit's nameplate, a minimum clearance of 36" to any combustible material is
required on the furnance access side of the unit. All com
-
bustible materials must be kept out of this area.
2. This 36" clearance must also be maintained to provide
proper combustion air and flue gas flow. The combustion
air intake and furance flue discharge must not be blocked
for any reason, including blockage by snow.
3. Adequate clearances from the furnace flue discharge to any
adjacent public walkways, adjacent buildings, building
openings or openable windows must be maintained in
accordance with the latest edition of the National Fuel Gas
Code (ANSI Z223.1)
4. A minimum horizontal clearance of 48" from the furnace
flue discharge to any electric meters, gas meters, regulators
and relief equipment is required.
Note: Model RG090 through 120 rooftop units are
designed for outdoor installation only. They may be
installed over wood flooring or over Class A, B or C
roof covering materials.
48"
36"
Min.
75"
IM-806 Page 7
48"
48"
Page 8
ROOF CURB ASSEMBLY
& INSTALLATION
GENERAL
1. Roof curbs are shipped unassembled. Field assembly,
squaring, leveling and mounting on the roof structure are the
responsibility of the installing contractor. All curb installatons
must comply with local codes and should be done in accor
dance with the established guidelines of the National Roofing
Contractors Association.
2. All required hardware necessary for the assembly of the
sheet metal curb is included in the curb accessory.
3. Full perimeter type curb accessories are available. Cantile-
ver type curbs are not available from the factory. Dimensions shown can be used for fabrication in the field. The
full perimeter curb (PGC-5) includes a duct connection
frame to be assembled with the curb. A separate duct con
nection frame can be constructed for use with the cantilever
curb. The unit can be set on the cantilever curb so that
either the condenser end or the two sides overhang the
curb.
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-
4. Assemble the duct connection frame accessory as shown in
Figure 6. Fasten the pieces together using the sheet metal
screws provided (3/8" hex head).
Note: The duct connection frame can be oriented two ways
when set into the curb. The frame position must cor
respond to the intended unit orientation on the curb.
The gasket provided with the duct connection acces
sory should be applied after duct installation. Refer
to the "Vertical Discharge Duct Connections" sec
tion of these instructions.
Figure 4. Cantilever Curb Joint
-
-
-
4. Curbs must be supported on at least two parallel sides by
roof members. Roof members must not penetrate supply
and return duct opening areas.
5. Curb insulation, cant strip, flashings and general roofing
materials are to be furnished by the contractor. Wood nail
ing strip and curb gasketing are furnished with the curb
accessory.
6. The unit and curb accessories are designed to allow vertical
duct installation before unit placement. Do not install duct
after unit placement.
ASSEMBLY
CAUTION
All curbs look similar. To avoid incorrect curb
positioning, check job plans carefully and verify
markings on the curb assembly. Instructions may vary
with curb styles and supersede the information shown.
Cantilever Curb:
1. Position the perimeter pieces, items 1 and 2, as shown in
Figure 4. Check the lengths of all pieces against the bill of
material to verify proper placement and assembly.
2. Assemble side channels, item 1, to the front and back channels, item 2, using bolts, washers, lock washers, and nuts
(items 3, 4, 5 and 6). Hand tighten ONLY at this time.
Note: Flanges on item 1 must go outside of item 2 and
under the wood nailer strip. Curb styles may vary, so
check the curb instructions.
3. Referring to Table 3 and Figure 5, the assembled roof
mounting curb should now be checked for squareness. The
curb assembly must be adjusted until both diagonal mea
surements, dimension "C", are equal within a tolerance of
1/8". All hand tightened fasteners should now be fully
secured.
Page 8 IM-806
Page 9
Full Perimeter Curb:
R
1. Position perimeter pieces, item A, as shown in Figures 7
and 8. All perimeter pieces are identical.
2. The duct connection frame, items B and C, should be
assembled with the curb as shown in Figures 7 and 8.
Note: The top of the duct connection frame must be flush
with the top of the curb as shown in Figure 7.
3. Fasten the pieces together using the sheet metal screws
provided (item D). Use three screws at each corner of the
curb frame (item A), when positioned, and two screws at
each joint of the duct connection members (items B and C).
4. The assembled roof mounting curb should now be checked
for squareness. Referring to Table 3 and Figure 5, the curb
assembly must be adjusted until both diagonal measure
ments (dimension "C") are equal within a tolerance of 1/8".
5. Gasket material sufficient to seal the curb perimeter and the
duct connection frame is included and attached to a duct
connection member
.
Figure 8. Full Perimeter Curb Detail
18-23/32
3-9/32
18-23/32
Note: Do not apply gasket material to the curb perimeter
and the duct connection frame until the ducts are
placed in the frame. Refer to the "Vertical Discharge
Duct Connections" section of these instructions.
Figure 7. Full Perimeter Curb
-
40-23/32
63-9/16
68-1/16
4
1
2
68-1/16
63-9/16
2-1/4
3-1/4
1-1/2
5-1/2
3-1/4
UNIT BOTTOM
2-1/4
14
4
1
3-1/2
2
26-5/32
3
9-5/8
WOOD NAILER
SUPPLIED
WITH CURB
3
4
DUCT
SUPPORT
(B)
1-1/2
CURB
PERIMETER
(A)
GASKETING BETWEEN
SUPPLY AIR
3-9/32
NOT SHOWN: INSULATION, CANT STRIP,
FLASHING AND ROOFING MATERIALS
BY OTHERS
UNIT & CURB
DUCT
SUPPORT
(C)
RETURN AI
FIELD SUPPLIED
DUCT
IM-806 Page 9
Page 10
INSTALLATION
6
1. Place the assembled curb in the proper location over the
roof opening. Check for squareness and adjust if required.
2. Curb installation must be level. One method to achieve a
level installation is to stretch two diagonal lines equipped
with line levels across the curb. There must not be more
than 1/8" spacing between the two lines at the point of
intersection. If the lines touch at the intersection, recheck
by placing the bottom line on top. Shim curb as required to
bring it to within the specified tolerance.
3. Attach the squared and leveled curb to the roof structure
following industry accepted practice.
4. Install insulation, cant strip, roofing materials, flashing, and
counterflashing in accordance with the established guide
lines of the National Roofing Contractors Association. The
finished roof, including counterfiashing around the curb,
must be installed prior to setting the unit on the curb.
placement is possible, but not recommended. Ducts must never
be fastened to the bottom of the unit, as the base pan may be
penetrated. Use flexible duct connectors in the ducts near the
unit. Support all ducts by securing them to the building struc
ture. Weatherproof all external ductwork, joints and roof openings with flashing and mastic in accordance with applicable
codes. Ducts in an unconditioned space must be insulated and
covered with a vapor barrier.
DUCT INSTALLATION BEFORE UNIT PLACEMENT
Ductwork may be installed prior to unit placement by using a
duct connection frame. Two duct connection frame systems fit
into the three possible curb configurations as shown in Figures
8, 9 and 10. The frame to be used with full perimeter curbs is
included with the curbs. It must be assembled and attached to
the curb as shown in Figures 7 and 8. The frame to be used
with either configuration of the cantilever curb should be fabri
cated by installing contractor. It must be assembled as shown
in Figure 6 and then set into the curb as shown in Figures 9 and
10. Fastening the frame to the curb is not necessary.
VERTICAL DISCHARGE DUCT CONNECTIONS
The unit curb accessories have been designed to allow duct
installation before unit placement. Duct installation after unit
After the duct connection system has been assembled and
installed, the ductwork may be set in place. To make the con
nection, prepare the duct with a 1-1/2" flange as shown in Figures 11 and 12. Then, place the section into position on the
connection frame. Riveting or bolting is not necessary and is
not recommended. Both duct connection systems include gas
keting, which must be applied to the connection frame and
duct flanges after duct installation. Gasket must be installed
over the duct flanges so that an airtight seal is made between
the unit and the ductwork after the unit is placed on the curb.
Figure 11. Duct Placement (Full Perimeter Curb)
45
2 29/32
6 3/8
2 3/8
49 3/4
12 13/32
Figure 12. Duct Placement (Cantilever Curb)
-
-
Full Perimeter Curb
All gasketing must be field installed on the full perimeter curbs
as shown in Figure 8. After duct sections have been installed,
apply gasketing supplied with the curb accessory over the duct
flanges, exposed connection frame and curb penmeter.
Cantilever Curb
All gasketing must be field installed on the perimeter of the
curb. After the duct connection frame and duct sections have
been set on the curb, field-supplied gasketing should be
applied over the duct flanges and exposed frame as shown in
Figures 9 and 10.
IM-806 Page 11
Page 12
DUCT INSTALLATION AFTER UNIT PLACEMENT
Duct installation after the unit has been placed is not recommended. If ductwork must be installed after the unit is placed
on the curb, one of the duct connection frame systems should
still be used. Apply gasketing to the curb and duct connection
frames before unit placement as shown in Figures 8, 9, and 10.
The duct sections should be fastened to the vertical flanges of
the connection frame and curb and sealed as required. Ducts
must never be fastened to the bottom of the unit, as they may
cause the base pan to be penetrated.
HANDLING AND RIGGING
GENERAL
To assist in determining rigging requirements, unit weights are
shown as follows:
Figure 13. Corner and Center of Gravity Locations
NOTES:
1. Weights are for basic cooling only unit; no options.
2. Add 50% of weight listed to corners A and D.
3. Add 50% of weight listed to corners B and C.
4. Add 25% of weight listed to each corner.
5. Center of gravity weights are for cooling only units with no
options
Provisions for forks have been included in the unit base frame
on three sides. If unit is moved by forklift, no other fork loca
tions are approved.
Do not stand or walk on the unit. Do not drill holes anywhere
in the panels or in the base frame of the unit. Unit access pan
els provide structural support. Do not remove any access panels until unit has been installed on roof curb or field supplied
structure. Do not roll unit across finished roof without prior
approval of owner or achitect. Do not skid or slide on any sur
face as this may damage unit base. The unit must be stored on
a flat, level surface. Provisions must be made to protect the
condenser coil from damage.
CAUTION
If units are to be lifted two at a time, the fork holes on
the condenser end of the unit must not be used.
Minimum fork length is 42" to prevent damage to the
unit. However, 48" is recommended.
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-
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Table 4: Unit and Component Weights (lbs.) and Center of
Gravity (inches)
Data
Corner Weight - A
Corner Weight - B
Corner Weight - C
Corner Weight - D
Center of Gravity - X (in.)
Center of Gravity - Y (in.)
Unit Shipping Weight
Unit Operating Weight
Coil Guards
Motorized O.A. Actuator
Economizer
Gas Heat - Model 195
Gas Heat - Model 222
Electric Heater
Full Perimeter Curb
Cantilever Curb11211 2
Cantilever Curb Duct Support2727
1
1
1
1
5
5
1
1
2
3
3
4
4
4
4
RG/RE
090120
304367
245318
196267
235318
33.534.2
34.534.5
10001290
9801270
3040
55
2839
110120
120130
85100
120120
RIGGING DETAILS
1. Unit must be lifted by the four lifting holes located at the
base frame corners.
2. Attach lifting cables to the unit with shackles as shown in
Figure 14.
3. The distance between the crane hook and the top of the unit
must not be less than 60".
4. Two spreader bars must span over the unit to prevent dam-
age to the cabinet by the lift cables. Spreader bars must be
of sufficient length so that cables do not come into contact
with the unit during transport. Remove wood struts
mounted beneath unit base frame before setting the unit on
roof curb. These struts are intended to protect the unit base
frame from forklift damage. Remove struts by extracting
the sheet metal retainers and pulling the struts through the
base of the unit. Refer to the rigging label on the unit.
CAUTION
Do not fork lift unit after wood struts have been
removed; severe damage will occur to the bottom of the
unit.
Page 12 IM-806
Page 13
RIGGING REMOVAL
Remove spreader bars, lifting cables and other rigging equipment.
Figure 14. Rigging
UNIT INSTALLATION ON ROOF
CURB
LOCATION
Units may look identical, but they can have significant internal
differences. Check the specific unit location carefully, referring
to plans if necessary, prior to setting the unit.
CURB INSTALLATION
The roof curb must be firmly and permanently attached to the
roof structure. Check for adequate fastening method prior to
setting the unit on the curb. Verify that the top of the duct con
nection frame is flush with the top of the roof curb. Refer to
the "Roof Curb Assembly & Installation" section of this man
ual. Check the top of the curb, duct connection frame and duct
flanges to verify that the gasket has been applied properly.
Apply gasket firmly to the top of the curb perimeter, duct
flanges and any exposed duct connection frame. If the gasket
is loose, re-apply using strong weather-resistant adhesive.
PROTRUSION
Inspect the curb to verify that none of the utility services (electric) routed through the curb protrude above the curb.
WARNING
To avoid damage or electrical shock, do not attempt to
set unit on the curb if protrusions exist.
UNIT INSTALLATION
Carefully lower the unit onto the roof curb. While rigging the
unit, the center of gravity may cause condenser end to be
slightly lower than supply/return air end. Bring the condenser
end of unit into alignment with the curb. With condenser end
of the unit resting on the curb member and using the curb as a
fulcrum, lower the opposite end of the unit until the entire unit
is seated on the curb. When a rectangular cantilever curb is
used, take care to center the unit. Check for proper alignment
and orientation of the supply and return openings with the
duct. Refer to the "Roof Curb Assembly & Installation" sec
tion of this manual.
CAUTION
To avoid equipment damage, do not allow crane hooks
or spreader bars to rest on on the roof of the unit.
HORIZONTAL DISCHARGE DUCT
CONNECTIONS
A 3/4" flange is provded for making duct connections on units
with the optional field installed horizontal discharge kit. Refer
to Figure 15. Units not equipped with an economizer may be
converted from vertical to horizontal discharge in the field by
using accessory number PGHDK0905A (RE090 and RG090)
or PGHDK1205 (RE120 and RG120). The kits include parts
for conversion to horizontal duct installation. The kit provides
3/4" duct flanges with the dimensions shown in Figure 15 and
Table 5.
Use flexible duct connectors between the unit and ducts. Insulate and weatherproof all external ductwork and joints as
required and in accordance with local codes.
If fresh air is required for the installation, three alternatives are
available.
Manual Fresh Air Damper-A manual fresh air damper
(PGMD-5) is available for 0% to 25% outside air. Two may be
used in the locations shown in Figure 2 for a maximum
of 50% outside fresh air.
Motorized Fresh Air Damper- A motorized fresh air damper
(PGMDM-5) is available and is mounted in the same locations
shown in Figure 2.
Economizer- (PGED090-5A & PGED120-5A) A full
modulation enthalpy controlled economizer is available for
field installation. It is mounted between fresh air damper
blockoff locations. See accessory instructions for
installation.
7/8
C
B
C
Return Air
-
19/32
IM-806 Page 13
Page 14
ELECTRICAL INSTALLATION
WARNING
Do not tamper with factory wiring. The internal power
and control wiring of these units is factory installed and
each unit is thoroughly tested prior to shipment. Contact
the factory or your local representative if assistance is
required.
INSTRUCTIONS
1. The main power supply wiring to the unit and low voltage
wiring to accessory controls must be done in accordance
with these instructions, the latest edition of the National
Electncal Code (ANSI/NFPA 70), and all local codes and
ordinances. All field wiring shall conform with the temper
ature limitations for Type T wire (63°F/35°C rise).
2. Main power and low voltage wiring may enter the unit
through the side or, with some models and curb configura
tions, through the roof curb and base frame. Refer to Figures 16 and 17 for external electrical entrance locations.
Refer to Table 6 and Figures 8, 9, 10 and 18 for the
through-the-curb electrical entrance locations. Install con
duit connectors at the desired entrance locations. External
connectors must be weatherproof. All holes in the unit base
must be sealed, including around conduit nuts, to prevent
water leakage into building. All required conduit and fit
tings must be supplied by others.
3. Bring an independant 115V power source to the vicinity of
the rooftop unit for portable lights and tools used by service
personnel.
Figure 18. Through The Curb Electrical Enterance Locations
-
-
1
7
8
6
5
3
2
4
16 27/32
6 1/4
MAIN
POWER
LOW VOLTAGE
12
6 21/32
Table 6: Through The Curb Electrical Enterance Locations
Curb Configuration
Model Type
Cooling Only438721
Gas Heat438721
Electric Heat635, 67N/A1
Full Perimeter
Power
Low
Vol tag e
Condenser
Overhang
Power
Low
Vol tag e
Side Overhang
Power
Vol tag e
Low
Page 14 IM-806
Page 15
ELECTRICAL ENTRANCE LOCATIONS
1. Protect wiring from sharp edges. Follow National Electrical
Code and all local codes and ordinances. Do not route
wires through removable access panels.
2. Locations 7 and 8 require wiring to exit unit through the
base rail and then re-enter the unit at the external electrical
entrance locations shown in Figures 9, 16, and 17.
3. Locations 1 and 2 require wiring to be routed through the
back of the main control box. Refer to Figure 9.
4. Some disconnect switches are not fused. The power leads
must be protected at the point of distribution in accordance
with the unit nameplate.
5. The unit must be electrically grounded in accordance with
local codes or, in the absence of local codes, with the latest
edition of the National Electrical Code (ANSIINFPA 70).
A ground lug is provided for this purpose. Size the ground
ing conductor in accordance with Table 250-95 of the
National Electrical Code. Do not use the ground lug for
connecting a neutral conductor.
-
CAUTION
Conduit and fittings must be weather tight to avoid water
entry into the building.
4. Knockouts are provided at locations 3, 4, 5 and 6.
5. If an external field-supplied disconnect is used, the power
wiring will route as follows:
a. Power entry location other than location 8: Exit unit via
side location shown in Figures 16 and 17. Enter via a
disconnect box. Connect to the disconnect and leave the
disconnect box. Enter the unit again at the side location
shown in Figures 16 and 17.
b. Power entry at location 8: Exit the unit via base rail as
shown in Figure 9. Enter the disconnect box, connect to
the disconnect and then leave the disconnect box. Enter
the unit again at the side location shown in Figure 17.
It may be easier to penetrate the roof outside the curb versus
using Locations 7 and 8.
MAIN POWER WIRING
1. The main power supply for the RG/RE090 and 120 rooftops units shall be three phase, three wire. The unit is factory wired for the voltage shown on the unit's nameplate.
Note: If supply voltage is 208V, the lead on the primary of
transformer TRANS 1 must be moved from the
230V to the 208V tap.
2. Main power wiring should be sized for the minimum wire
ampacity shown on the unit's nameplate. Size wires in
accordance with the ampacity tables in Artical 310 of the
National 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.
WARNING
To avoid risk of fire and equipment damage, use copper
conductors only
3. A weather tight disconnect switch, properly sized for the
unit total load, must be field installed. A non-fused internal
disconnect can be used which fits into the unit at the loca
tions shown in Figures 16 and 17. Knockouts for mounting
the disconnect are provided in the exterior panels. An exter
nal, field-supplied disconnect may be mounted on the same
fixed exterior panel shown in Figures 16 and 17.
Note: Do not cover the nameplate with field supplied dis-
connect switch.
6. Connect power wiring to the main power terminal block.
This terminal block is located within the main control box
on units without electric heat (PB1) and within the electri
cal heat control box on units with electric heat (PB3).
7. Supply voltage to rooftop unit must not vary by more than
10% of the value indicated on the unit nameplate. Phase
voltage unbalance must not exceed 2%. Contact the local
power company for correction of improper voltage or
phase unbalance.
WARNING
Failure of unit due to operation on improper line voltage
or with excessive phase unbalance constitutes product
abuse that may cause severe damage to the unit's
electrical components and will void the unit warranty.
LOW VOLTAGE CONTROL WiRING
1. A 24V thermostat must be field installed. It may be purchased with the unit or field supplied. All cooling and heating systems available in Models RG/RE090 and 120 are 2stage. Thermostats may be programmable or electrome
chanical as required.
2. Locate the thermostat or remote sensor in the conditioned
space where it will sense average temperature. Do not
locate the device where it may be directly exposed to sup
ply air, sunlight or other sources of heat. Follow the installation instructions packaged with the thermostat.
3. Use #18 AWG wire for 24V control wiring runs not
exceeding 75 feet. Use #16 AWG wire for 24V control 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 National Electrical Code (NEC) Class 2
where permitted by local codes.
4. Route thermostat wires from the sub-base terminals to the
unit. Control wiring should enter through the unit base
frame as shown in Figure 18, or through the fixed side
panel as shown in Figures 16 and 17. Connect the thermo
stat and any accessory wiring to the low voltage terminal
block TB1 in the main control box as shown in Figure 19.
Note: Field supplied conduit may need to be installed
depending on unit/curb configuration.
-
Note: Use 18-gauge solid conductor wire when connecting
thermostat wires to the terminals on the sub-base.
DO NOT use wire that is larger than 18 gauge. A
transition to 18-gauge wire may be required before
entering the thermostat sub-base.
-
-
-
-
-
-
IM-806 Page 15
Page 16
Figure 19. RG/RE 090 Through 120
(Cooling Only, Gas Heat /Electric Heat)
THERMOSTAT
R
G
Y1
Y2
W1
W2
SEE NOTE
SEE NOTE
ROOFTOP
UNIT
TB1
R
G
Y1
Y2
W1
W2
Note: Connections between unit terminals 'W1" and "W2"
and the corresponding thermostat terminals "W1"
and "W2" are not required on cooling only units.
GAS SUPPLY PIPING
WARNING
Improper installation, adjustment, alteration, service or
maintenance can cause personal injury or property
damage. Refer to the user's information manual
provided with this furnace. For assistance or additional
information, consult a qualified installer, service agency
or the gas supplier.
LOCATION AND INSTALLATION
1. The gas supply piping location and installation on the rooftop unit must be in accordance with local codes or, in the
absence of locals codes, with the ordinances of the latest
edition of the National Fuel Gas Code (ANSI Z223.1). A
manual gas shutoff valve must be field-installed external to
the rooftop unit. In addition, a drip leg must be installed
near the inlet connection. A ground joint union connection
is required between the external shutoff valve and the unit
connection to the gas valve to permit removal of the burner
assembly for servicing. Locate the union near the gas valve
as shown in Figure 20. Route gas piping to the unit so that
it does not interfere with removal of access panels. Piping
must be supported and aligned to prevent strains or mis
alignment of the manifold assembly. Refer to Figure 20.
2. All units are furnished with standard female NPT pipe connections. Connection pipe sizes for RG090 and 120 units is
3/4" NPT on 195 and 225 MBH furnaces. The size of the
gas supply piping to the unit must be based on length of
run, number of units on the system, gas characteristics,
BTU requirement and available supply pressure. All piping
must be done in accordance with local codes or, in the
absence of local codes, with the latest edition of the
National Fuel Gas Code (ANSI Z223.1).
Note: The gas connection size at the unit does NOT estab-
lish the size of the supply line.
3. These units are designed for either natural or LP gas and
are specifically constructed at the factory for only one of
these fuels. The fuels are NOT interchangeable. However,
the furnace can be converted in the field from natural gas to
LP gas with the appropriate factory kit (LPW-06). Only a
qualified contractor, experienced with natural and propane
gas systems, should attempt conversion. Kit instructions
must be followed closely to provide proper and reliable
unit operation.
4. With all units on a common line operating under full fire,
the natural gas main supply pressure should be adjusted to
approximately 7.0" W.C., measured at the unit gas valve. If
the gas pressure at the unit is greater than 10.5" W.C., the
contractor must furnish and install an external-type positive
shutoff service pressure regulator. The unit will not func
tion satisfactorily if supply gas pressure is less than 5.5"
W.C. or greater than 10.5" W.C.
Note: A minimum horizontal distance of 48" between the
regulator and the furnace flue discharge is required.
5. With all units on a common line operating under full fire,
the LP gas main supply pressure should be at least 11.0",
W.C. and must be no greater than 13.0" W.C., measured at
the unit gas valve. The unit will not function satisfactorily
if the supply gas pressure is less than 11.0" W.C. or greater
than 13.0" W.C.
6. Seal all pipe connections with a pipe thread compound that
is resistant to the fuel used with the furnace. Use a soapy
water solution to check all joints for leaks. A 1/8" NPT
plugged tap is located on the entering side of the gas valve
for test gauge connection to measure the supply (main) gas
pressure. Another 1/8" tap is provided on the side of the
manifold for checking the manifold pressure.
CAUTION
The furnace and its individual shutoff valve must be
disconnected from the gas supply system during any
pressure testing of the system at test pressures in
excess of 1/2 psig (13.8" W.C.)
-
The furnace must be isolated from the gas supply
piping system by closing its individual manual shutoff
valve during any pressure testing equal to or less than
1/2 psig (13.8" W.C.).
CAUTION
7. There must be no obstruction to prevent the flow of combustion and ventilating air. A vent stack is not required and
must never be used. The power ventor will supply an ade
quate amount of combustion air as long as the air passageways are kept free of any obstructions and the
recommended external unit clearances are maintained.
(The wind shield must be in place during furnace opera
tion. See Exterior Wind Shield Installation).
-
-
-
Page 16 IM-806
Page 17
Figure 20. Gas Supply Piping
T
ld
CONDENSATE DRAIN CONNECTION
1. All units are equipped with a flexible tube condensate trap
which may be connected to either side of the drain pan as
shown in Figure 21.
Figure 21. Internal Condensate Drain Routing
4. Drain pans will have some moisture in them, so periodic
cleaning is necessary to avoid algae and fungus build-up,
which can plug the drain and cause the drain pan to over
flow.
EXTERIOR WIND SHIELD
INSTALLATION
Details of exterior wind shield installation are as follows:
Figure 22. Exterior Wind Shield
-
op Panel
A
D
C
E
CAUTION
To avoid condensate build-up and equipment damage,
the end of the tube must be routed through the
insulation and the top of the base rail so that the
condensate has free access to the roof or external
drainage system. Knockouts are provided in the base
rails. The unused hole on the opposite side of the drain
pan must be blocked with the plug provided.
2. Drainage of condensate directly onto the roof may be
acceptable; refer to local code. Provide a small drip pad of
either stone, mortar, wood or metal to avoid damage to the
roof.
3. If condensate is to be piped into the building drainage system, the drain line must penetrate the roof external to the
unit. Refer to local codes for additional requirements. The
flexible tube condensate trap may be connected to an exter
nal drain line with a hose clamp.
-
Table 7: Exterior Wind Shield Dimensions
ModelABCDE
090, 1201 1/2"11 "3 1/2"8 1/4"2 1/8"
Compressor Access Panel
B
Outer Shie
Inner Shield
Gas Access Panel
IM-806 Page 17
Page 18
CHECK, TEST AND START
PROCEDURES
WARNING
Electric shock can cause severe injury or death. Bond
the frame to the building electrical ground with the
grounding terminal provided. Disconnect electric power
before servicing equipment. Service must be performed
by qualified personnel only.
• All electric power, gas, hot water or steam line connections, and the condensate drain installation have been completed for each unit on the job. These main supply lines
must be functional and capable of operating all units simul
taneously.
PRELIMINARY IN BUILDING
Prior to the beginning of Check, Test & Start procedures on the
roof, complete the following steps.
-
BEFORE STARTUP
WARNING
Disconnect power to the unit and padlock in the "off"
position before servicing the fans. Moving fans can
cause severe personal injury or death.
This procedure has been prepared as a guide for the proper
Check, Test & Start of the rooftop unit. The Check, Test &
Start procedure provides a step-by-step sequence which, if fol
lowed, will provide the proper startup of the equipment in the
minimum amount of time. Air balancing of duct system is not
considered part of the Check, Test & Start of the roof top unit.
However, it is an important phase of any air conditioning sys
tem startup and should be performed upon completion of the
Check, Test & Start procedure. The Check, Test & Start proce
dure at outside ambient temperatures below 55°F should be
limited to a readiness check of the refrigeration system. The
required final check and calibration should be completed when
the outside ambient rises above 55°F
TOOLS REQUIRED TO PERFORM CHECK, TEST &
START
1. Refrigeration gauge and manifold.
2. Voltmeter.
3. Clamp-on ammeter.
4. Ohmmeter.
5. Test lead. Minimum #16 AWG with insulated alligator
clips.
6. Manometer for verifying gas pressure from 0" to 20" W.C.
7. Air temperature measuring device.
8. General refrigeration mechanic tools.
TEMPORARY HEATING OR COOLING
If it is planned that the unit will be used for temporary heating
or cooling, the Check, Test & Start must first be performed in
accordance with this bulletin. Failure to comply with this
requirement will void the warranty. Install new filters after the
machines are used for temporary heating or cooling, and the
coils, fans, and motors must be checked for unacceptable lev
els of construction dust and dirt.
CONTRACTOR RESPONSIBILITY
The installing contractor must verify that:
WARNING
With the disconnect on and the thermostat not satisfied,
the machine will run. To avoid equipment damage, fire
or personal injury, do not start the machine until all the
necessary prechecks and tests have been performed.
1. THERMOSTAT. Set the thermostat in the conditioned
space at a point at least 10°F below the zone temperature.
On cooling only models, set the thermostat system switch
on COOL and the fan switch on AUTO. On heating/cool
ing models, set the thermostat system switch on AUTO and
the fan switch on AUTO.
2. NIGHT SETBACK THERMOSTAT (OPTIONAL). Set
thermostat at a point at least 10°F below the zone tempera
-
ture.
CHECK OF ROOF CURB INSTALLATION
Check the proper installation of the unit on the roof curb. Note
any deficiencies in a separate report and forward it to the con
tractor. The unit and curb assembly should be installed level.
The flashing of the roof mounting curb to the roof should be
checked, especially at the corners, for good workmanship.
CHECK FOR MINIMUM CLEARANCES
A minimum of 36" clearance must be provided on the main
control box side of the unit. A minimum of 48" clearance is
recommended on all other sides. A clearance of 75" is desir
able on the control box side for removal of the fan shaft or
heating section. The outside air intake must be remote from all
building exhausts. The condenser air intake (if used) must be
remote from all exhausts to provide full condenser capacity.
DANGER
CARBON MONOXIDE (CO) POISONING HAZARD
CO can cause brain damage and death. It is odorless
and colorless. Do not install this unit in any enclosure
or location where fumes many enter an enclosure.
CHECK AND REPORT DAMAGE
Itemize damaged or missing parts, if any, in a separate report
stating what action has been initiated by the Contractor to cor
rect them. The absence of this information will mean that the
unit was complete and in good condition on the date of the
Check, Test & Start.
• All supply and return air ductwork is in place and corresponds with installation instructions.
• All thermostats are mounted and wired in accordance with
installation instructions.
Page 18 IM-806
Page 19
CHECK FOR OBSTRUCTIONS, FAN CLEARANCE
AND WIRING
During the performance of the Check, Test & Start procedure,
you will work in the various sections of the unit. It is important
that you remove extraneous construction and shipping materi
als that may be found during this procedure. Rotate all fans
manually to check for proper clearances, and to verify that
they rotate freely. Check bolts and screws that may have jarred
loose during shipment to the jobsite. Re-tighten all electrical
connections.
PRE-START-UP PRECAUTIONS
It is important that the unit has been properly grounded during
installation. Before start-up, check the ground lug connection
in the main control box for tightness, and closing the circuit
breaker or disconnect switch. Verify that the supply voltage on
the line side of disconnect agrees with the voltage on the unit
nameplate, and that it is within the utilization voltage range as
indicated in Table 8.
Table 8: Utilization Voltage Range
System VoltageNameplate
208-230/60/3208/230187253
480/60/3460414506
Utilization Voltage
Min.Max.
System Voltage - That nominal voltage value assigned to a
circuit or system for the purpose of designating its voltage
class.
Nameplate Voltage - That voltage assigned to a piece of
equipment for the purpose of designating its voltage class and
for the purpose of defining the minimum and maximum volt
age at which the equipment will operate.
Utilization Voltage - The voltage of the line terminals of the
equipment at which the equipment must give fully satisfactory
performance. Once it is established that the supply voltage will
be maintained within the utilization range under all system
conditions, check and calculate to see if an unbalanced condi
tion exists between phases. Calculate the percent voltage
unbalance as follows:
PERCENT VOLTAGE
UNBALANCE 3
HOW TO USE THE FORMULA:
EXAMPLE: With voltage of 220, 216, and 213
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%.
= 100 X
MAXIMUM VOLTAGE DEVIATIONS
FROM AVERAGE VOLTAGE
AVERAGE VOLTAGE
4
216
2
1
400
216
CHECK FIELD DUCT CONNECTIONS
Verify that all duct connections are tight and that there is no air
bypass between the supply and return.
CONTROL SYSTEM CHECK, TEST &
-
START PROCEDURE
CONTROL VOLTAGE CHECK
With the disconnect switch in the open "OFF" position, disconnect blue wire from the low voltage transformer TRANS1.
Close the disconnect switch to energize the TRANS1 control
transformer. Check the primary and secondary (24V) of con
trol transformer TRANS1.
THERMOSTAT PRELIMINARY CHECK
With disconnect switch open and blue wire disconnected from
the TRANS1 transformer, attach one lead of ohmmeter to ter
minal R on the TB1 terminal block. Touch, in order, the other
ohmmeter lead to terminals Y1, Y2 and G at the TB1 terminal
block. There must be continuity from terminal R to terminals
Y1, Y2 and G. R to Y1 indicates first stage cool. R to Y2 indi
cates second stage cool. R to G indicates fan (auto). Replace
the blue wire on TRANS1 transformer.
ECONOMIZER DAMPERS & FILTERS
CHECK, TEST & START
FILTER SECTION CHECK
Remove the filter section access panels and check that the filters are property installed. Note the airflow arrows on the filter
frames.
-
Figure 23. Filter Access
-
-
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IM-806 Page 19
Page 20
EVAPORATOR BLOWER FAN
CHECK, TEST & START
PROCEDURE
ECONOMIZER & DAMPER SECTION CHECK
Follow instructions in the accessory for check, test & start procedures.
BEARING CHECK
Prior to energizing any fans, verify that all setscrews are tight
so that the bearings are property secured to the shafts.
SET EVAPORATOR FAN RPM
Actual RPM's must be set and verified with a tachometer or
strobe light. Refer to Tables 9 and 10 for basic unit fan RPM.
Refer also to the "Air Balancing" section of this manual. With
the disconnect switch open, disconnect the thermostat wires
from terminals Y1, Y2, W1 and W2 to avoid heating and
mechanical cooling from coming on. Place a jumper wire
across terminals R and G at the TB1 terminal block. Close the
disconnect switch. The evaporator fan motor will operate so
that the RPM can be checked.
CAUTION
To avoid overheating and equipment damage, airflow
must be adjusted so that the temperature rise does not
exceed 40°F on electric heat units with 70°F entering
air.
For gas heat units, the airflow must be adjusted so that the air
temperature rise falls within the ranges given in Table 11.
DO NOT SELECT IN SHADED AREAS (FOR INTERPOLATION ONLY)
1. Selections in BOLD ITALICS require a field drive change. See Table 8 for drive ranges.
2. Selections below heavy line require oversize motor.
3. Maximum fan RPM = 1500
4. Table Includes all internal pressure drops induding cabinet losses. See the product catalog for additional pressure drops that must
be considered as part of external static pressure drop.
5. Refer to catalog for fan curves.
Table 10: Supply Fan RPM Range
Motor Sheave
Model
090Fan RPM1.5 HP Motor1209114610821018955891
120Fan RPM3.0 HP Motor12421186112910731016960
NOTE: Allow ± 5°/o Variation in blower RPM due to pulley manufacturing tolerances
Fan Sheave Fixed
Motor Sheave - Turn Open012345
Table 11: Condenser Fan Motors
ModelQuanityHorsepower
09021/22.61.3
12021/22.61.3
NOTE: All values are per compressor
208-230/60/3460/60/3
FLA
Adjustable Factory Setting 2 Turns Open
Page 20 IM-806
Page 21
Table 12: Evaporator Fan Motors
Model195225NOTES:
Number of Tubes67
Ventor Motor HP1/161/12
BTUH Input193,000225,000
BTUH Output154,000180,000
260055.0-
280051.1-
300047.755.6
320044.752.1
340042.149.1
CFM
360039.746.3
3800-43.9
4000-41.7
4200-39.7
4400-37.9
4600-36.3
DRIVE BELT
TENSION AND ALIGNMENT ADJUSTMENT
Check the drive for adequate run-in belt tension. Correct belt
tension is very important. A loose belt will have a substantially
shorter life, and a belt that is too tight may cause premature
motor and bearing failure. Correct belt tension on these units
can be checked by measuring the force required to deflect the
belt 1/8" at the midpoint of the span length (Figure 24). Belt
tension force can be measured using a belt tension checker,
available through most belt manufacturers. The correct deflec
tion force is 5 lbs. for a new belt and 3.5 lbs. for a belt that has
been run in. New belt tension includes initial belt stretch.
When new V-belts are installed on a drive the initial tension
will drop rapidly during the first few hours. Check tension fre
quently during the first 24 hours of operation. Subsequent
retensioning should fall between the minimum and maximum
force. To determine the deflection distance from the normal
position, use a straightedge or stretch a cord from sheave to
sheave to use as a reference line. On multiple belt drives, an
adjacent undeflected belt can be used as a reference.
Figure 24. Drive Belt Tension Adjustment
S
P
A
N
L
E
N
G
T
H
(
t
D
E
F
L
E
C
F
O
R
C
D
C
)
T
I
O
N
E
h
d
1. Capacities are approved for altitudes to 2000 feet. At higher elevations, heating
capacity must be reduced 4% (xO.96) for each 1000 feet above sea level,
2. AIr temperature rise is for total heating capacity. Temperature rises at other
conditions may be calculated by using the formula:
Temperature Rise =
3. For altitudes over 2000 feet. air temperature rise must be calculated using the
formula:
Temperature Rise =
4 Two-stage control is standard.
5. Output capacity based on nominal 1000 Btu/FI' natural gas or 2500 BtuIFt3
propane.
6. See nameplate data for maximum air temp. flse for specific unit.
Output Capacity (BTIJH)
1.08 x CFM (Airflow)
Output Capacity (BTUH)
14.4x CFM (Airflow) X Density of Air (LbsJCu.Ft)
Table 13: Recommended Pounds of Force Per Belt
Belt
Section
A
Small
Sheave Dia.
(in.)
32.0 - 3.02.3 - 3.52.4 - 3.62.6 - 3.9
42.6 - 3.92.8 - 4.23.0 - 4.53.3 - 5.0
53.0 - 4.53.3 - 5.03.4 - 5.13.7 - 5.6
11.524.0 & Over
Min. - Max Min. - Max Min. - Max Min. - Max
Drive Ratio
EVAPORATOR FAN ROTATION CHECK
Verify that the fan rotates clockwise when viewed from the
drive side of unit, and in accordance with rotation arrow
shown on blower housing. If it does not, reverse the two
incoming power cables at PB1 terminal block and repeat the
bearing check.
Do not attempt to change the load side wiring. Internal wiring
is set so that all motors and compressors will rotate in the cor
rect direction once the evaporator fan motor rotation check has
been made.
ELECTRICAL INPUT CHECK
Make a preliminary check of evaporator fan ampere draw and
verify that the motor nameplate amps are not exceeded. A final
check of the amp draw should be made when air balancing of
the duct system is complete.
Table 14: Evaporator Fan Motors
Horsepower
1.54.2/4.62.1
38.4/8.64.2
208-230/60/3460/60/3
FLA
RESTORING CONNECTIONS
With disconnect switch open, remove the jumper wire from
terminals R and G at the TB1 terminal block, and reconnect
the thermostat wires to terminals V1, Y2, W1 and W2.
-
t = Span Length, inches
C = Center Distance, inches
D = Large Sheave Diameter, inches
d = Small Sheave Diameter, inches
h = Deflection Height, inches
IM-806 Page 21
Page 22
REFRIGERATION SYSTEM
CHECK, TEST & START PROCEDURE PRELIMINARY CHECK
Verify that the hold-down bolts on the compressors are secure
and have not vibrated loose during shipment. Check to see that
vibration grommets have been installed. Visually check all pip
ing and clamps. The entire refrigeration system has been factory charged and tested, making it unnecessary to field charge.
Factory charges are shown in Table 15 and on the unit name
plate.
Table 15: Refrigerant Charge Per Circuit
RG/RECharge (oz.)
090115
120150
Install service manifold hoses. Gauges should read a saturation
pressure corresponding to the ambient temperature. The charge
should be checked to obtain 12° to 15° of sub-cooling per sys
tem (i.e. compressor circuits).
REFRIGERATION SEQUENCE CHECK
With the disconnect switch open, remove the field connected
thermostat wire from terminal R on the TB1 terminal block.
Place a jumper across terminals R and G, and across R and V1
on the TB1 terminal block. Close the disconnect switch. The
following operational sequence should be observed.
1. Current through the primary winding of transformer
TRANS1 energizes the 24-volt control circuit.
2. The first stage of cooling is energized when the room temperature is above the thermostat set-point. The thermostat
makes R to G and R to V1.
a. Supply contactor BC is energized.
b. UNITS WITHOUT ECONOMIZER OPTION: The
first stage compressor circuit is energized through lowpressure switch LP1, high pressure switch HP1, and
optional Freezestat. Compressors all rotate in the proper
direction. Verification of the correct supply fan rotation
at initial startup will also indicate correct compressor
rotation. Reconnect the power and check for proper
operation.
c. UNITS WITH ECONOMIZER OPTION: The first
stage of cooling is interlocked through terminal 1 and 2
on the economizer module. Control power must be
available to the damper motor DM through terminal
ECON on terminal block IIC (refer to economizer
instructions). If the outdoor enthalpy is not suitable for
cooling, the economizer module terminals will be
closed, permitting the compressor circuit to be ener
gized.
3. Contactor BC closes its contacts L1, L2 and L3 to T1, T2
and T3 to provide power to the supply fan motor (refer to
"Evaporator Blower Fan Check, Test & Start Procedure").
Check the supply fan rotation. If the supply fan is rotating
in the wrong direction, disconnect and lock-off power
block PB1. Do not attempt to change load side wiring.
Internal wiring is set at the factory so that the supply fan
and compressors all rotate in the proper direction. Verifica
-
-
-
-
-
tion of correct supply fan rotation at initial startup will also
indicate correct compressor rotation. Reconnect power and
check for proper operation.
4. Contactor C1 closes its contacts L1, L2 and L3 to
LT1, T2 and T3 to provide power to the compressor
motor COMP.1. In addition, contactor C1 closes its
contact L3 to T4 , energizing all of the condenser fan
motors.
5. Check that the compressors are operating correctly. The
scroll compressors in these units must operate in the proper
rotation. Check the compressor discharge line pressure or
temperature.
CAUTION
To avoid personal injury, do not touch the discharge line
because it may be hot.
After each compressor is started, the discharge pressure and
discharge line temperature should increase. If this does not
occur, and if the compressor is producing an exceptional
amount of noise, the compressor motor may be operating in
the wrong direction. If a problem is encountered, it will be nec
essary to check all of the compressors and the supply fan
motor. If a single motor is operating backward, check the
power wiring for that motor and correct any leads that have
been interchanged at the contactor or at the motor. If all of the
motors are operating backward, disconnect the unit power sup
ply and lock it in the "OFF" position. Switch the two leads of
the power supply at the unit power terminal block PB1. Recon
nect power and check for compressor and supply fan motor
operation.
6. To simulate a second stage call for mechanical cooling
from the wall thermostat, place a jumper across terminals R
and Y2 of terminal block TB1. The second stage of cooling
is energized when the room temperature is above the ther
-
mostat set-point for both first and second stages of cooling.
The thermostat makes R to Y2.
a. UNITS WITHOUT ECONOMIZER OPTION: The
second stage compressor circuit is energized through the
low pressure switch LP2, high pressure switch HP2, time
delay llC (pin 11 & 12) and optional freezestat.
b. UNIT WITH ECONOMIZER OPTION: The second
stage compressor circuit is interlocked through terminals
3 and 4 of the economizer module (refer to 2c under
Refrigeration Sequence Check). If the outdoor air
enthalpy is not suitable for cooling, the economizer ter
-
minals will be closed, permitting compressor circuit 2 to
be energized.
7. Contactor C2 closes its contacts L1, L2 and L3 to T1, T2
and T3 to provide power to the compressor motor
COMP. 2. In addition, contactor C2 closes its contact L3
to T4 duplicating the power circuit to all of the con
-
denser fan motors, allowing condenser air for compressor circuit 2 to operate (if compressor circuit 1 is
tripped).
Page 22 IM-806
Page 23
8. With all unit protective devices closed, the system will continue cooling operation until the thermostat is satisfied.
9. Disconnecting the jumper wire between R and Y2 on TB1
terminal block will simulate a satisfied second stage of the
thermostat. The second stage compressor will cycle off and
11C (pin 12) will initiate its time delay cycle.
10.Disconnecting the jumper wire between R and Yl and
between R and G on TB1 terminal block will simulate a
satisfied first stage of the thermostat. The first stage com
-
pressor and the supply fan will cycle off.
11.After a time delay of approximately 3 minutes, the second
stage compressor control circuits will be ready to respond
to a subsequent call for cooling from the wall thermostat.
12.Open the disconnect switch. Reconnect the field thermostat
wire at terminal R on terminal block TB1.
REFRIGERATION PERFORMANCE CHECK
Under normal summertime (full load) operating conditions,
superheat should be between 8°F and 12°F. Sub-cooling, mea
sured at the condenser outlet, should be 15°F (nominal). A
25°F to 35°F temperature difference should exist between the
entering condenser air and the temperature corresponding to
the compressor saturated discharge pressure. The adjustable
expansion valves can be used to obtain the proper subcooling
setting. This is factory set and should not need to be used
unless operation is unsatisfactory. Check to see that the com
pressor RLA corresponds to the values shown in Table 16.
RLA draw can be much lower than values in Table 16 at low
load conditions and low ambient condensing temperatures.
Values in Table 16 can be slightly exceeded at high load condi
tions and high ambient condensing temperatures.
Table 16: Compressor RLA and LRA
RG/REQty.HP
09022.912.5885.944
12023.917.41236.849.5
208-230/60/3460/60/3
RLALRARLALRA
GAS HEAT CHECK, TEST & START
PROCEDURE
WARNING
If overheating occurs or the gas supply fails to shut off,
turn off the manual gas valve off before shutting off the
electrical supply to avoid fire, explosion, personal injury
or death.
GAS SUPPLY PRESSURES & REGULATOR
ADJUSTMENTS
The first step in checking out the gas-fired furnace is to test the
gas supply piping to the unit for tightness, and to purge the
system of air using methods outlined in the latest edition of the
National Fuel Gas Code (ANSI Z223.1). Verify that the dis
connect switch is in the "OFF" position. Use a soapy water
solution to check for gas leaks. Since the unit must be subject
to considerable jarring durring shipment, it is extremely impor
tant that all gas connections and joints be tested for tightness.
Check gas piping downstream from the unit inlet for leaks dur
ing the subsequent sequence check.
Adjust the supply gas pressure to 7.0" W.C. for natural gas and
11.0" W.C. for propane gas, with the gas burners operating. If
there is more than one unit on a common gas line, the pres
sures should be checked with all units under full fire. A supply
pressure tap is provided on the upstream side of the gas valve.
A manifold pressure tap is provided on the manifold as shown
in Figure 20. The normal manifold pressure for full input is
3.5" W.C. for natural gas and 9.5" W.C. for propane gas. Mini
mum gas supply pressure is 5.5" W.C. for natural gas and 11.0"
W.C. for propane gas. In order to obtain rating, the gas supply
pressure must be 11.0" W.C. for propane gas. The pressure reg
ulator on propane gas models is adjusted for 9.5" W.C. manifold pressure and is intended only to prevent over-firing. Do
not attempt adjustment of the built-in pressure regulator unless
the supply pressure is at least 7.0" W.C. on natural gas or 13.0"
W.C. on propane gas. Check the location of the ignition elec
trode and the flame sensor for correct gap setting. Refer to Figure 25 and Tables 17 and 18. Because gas appliances located
more than 2000 feet above sea level must be derated 4% per
1000 feet of total elevation, and because variance in the gas
heating value and specific gravity require a change in manifold
pressure to obtain rating, it is mandatory that the input be
adjusted at the installation site. All installations must be made
as outlined in the latest edition of the National Fuel Gas Code
ANSI Z223.1. Follow the section entitled "Procedures To Be
Followed To Place An Appliance in Operation". Refer also to
the "User's Information Manual" supplied with the unit for
additional information on the gas furnace.
Figure 25. Ignition Electrode and Flame Sensor
11/16 ±1/32
5/8±1/32
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-
-
-
-
-
-
WARNING
To avoid fire, explosion, personal injury or death, do not
fire the gas furnace with the flue box cover removed.
CAUTION
Except during brief periods, when gas pressures are
being measured by qualified service personnel, the
furnace access panel must always be secured in place
when the furnace is in operation. An inspection port in
the access panel is provided to monitor the flame.
IM-806 Page 23
1/8±1/32
Page 24
Table 17: Heat Exchanger Specifications
Maximum Input BTUHNumber of Burners
193,000632,200
225,000732,000
Table 18: Burner Orifice Specification
Gas Furnace
No. of Tubes
6, & 836 (. 111")58 (.042")52 (.070")73 (.024")
Main Orifices
Drill Size Number (Dia.)
Natural GasLP Gas
Carryover
Orifices
Maximum BTUH Per
Burner
Main Orifices
Carryover
Orifices
SEQUENCE OF OPERATION - GAS HEATING
1. This unit has one Manual Reset Limit Control. 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.
2. If the ventor motor comes on, but the unit does not attempt
ignition, check if the ALS Automatic Reset High Limit
Control requires resetting.
3. With electricity and gas turned on, the system switch in the
"HEAT" or "AUTO" position and the fan switch in the
"AUTO" position, the thermostat will dose the circuit
between unit terminals R and W1 (R-W1) when the tem
perature falls below the thermostat setting.
4. D1 on 11C energizes relay IDMR.
5. Relay IDMR energizes the ventor motor IDM.
6. Operation of the ventor motor closes the centrifugal switch
ES located in the ventor motor. Unless excessive tempera
tures or shipping shock have opened high limit control
ALS, power is fed to the integrated ignition control, which
then initiates a 15-second pre-purge time delay. During this
period, the ventor motor will clear the combustion chamber
of any residual gas.
7. After the pre-purge period, the ignition control energizes
the first stage operator (Wl-C) on the gas valve and simul
taneously initiates a "3-try" spark ignition sequence.
8. When the burners are ignited, a minimum 4 micro-amp DC
current will flow through the flame between the sensor
electrode and the grounded burner.
9. When the controller proves that the flame has been established, it will keep the gas valve energized and discontinue
the ignition spark. First stage manifold pressure will be
approximately 1.6" W.C. for natural gas and 4.5" W.C. for
propane.
10.If the control is unable to ignite the burners after its initial
attempt, it will initiate another purge and spark sequence. A
third purge and spark sequence will be initiated if the sec
ond attempt is unsuccessful. If the third attempt is unsuccessful, the controller will close the gas valve and lock
itself out. It may be reset by momentarily interrupting
power. This may be accomplished by briefly lowering the
room thermostat set-point below room temperature, or by
shutting off the main power to the unit.
11.Integrated ignition control will close its normally open contacts after a delay of approximately 30 seconds. This action
energizes contactor BC and starts the supply fan motor.
Operation of the supply fan circulates air across the heat
exchanger and delivers heated air to the conditioned space.
12.In the event that the temperature at the thermostat continues
to fall, the thermostat will also close the contact between
terminals R and W2. This will energize the second stage of
the gas valve (W2-C). After a delay of about 30 seconds,
the gas manifold pressure will increase to approximately
3.5" W.C. for natural gas and 9.5" W.C. for propane.
13.When the space temperature rises, the thermostat will first
open R-W2 and finally R-W1. Opening R-W1 will cause
the gas valve to close and the furnace to shut down.
14.The furnace has three high temperature limit controls,
which can shut down the burner. They do not shut down the
ventor motor.
LS Automatic Reset High Limit Control
Located in the blower compartment next to the rear blower, its
sensing element projects through the blower section bulkhead
and senses the temperature at the rear of the furnace. It will
cycle the furnace off if the temperature exceeds 100°F plus
maximum rise.
ALS Automatic Reset High Limit Control
Located next to LS in the blower compartment, it senses air
temperature within the blower compartment and protects the
-
filters from excessive temperature. It will shut down the fur
nace if it senses excessive temperatures.
RS Manual Reset Flame Rollout Control
Located in the burner compartment on the top shelf behind the
ventor motor, it senses high temperature that could occur if the
heat exchanger tubes were plugged and the flame was rolling
out instead of entering the tubes. It has a manual push-button
reset that cannot be actuated until the limit control has cooled.
INPUT RATING
It is the responsibility of the contractor to adjust the gas input
to the unit. The input rate can be calculated by using the for
mula:
INPUT Btu/Hr =
3600 X HV
T
WHERE:
HV = Heating value of fuel = Btu/ft3 of gas
T = Time in seconds per ft3 of gas flow as read from gas meter
Adjust input rate by varying the adjustment of the gas pressure
regulator on the gas valve (see Figure 26). All adjustments
must be made with the furnace operating at high fire and at
normal operating temperature. Clockwise rotation of the pres
sure regulator screw increases pressure and gas flow rate. Turn
the screw counterclockwise to decrease the pressure and gas
flow rate. After adjustment, the furnace temperature rise must
-
be within the range specified on the unit nameplate.
Note: Thermal efficiency of the furnace is a product effi-
ciency rating determined under continuous operating conditions independent of any installed system.
CAUTION
Do not exceed input rating or manifold pressure values
on the unit nameplate. If the input rating on the
nameplate cannot be attained without exceeding the
listed manifold pressure, contact your local service
representative.
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Page 24 IM-806
Page 25
Figure 26. Pressure Adjustments
B
AIR BALANCING
The drive on the supply fan is typically set in the middle of the
RPM range. The drive motor sheave pitch diameter is fieldadjustable for the required airflow (refer to "Drive Adjust
-
ments").
When the final adjustments are complete, check the current
draw of the motor and compare it to the full load current rating
of the motor. The amperage must not exceed the service factor
stamped on the motor nameplate. The total airflow must not be
less than that required for operation of the electric heaters or
the furnace.
Check the operating balance with the economizer at full outside air and at minimum outside air. Upon completion of the
air balance, it is a common industry practice that the variable
pitched motor sheave be replaced with a properly-sized fixed
sheave. A matching fixed sheave will provide longer belt and
bearing life. Initially, it is best to have a variable pitched motor
sheave for the purpose of air balancing, but once the balance
has been achieved, fixed sheaves maintain alignment and min
-
imize vibration more effectively.
DRIVE ADJUSTMENTS
MOUNTING & ADJUSTING MOTOR SHEAVES VL,
VM & 2VP VARIABLE PITCH KEY TYPE SHEAVES
MOUNTING:
1. Mount all sheaves on the motor or driving shaft with the set
screw "A" toward the motor.
2. Verify that both driving and driven sheaves are in alignment and that shafts are parallel.
3. Fit internal key "C" between the sheave and shaft, and lock
set screw "A" securely in place.
ADJUSTING VL & VM SHEAVES:
1. Loosen set screw "B" (5/32" Allen key).
2. Adjust sheave pitch diameter for the desired speed by opening the moving part by half or full turns from closed position. DO NOT OPEN MORE THAN FIVE FULL
TURNS.
3. Securely tighten set screw "B" over flat.
AFTER ADJUSTING:
1. Put on belts and adjust belt tension. DO NOT FORCE
BELTS OVER GROOVES.
2. Future adjustments should be made by loosening the belt
tension and increasing or decreasing the pitch diameter of
the sheave by half or full turns as required. Readjust belt
tension before starting drive.
3. Be sure that all keys are in place and that all set screws are
tight before starting drive. Check set screws and belt ten
sion after 24 hours service.
Figure 27. Motor Sheave Adjustment
A
C
VL & VM
Do not operate the sheave with the flange projecting beyond
the hub end.
MAINTENANCE
WARNING
Improper installation can cause equipment damage,
severe personal injury or death. Installation and
maintenance must be performed only by qualified
personnel who are familiar with local codes and
regulations and experienced with this type of
equipment.
CAUTION
Avoid sharp edges and coil surfaces because they are
potential injury hazards.
Planned maintenance is the best way to avoid unnecessary
expense and inconvenience. Have this system inspected at reg
ular intervals by qualified service personnel, at least twice a
year. Routine maintenance should cover the following items:
1. Tighten all belts, set screws, and wire connections.
2. Clean evaporator and condenser coils mechanically or with
cold water, if necessary. Any fouling is normally matted on
the entering air face of the coil and can be removed by
brushing.
3. Lubricate motor bearings (see Lubrication).
4. Align or replace belts as needed.
5. Replace filters as needed (see Filters).
6. Check for blockage of the condensate drain.
7. Check power and control voltages.
8. Check running amperage.
9. Check operating temperatures and pressures.
10.Check and adjust temperature and pressure controls.
11.Check and adjust damper linkages.
12.Check operation of all unit protective controls.
13.Examine gas furnaces (see "Inspection and Cleaning).
14.Check condenser fans and tighten set screws.
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IM-806 Page 25
Page 26
FILTERS
Different applications can require that filters be replaced at different intervals. Filters must be replaced at least every three (3)
months during operating seasons.
Filters supplied with the units are the disposable type and are
as follows:
Table 19: Filters
Unit SizeQuantityFilter Size
090325 x 25 x2B13696-12
120
316 x 25 x2B13696-10
320 x 25 x2B13696-11
Part No.
(One Filter)
LUBRICATION
The fan shaft bearings, the 1 to 3 HP supply fan motors, and
the condenser fan motors are permanently lubricated. For
lubrication of the compressors, use Suniso 3GS, Texaco
WF32, or Calumet ROl5 oils. All three oils are compatible if
mixed, and are suitable for both high and low temperature sys
tems.
CAUTION
Excessive grease will overheat the bearings. Use only a
high grade lithium base grease with a 200°F operating
temperature.
Note: Specific greasing instructions may be found on a tag
attached to the motor. If special lubrication instruc
tions are shown on the motor nameplate, they will
supersede all other instructions.
VENTOR MOTOR
To lubricate the ventor motor, remove the furnace access
panel. Lubricate the motor in two locations as shown in Figure
28. Use SAE 20W lubricant and add five (5) drops to each
location. The motor should be lubricated at the beginning of
each heating season. Do not over lubricate
.
CAUTION
Do not drip oil on the gas valve. The oil may damage
the non-metallic parts and render the valve inoperative.
Remove any oil residues from the burner compartment.
Figure 28. Ventor Motor
INSPECTION & CLEANING
All flue product carrying areas of the furnace, its vent system,
and main burners should be examined by a qualified service
agency before the start of each heating season. This examina
tion is necessary for continued proper operation. Particular
attention should be given to deterioration from corrosion or
other sources. This examination is accomplished in the follow
ing manner.
1. Disconnect power to the unit and remove the furnace section access panel.
2. Refer to Figure 29. Remove burner assembly:
a. Disconnect the three wires from the gas valve after not-
ing which wires are connected to each terminal.
b. Disconnect wires from the flame rod and ignition elec-
trode.
c. Disconnect the gas piping at the union.
-
-
d. The entire burner assembly can now be removed from
the unit. Note how the front of the burner assembly
nests around wide location tabs, one at the top and one
at the bottom.
3. Remove the flue box cover. The cover consists of two
pieces which can be removed as a single unit. Remove
the flue baffle.
4. Remove the turbulator from within each heat exchanger
tube. The end corner of the turbulator mates with the
groove at the tube end seam. To release the turbulator, grip
the end of the turbulator with a pliers, force the corner
away from the groove, and pull the turbulator out of the
tube.
5. Inspect the burner assembly, the heat exchanger tubes, the
turbulators, the flue box, the ventor fan and the ventor fan
outlet openings for accumulations of soot and deterioration.
Soot can be removed with a flexible wire brush. The inside
of the tubes can be cleaned with a boiler tube type wire
brush. If the bends of the tubes must be cleaned, remove
the plate surrounding the burner end of the tubes. A brush
or steel wool can then be pulled through the tube with a
cable. Be cautious not to damage the corrosion resistant
coating on the various metal parts. Remove all residue.
6. If deterioration is evident, contact a qualified service
agency. Minor deterioration of the turbulator ends is not
cause for concern.
7. Upon completion of inspection and cleaning, replace all
parts in the reverse order in which they were removed.
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-
CAUTION
Use all screws that were removed; they are necessary
for proper operation of the unit.
8. Inspect and periodically clean the vent outlet (bird screen)
on the access panel.
Note: Periodic observation of the flame through the
inspection port and a log of C0
measurements are
2
recommended. This will aid in determining whether
the furnace is operating efficiently, or if the furnace
requires cleaning.
Page 26 IM-806
Page 27
Figure 29. Gas Fired Furnance
IM-806 Page 27
Page 28
Page 28 IM-806
Page 29
This document contains the most current product information as of this printing. For the most up-to-date
product information, please go to www.mcquay.com.
www.mcquay.com • 800-432-1342
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