Modine Manufacturing HBP Manual

January, 2020
INSTALLATION AND SERVICE MANUAL
indirect gas-fired weatherproof make-up air units
models HBP/HCP/HDP/HPP
OBP/OCP/ODP/OPP
5-572.10
5H0762330001
THIS MANUAL IS THE PROPERTY OF THE OWNER.
PLEASE BE SURE TO LEAVE IT WITH THE OWNER WHEN YOU LEAVE THE JOB.
All models approved for use in California by the CEC.
FOR YOUR SAFETY
The use and storage of gasoline or other
flammable vapors and liquids in open containers
in the vicinity of this appliance is hazardous.
FOR YOUR SAFETY
IF YOU SMELL GAS:
1. Open windows.
2. Don’t touch electrical switches.
3. Extinguish any open flame.
4. Immediately call your gas supplier.
Inspection on Arrival
1. Inspect unit upon arrival. In case of damage, report it
immediately to transportation company and your local
factory sales representative.
2. Check rating plate on unit to verify that power supply meets
available electric power at the point of installation.
3. Inspect unit upon arrival for conformance with description of
product ordered (including specifications where applicable).
IMPORTANT
The use of this manual is specifically intended
for a qualified installation and service agency.
A qualified installation and service agency
must perform all installation and service of
these appliances.
CAUTION
To prevent premature heat exchanger failure
do not locate ANY gas-fired units in areas
where chlorinated, halogenated, or acid
vapors are present in the atmosphere.
WARNING
1. Improper installation, adjustment, alteration,
service or maintenance can cause property
damage, injury or death, and could cause
exposure to substances which have been
determined by various state agencies to
cause cancer, birth defects or other
reproductive harm. Read the installation,
operating and maintenance instructions
thoroughly before installing or servicing this
equipment.
2. Installing, starting up and servicing heating,
ventilation and air conditioning equipment
poses significant hazards and requires
specialized knowledge of Modine products
and training in performing those services.
Failure to have any service properly
performed by, or making any modification
to Modine equipment without the use of,
qualified service personnel could result in
serious injury to person and property,
including death. Therefore, only qualified
service personnel should work on any
Modine products.

25-572.10
SPECIAL PRECAUTIONS
SPECIAL PRECAUTIONS
THE INSTALLATION AND MAINTENANCE INSTRUCTIONS
IN THIS MANUAL MUST BE FOLLOWED TO PROVIDE
SAFE, EFFICIENT AND TROUBLE-FREE OPERATION. IN
ADDITION, PARTICULAR CARE MUST BE EXERCISED
REGARDING THE SPECIAL PRECAUTIONS LISTED
BELOW. FAILURE TO PROPERLY ADDRESS THESE
CRITICAL AREAS COULD RESULT IN PROPERTY
DAMAGE OR LOSS, PERSONAL INJURY, OR DEATH.
THESE INSTRUCTIONS ARE SUBJECT TO ANY MORE
RESTRICTIVE LOCAL OR NATIONAL CODES.
HAZARD INTENSITY LEVELS
1. DANGER: Indicates an imminently hazardous situation
which, if not avoided, WILL result in death or serious injury.
2. WARNING: Indicates a potentially hazardous situation
which, if not avoided, COULD result in death or serious injury.
3. CAUTION: Indicates a potentially hazardous situation
which, if not avoided, MAY result in minor or moderate injury.
4. IMPORTANT: Indicates a situation which, if not avoided,
MAY result in a potential safety concern.
IMPORTANT
1. To prevent premature heat exchanger failure, do not
locate ANY gas-fired appliances in areas where corrosive
vapors (i.e. chlorinated, halogenated or acid) are present
in the atmosphere.
2. To prevent premature heat exchanger failure, the input to
the appliance, as indicated on the serial plate, must not
exceed the rated input by more than 5%.
3. To prevent premature heat exchanger failure, observe
heat exchanger tubes by looking at the heat exchanger
through the field installed access openings in connecting
ductwork or the unit access doors where viewing the heat
exchanger is possible. If the bottom of the tubes become
red while blower and duct furnace are in operation, check
to be sure the blower has been set to the proper rpm for
the application. Refer to page 19 for Blower Adjustments.
4. Start-up and adjustment procedures should be performed
by a qualified service agency.
5. To check most of the Possible Remedies in the
troubleshooting guide listed in Table 54.1, refer to the
applicable sections of the manual.
DANGER
Appliances must not be installed where they may be exposed
to a potentially explosive or flammable atmosphere.
WARNING
1. Failure to follow proper lifting instructions and applicable
safety procedures could result in property damage,
serious injury, or death. Lifting should only be done by a
qualified rigging company. Use ALL lifting points. Test
lift to ensure proper balance and rigging. Never lift in
high winds.
2. All field gas piping must be pressure/leak tested prior
to operation. Never use an open flame. Use a soap
solution or equivalent for testing.
3. Gas pressure to appliance controls must never exceed
14" W.C. (1/2 psi).
4. Disconnect power supply before making wiring
connections or working on this equipment. Follow all
applicable safety procedures to prevent accidental
power up. Failure to do so can result in injury or death
from electrical shock or moving parts and may cause
equipment damage.
5. All appliances must be wired strictly in accordance with
wiring diagram furnished with the appliance. Any wiring
different from the wiring diagram could result in a hazard
to persons and property.
6. Any original factory wiring that requires replacement
must be replaced with wiring material having a
temperature rating of at least 105°C.
7. To reduce the opportunity for condensation, the
minimum sea level input to the appliance, as indicated
on the serial plate, must not be less than 5% below the
rated input, or 5% below the minimum rated input of dual
rated units.
8. Ensure that the supply voltage to the appliance, as
indicated on the serial plate, is not 5% greater than the
rated voltage.
(continued next column)
CAUTION
1. Appliances are designed for outdoor installation only.
DO NOT LOCATE APPLIANCES INDOORS.
2. Purging of air from gas lines should be performed as
described in ANSI Z223.1 - latest edition “National Fuel
Gas Code”, or in Canada in CAN/CGA-B149 codes.
3. Ensure that the supply voltage to the appliance, as
indicated on the serial plate, is not 5% less than the rated
voltage.
4. Do not reuse any mechanical or electrical component
which has been wet. Such component must be replaced.
(continued from previous column)
9. When servicing or repairing this equipment, use only
factory-approved service replacement parts. A complete
replacement parts list may be obtained by contacting
Modine Manufacturing Company. Refer to the rating
plate on the appliance for complete appliance model
number, serial number, and company address. Any
substitution of parts or controls not approved by the
factory will be at the owners risk.
WARNING
SI (METRIC) CONVERSION FACTORS
To
Convert Multiply By To Obtain
To
Convert Multiply By To Obtain
“W.C. 0.24 kPa CFH 1.699 m3/min
psig 6.893 kPa Btu/ft30.037 mJ/m3
°F (°F-32) x 0.555 °C pound 0.453 kg
inches 25.4 mm Btu/hr 0.000 kW
feet 0.305 meters gallons 3.785 liters
CFM 0.028 m3/min psig 27.7 “W.C.

35-572.10
Table of Contents
Inspection on Arrival................................................................. 1
Special Precautions.................................................................. 2
SI (Metric) Conversion Factors ................................................ 2
Special Design Requests ......................................................... 4
Storage Prior to Installation...................................................... 4
Unit Location ............................................................................ 4
Combustible Material and Service Clearances ............... 4
Sound and Vibration Levels .................................................... 5
Curb or Sub-Base Mounting..................................................... 5
Slab Mounting ......................................................................... 6
Rigging Instructions.................................................................. 6
Duct Installation/Utility Connections......................................... 7
Venting...................................................................................... 7
Unit Installation......................................................................... 8
Gas Connections .............................................................. 8
Considerations for Elevation........................................... 10
Electrical Connections .....................................................11
Evaporative Cooler ......................................................... 12
Cooling Coil Specifications and Installation.................... 14
Start-Up Procedure ................................................................ 16
Pilot Burner Adjustment................................................. 16
Main Burner Adjustment ................................................ 17
Blower Adjustment......................................................... 19
Lubrication Recommendations ...................................... 19
Damper Linkage Adjustment ......................................... 19
Furnace Control Operating Sequence........................... 20
Variable Air Volume Applications ................................... 21
Cooling Coil Operation .................................................. 21
Component/Option Locations................................................. 22
Component Descriptions ........................................................ 22
General Performance Data .................................................... 32
Pressure Drop Data................................................................ 34
Blower Performance Data. ..................................................... 35
Blower Sheave Assembly Data .............................................. 38
Dimensions............................................................................. 40
Weights................................................................................... 48
Maintenance........................................................................... 50
Service & Troubleshooting ..................................................... 54
Start-Up Checklist .................................................................. 57
Model Designations................................................................ 58
Model Nomenclature .............................................................. 59
Commercial Warranty...............................................Back Cover
TABLE OF CONTENTS

45-572.10
SPECIAL DESIGN REQUESTS / UNIT LOCATION
Location Recommendations
1. When locating the furnace, consider general space and
heating requirements and availability of gas and electrical
supply.
2. Unit must be installed on the positive pressure side of the
circulating blower.
3. Be sure the structural support at the unit location site is
adequate to support the weight of the unit and any other
required support structure. For proper operation the unit
must be installed in a level horizontal position.
4. Do not install units in locations where the flue products
can be drawn into the adjacent building openings such as
windows, fresh air intakes, etc.
5. Be sure that the minimum clearances to combustible
materials and recommended service clearances are
maintained. Be sure clearances are maintained to
the combustion air inlet louvers and power exhauster
discharge cover. Units are designed for installation on
non-combustible surfaces or combustible surfaces with the
minimum clearances shown in Figure 4.1 and Table 4.2.
6. On units that have fresh air openings, a method should be
provided to prevent water and debris from entering the unit
such as a rainhood and bird screen, evaporative cooler,
etc.
7. On horizontal discharge units (Model Digit 2=B or C),
adequate space must be provided to install the discharge
duct as shown in Figure 7.1. to insure even air flow across
the heat exchanger.
CAUTION
Appliances are designed for outdoor installation only.
DO NOT LOCATE APPLIANCES INDOORS.
IMPORTANT
To prevent premature heat exchanger failure, do not locate
ANY gas-fired appliances in areas where corrosive vapors (i.e.
chlorinated, halogenated or acid) are present in the atmosphere.
DANGER
Appliances must not be installed where they may be exposed
to potentially explosive or flammable atmosphere.
Figure 4.1
Combustible Material & Service Clearances j
jMinimum clearance to combustible materials is 1.0" from rooftop.
Table 4.2 - Combustible Material Clearances
UNIT LOCATION
Minimum Combustible Material
Clearances
Recommended
Service Clearances
Model
Size
Access
Side
(A)
Front &
Rear
(B)
Non-
Access
Side
(C)
Access
Side
(A)
Non-
Access
Side
(C)
75 18” 3” 0” 36”
6”
100/125 20” 3” 0” 36”
150/175 25” 3” 0” 42”
200/225 27” 4” 0” 42”
250/300 30” 5” 0” 48”
350/400 41” 11” 0” 60”
500/600 30” 5” 0” 48”
700/800 41” 11” 0” 60”
840/960 41” 11” 0” 60”
SIDE VIEW
B
B
FRONT VIEW
1.00
36.00
C
ACCESS
SIDE
A
Power Exhauster
Discharge Cover
SPECIAL DESIGN REQUESTS
Modine Manufacturing Company will sometimes build units
with special features as requested by the customer. This
manual only covers standard features and does not include any
changes made for special feature requests by the customer.
Units built with special features are noted with a 5-digit SPO
(Special Product Order) Number on the Serial Plate
STORAGE PRIOR TO INSTALLATION
If the unit is stored outside prior to installation, the unit should
be covered.

55-572.10
SOUND ATTENUATION / ROOF CURB INSTALLATION
Sound and Vibration Levels
All mechanical equipment generates some sound and vibration
that may require attenuation. For critical areas, an acoustical
consultant should be retained to assist in the application.
Locating the equipment away from the critical area is desirable
within ducting limitations. Frequently, units can be located
above utility areas, corridors, restrooms, and other non-critical
areas. Generally, a unit should be located within 15 feet of
a primary support beam to minimize structure deflections.
Smaller defections usually results in reduced vibration and
noise transmission.
Install the unit over roof decking with 2" acoustic fiberglass
lining within curb area for sound attenuation. The return air
duct should be acoustically lined and should be installed with
a flexible connection. If the ceiling space is used as a plenum,
the acoustically lined return intake duct should form an inverted
tee with five foot minimum legs in each direction.
The discharge duct should be acoustically insulated and should
have a flexible connection as illustrated.
Figure 5.1 - Suggested Sound Attenuation
Counterflashing
(By Others)
Roofing
Material
(By Others)
Insulation
(By Others)
Cant Strip
(By Others)
2 x 4 Wooden
Nailing Strip*
Curb*
2"Acoustic
Fiberglass
(By Others)
Roof Deck
6" Inverted
Channel
Both Sides
(By Others)
Roof
Truss
Curb Gasketing*
or Caulk by Others
*Available as a factory supplied, field installed accessory.
Roof Insulation
(By Others)
Figure 5.2 - Typical Curb Details
Curb or Sub-Base Mounted Sites
An optional roof curb is available to simplify site preparation
and raise the unit above roof water and snow level for drainage.
It can be installed with the roof, and in advance of the unit.
A sub-base must be furnished by the installer if no curb is
supplied for the roof. The sub-base, either steel or concrete,
must provide required support with the unit bolted to sub-
base. The following are some general guidelines for roof curb
installed units:
1. The roof structure must be adequately designed to
support the live weight load of the unit and any other
required support structure. For the bearing loads normally
encountered, the roof curb should be supported at
points no greater than five feet apart. Additional truss
reinforcement should be provided, if necessary.
2. Roof curb must be installed level. If roof is pitched it will be
necessary to construct a sub-base on which to install the
curb.
3. Roof curbs supplied by Modine are fabricated from 16
gauge galvanized steel and supplied knocked down for
assembly on the job site. The curb consists of two side
pieces, two end pieces, gasketing, four joiner angles, four
2x4 inch wood nailing strips, nuts, bolts, and washers. Roof
curbs over 120 inches long include two additional side
pieces and two splice plates. Refer to the latest revision of
Modine literature 5-590 for instructions.
4. Outside dimensions must be held when installing curb.
Top surface must be level and straight to insure weather-
tightness. All corners must be square.
5. Final electric and gas connections must be made after unit
is installed to allow for tolerance in setting of unit on curb.
For electrical power supply allow approximately eight feet
of wire, plus provisions for weathertight flexible conduit for
connection to unit, as required by local codes.
6. Maintain an 12-inch minimum height from top of roof deck
to top of curb.
7. Caulk butt joints after curb is assembled and installed on
roof structural members and roof flashing is added.

65-572.10
ROOF CURB
INSTALLER’S
EYE BOLTS
INSTALLER’S
CABLES AND
SPREADERS
Figure 6.2 - Typical Rigging
WARNING
Failure to follow proper lifting instructions and applicable
safety procedures could result in property damage, serious
injury, or death. Lifting should only be done by a qualified
rigging company. Use ALL lifting points. Test lift to ensure
proper balance and rigging. Never lift in high winds.
A
B
CONCRETE SLAB
ON GRAVEL BED
(4” MIN)
A & B ARE BETWEEN
ANCHOR POINTS
Figure 6.1 - Slab-Mounted Make-Up Air Unit
Table 6.1 - Slab Anchor Bolt Dimensions
Slab Mounted Units
For Horizontal Discharge (Model Digit 2=B or C)
For ground level installation of a horizontal-discharge unit,
prepare a level concrete slab at least four inches thick on
adequate footings and a generous bed of gravel for drainage
(See Figure 6.1). The slab should include threaded 5/8-inch
anchor bolts spaced as shown in Figure 6.1 and Table 6.1.
Anchor bolts should extend at least 1-1/2" above the surface of
the pad to allow clearance for mounting washers, nuts and bolts
(mounting washers, nuts and bolts by others). The slab should
extend out at least six inches around the perimeter of the unit.
Digit 2 Model Size
Blower Type
(Digit 16) A B
B
75 All 82.91 33.85
100/125 All 82.91 36.36
150/175 All 82.91 40.61
200/225 All 82.91 42.71
250/300 E, F, G, or H 82.91 45.75
I, J, or K 118.50 45.75
350/400 E, F, G, or H 82.91 57.27
I, J, or K 118.50 57.27
500/600 G or H 116.03 45.75
I, J, K, or L 151.62 45.75
700/800 G or H 116.03 57.27
I, J, K, or L 151.62 57.27
840/960 All 185.02 57.27
C
75 All 106.89 33.85
100/125 All 106.89 36.36
150/175 All 106.89 40.61
200/225 All 106.89 42.71
250/300 E, F, G, or H 106.89 45.75
I, J, or K 142.48 45.75
350/400 E, F, G, or H 106.89 57.27
I, J, or K 142.48 57.27
Rigging and lifting of the units should only be done by a
qualified rigging company and follow appropriate industry
standards, including but not limited to the appropriate sections
of ASME B30, OSHA 1910, and OSHA 1926.
Four 3/4-inch holes at the extended ends of the mounting
channels are supplied to facilitate lifting the unit with eyebolts
furnished by the installer. With the lifting points identified, the
units can be lifted by crane or helicopter.
1. Follow site preparation instructions for the roof curb, slab,
or equipment stand before installation.
2. Check the Serial Plate(s) of unit with plans to be sure unit
is properly located. Although units may look outwardly
similar, their function, capacities, options, and accessories
will often vary.
3. Check unit dimensions of both the unit base and the curb
or stand on which the unit will be installed.
4. If the unit will be installed on a roof curb:
a. Thoroughly clean and dry the top of the curb surface.
b. Lay a bead of weather resistant caulking on top
perimeter of roof curb as illustrated in Figure 5.2. Note:
If roof curb is supplied by Modine, full perimeter gasket
material is supplied and caulking is not necessary.
5. When lifting the equipment, connect sturdy steel cables,
chains, or straps with eye loops as illustrated in Figure 6.2.
For stability in lifting and lowering and to prevent damage
to the unit, include a spreader bar as shown in Figure 6.2.
Avoid twisting or uneven lifting of the unit. The cable length
from the lifting point on the unit to the spreader bar should
always be longer than the distance between the outer
lifting points.
6. Test lift the unit to check for proper rigging balance before
hoisting to the desired installation location.
7. Once lifted to the installation location, orient the hoisted
unit to match the ductwork locations and set evenly on the
curb or stand.
8. Following the instructions in this manual, make final unit
connections for ductwork, utilities, and controls.
General Rigging Instructions
SLAB MOUNT INSTALLATION / RIGGING INSTRUCTIONS

75-572.10
DUCT INSTALLATION / UTILITY CONNECTIONS
Utility Connections
Utility and control connections can be made to the unit from
the bottom for roof curb-mounted units or through the fixed
side panels for horizontal supply and return units. Holes can be
made in fixed side panels to accommodate utility connections
as specified according to the unit dimensional drawings.
Sealing of holes cut in the unit casing for utility connections
should be done with care to prevent air and water leaks.
Venting
1. Installation of venting must conform with local building
codes, or in the absence of local codes, with the National
Fuel Gas Code, ANSI Z223.1 (NFPA 54) - Latest Edition.
In Canada, installation must be in accordance with CAN/
CGA-B149.1 for natural gas units and CAN/CGA-B149.2
for propane units.
2. Units are shipped with the power exhauster discharge
cover factory installed.
3. Do not modify or obstruct the combustion air inlet louvers
or the power exhauster discharge cover.
4. Do not add any vents other than those supplied by the
manufacturer.
UNIT BASE
90° FLANGED
DUCTWORK
(BY INSTALLER)
RETURN AIR
CONNECTOR
DISCHARGE AIR
CONNECTOR
ROOF CURB
CAULK ALL MATING SURFACES BEFORE
INSTALLING DUCTWORK TO CONNECTORS
OR SETTING THE UNIT (CAULK BY INSTALLER)
DIMENSION “B” SHOULD NEVER
BE LESS THAN 1/2 OF DIMENSION “A”
PROVIDE LEAK TIGHT ACCESS
PANELS IN DISCHARGE DUCT
FOR HEAT EXCHANGER INSPECTION.
PROVIDE LEAK TIGHT ACCESS
PANELS IN DISCHARGE DUCT
FOR HEAT EXCHANGER INSPECTION.
TURNING
VANES
(3” MAX)
TURNING
VANES
(3” MAX)
TURNING
VANES
(3” MAX)
Figure 7.2 - Recommended Discharge Duct Configs
Duct Installation
1. The blower section inlet and/or return air connections,
as well as the furnace furnace discharge are designed to
accept 90° flanged ductwork as shown in Figure 7.1. To
determine locations and dimensions of connections, refer
to the dimensional drawings later in this manual.
Figure 7.1 - Duct Connections
2. Provide an airtight seal between the ductwork and the unit.
Seams with cracks in the ductwork should be permanently
caulked and/or taped. All duct connections outside the
building MUST be weathertight to prevent rain and snow
from entering the ductwork.
3. Acoustic duct liners are recommended on all internal
supply and return air ducts.
4. Provide uniform air distribution over the heat exchanger.
Use turning vanes in the supply ductwork where required
to obtain uniform air distribution. See Figure 7.2.
Figure 7.3 - Discharge and/or Return Air Connectors
UNIT INLET OR
DISCHARGE
OPENING
90° FLANGED
DUCTWORK ACCESS PANEL FOR
HORIZONTAL DISCHARGE
UNITS (MODEL DIGIT 2=B)
5. On horizontal discharge units with Model Digit 2=B, provide
removable access panels on the downstream side of the
unit as shown in Figure 7.1. These openings should be
large enough to view smoke or reflect light inside the
casing to indicate leaks in the heat exchanger and to check
for hot spots on the heat exchanger due to a lack of
sufficient airflow (CFM). This is not required on horizontal
discharge units with Model Digit 2=C because the cooling
coil cabinet access door can be removed for this purpose.
6. When a roof curb is used in conjunction with a factory
supplied return air connector, the ductwork can be
fastened to the connectors prior to the unit installation.
The connectors will accept 90° flanged ductwork. See
Figure 7.3.
1/2"

85-572.10
WARNING
1. All field gas piping must be pressure/leak tested prior to
operation. Never use an open flame. Use a soap solution or
equivalent for testing.
2. Gas pressure to appliance controls must never exceed
14" W.C. (1/2 psi).
3. To reduce the opportunity for condensation, the minimum
sea level input to the appliance, as indicated on the serial
plate, must not be less than 5% below the rated input, or 5%
below the minimum rated input of dual rated units.
UNIT INSTALLATION
Gas Connections
1. Installation of piping must conform with local building codes,
or in the absence of local codes, with the National Fuel Gas
Code, ANSI Z223.1 (NFPA 54) - Latest Edition. In Canada,
installation must be in accordance with CAN/CGA-B149.1 for
natural gas units and CAN/CGA-B149.2 for propane units.
2. Piping to units should conform with local and national
requirements for type and volume of gas handled, and
pressure drop allowed in the line.
3. Refer to Model Digits 4-6 of the Model Nomenclature on
page 59 and the value on the unit Model ID plate (not
individual furnace serial plates) to determine the gas
heating capacity in Thousands of Btu/hr (MBH). The
Model ID plate is located on the blower section electrical
compartment door. See Figure 8.1 for an example Model
ID plate.
Figure 8.2
Recommended Sediment Trap/Manual Shut-off Valve
Installation - Side or Bottom Gas Connection
GAS
SUPPLY LINE
GAS
SUPPLY LINE
GROUND
JOINT
UNION
W/ BRASS
SEAT
MANUAL GAS
SHUT-OFF VALVE
3"
MIN.
SEDIMENT
TRAP
PLUGGED
1/8" NPT TEST
GAGE CONNECTION
TO
CONTROLS
j
j Manual shut-off valve is in the “OFF” position
when handle is perpendicular to pipe.
CAUTION
Purging of air from gas supply line should be performed as
described in ANSI Z223.1 - latest edition “National Fuel Gas
Code”, or in Canada in CAN/CGA-B149 codes.
IMPORTANT
To prevent premature heat exchanger failure, the input to the
appliance, as indicated on the serial plate, must not exceed
the rated input by more than 5%.
5. The gas piping to the unit can enter the unit from the side
of the unit or from below. Install a ground joint union with
brass seat and a manual shut-off valve external of the unit
casing, and adjacent to the unit for emergency shut-off and
easy servicing of controls, including a 1/8" NPT plugged
tapping accessible for test gauge connection (See Figure
8.2). Verify the manual shut-off valve is gas tight on an
annual basis.
6. Provide a sediment trap before each unit in the line where
low spots cannot be avoided. (See Figure 8.2).
Figure 8.1 - Model ID Plate Example
4. For the length of pipe necessary, determine the pipe
diameter from Tables 9.1 or 9.2 for the unit heating
capacity. Where several units are served by the same
main, the total capacity and length of main must be
considered. While the gas connection(s) on the unit may
be smaller than the required supply pipe diameter, do
not use pipe sizes smaller than what is required leading
up to the unit. At the unit, reduce the pipe size down to
the appropriate size (sizes 75-225 are 1/2" connections,
250-960 are 3/4" connections). Avoid pipe sizes smaller
than 1/2". The inlet pressure to the unit must be 6-7" W.C.
for natural gas and 11-14" W.C. for propane gas. When
sizing the inlet gas pipe diameter, be sure the unit supply
pressure can be met after the line pressure drop has
been subtracted. If the line pressure drop is too high, refer
to NFPA 54 National Fuel Gas Code for other gas pipe
capacities.
7. When Pressure/Leak testing, pressures above 14" W.C.
(1/2 psi), close the field installed shut-off valve, disconnect
the appliance and its combination gas control from the gas
supply line, and plug the supply line before testing. When
testing pressures 14" W.C. (1/2 psi) or below, close the
manual shut-off valve on the appliance before testing.

95-572.10
Table 9.1 - Gas Pipe Capacities - Natural Gas j
Gas pipe capacities based on Table 6.3.1(d) of NFPA 54 for schedule 40
metallic pipe with inlet pressure of 11.0" w.c., with a pressure drop of 0.5" w.c.
and gas specific gravity of 1.50.
INSTALLATION
j Based on natural gas properties of 1050 Btu/ft³ and specific gravity of 0.60.
k Based on propane gas properties of 2500 Btu/ft³ and specific gravity of 1.50.
l Model sizes 500-800 contain 2 furnaces. Values shown are per furnace.
m Model sizes 840-960 contain 3 furnaces. Values shown are per furnace.
Table 9.3 - Burner Orifice Sizing and Gas Consumption
Model
Size
Gas Type Orice
Qty
Natural jPropane k
75 Cfh 72.1 30.0 1
Orice Drill Size 20 39
100 Cfh 96.1 40.0 2
Orice Drill Size 30 45
125 Cfh 120.2 50.0 2
Orice Drill Size 25 42
150 Cfh 144.2 60.0 3
Orice Drill Size 30 45
175 Cfh 168.3 70.0 3
Orice Drill Size 27 43
200 Cfh 192.3 80.0 3
Orice Drill Size 23 42
225 Cfh 216.3 90.0 3
Orice Drill Size 20 39
250 Cfh 240.4 100.0 4
Orice Drill Size 25 42
300 Cfh 288.7 120.0 4
Orice Drill Size 20 39
350 Cfh 336.5 140.0 6
Orice Drill Size 27 43
400 Cfh 384.6 160.0 6
Orice Drill Size 23 42
500
l
Cfh 240.4 100.0 4
Orice Drill Size 25 42
600
l
Cfh 288.7 120.0 4
Orice Drill Size 20 39
700
l
Cfh 336.5 140.0 6
Orice Drill Size 27 43
800
l
Cfh 384.6 160.0 6
Orice Drill Size 23 42
840
m
Cfh 336.5 140.0 6
Orice Drill Size 27 43
960
m
Cfh 384.6 160.0 6
Orice Drill Size 23 42
Pipe
Length (ft)
Capacity in MBH by Nominal Pipe Diameter
1∕2” 3∕4” 1” 1 1∕4” 1 1∕2” 2” 2 1∕2” 3”
10 138 287 540 1,113 1,659 3,203 5,103 9,009
20 95 197 371 762 1,145 2,195 3,507 6,195
30 76 159 298 612 917 1,764 2,814 4,977
40 65 135 255 524 784 1,512 2,405 4,253
50 58 120 226 464 695 1,344 2,132 3,770
60 53 109 205 420 630 1,218 1,932 3,423
70 48 100 188 386 580 1,113 1,775 3,150
80 44 93 175 360 540 1,038 1,659 2,930
90 42 87 165 338 506 974 1,554 2,741
100 40 83 155 319 478 921 1,470 2,594
125 35 74 138 282 423 816 1,302 2,300
150 32 66 125 256 384 739 1,176 2,079
175 29 61 114 235 353 680 1,082 1,911
200 27 57 107 219 329 632 1,008 1,785
250 24 50 95 194 291 561 894 1,575
Pipe
Length (ft)
Capacity in MBH by Nominal Pipe Diameter
1∕2” 3∕4” 1” 1 1∕4” 1 1∕2” 2” 2 1∕2” 3”
10 291 608 1,150 2,350 3,520 6,790 10,800 19,100
20 200 418 787 1,620 2,420 4,660 7,430 13,100
30 160 336 632 1,300 1,940 3,750 5,970 10,600
40 137 287 541 1,110 1,660 3,210 5,110 9,030
50 122 255 480 985 1,480 2,840 4,530 8,000
60 110 231 434 892 1,340 2,570 4,100 7,250
80 101 212 400 821 1,230 2,370 3,770 6,670
100 94 197 372 763 1,140 2,200 3,510 6,210
125 89 185 349 716 1,070 2,070 3,290 5,820
150 84 175 330 677 1,010 1,950 3,110 5,500
175 74 155 292 600 899 1,730 2,760 4,880
200 67 140 265 543 814 1,570 2,500 4,420
250 62 129 243 500 749 1,440 2,300 4,060
Gas pipe capacities based on Table 6.2.1(a) of NFPA 54 for schedule 40
metallic pipe with inlet pressure less than 2 psi, with a pressure drop of 0.3"
w.c. and gas specific gravity of 0.60.
Table 9.2 - Gas Pipe Capacities - Propane Gas k

10 5-572.10
Equation 10.1 - Manifold Pressure for Gas Heating
Values Different Than Shown in Table 10.1
Table 10.3 - High Altitude Kit Contents
Table 10.2 - High Altitude Kit Selection Table jkl
jApplies to both installations in the U.S. and Canada.
kApplies to both natural and propane gas.
l Sizes 75-400 require a kit qty. of 1, sizes 500-800 require a kit qty of 2,
sizes 840-960 require a kit qty of 3.
j Values shown are for 3.5" W.C. manifold pressure for Natural Gas and 10.0"
W.C. for Propane Gas. If the local utility supplies gas with a di󰀨erent Btu/ft³
value, use Equation 10.1 to calculate the required manifold pressure.
k Gas heating values shown are derated 4% per 1,000' of elevation (10%
between 2,000' and 4,500' elevation in Canada) in accordance with ANSI
Z223.1 and CSA-B149, respectively.
l 945 Btu/ft³ for Canada
m 2,250 Btu/ft³ for Canada
n When installed at altitudes above 2,000', a pressure switch may need to be
changed. Refer to Tables 10.2 and 10.3 to determine if a switch change is
required.
Considerations for Elevation
The standard ratings for the duct furnace(s) used in these units
are certified for elevations up to 2000 feet above sea level.
Operation at elevations above 2,000 feet requires ratings be
reduced 4% for each 1000 feet above sea level per ANSI
Z223.1. The exception is for units in Canada, CSA requires that
ratings be reduced 10% for elevations between 2,001 and 4500
feet. The following instructions are for units that will be installed
over 2,000 feet elevation. If this does not apply, you may skip
ahead to the Electrical Connections section on page 11.
Manifold Pressure Adjustment
The unit manifold pressure is factory set for operation at
elevations up to 2000 feet as follows:
• For Natural Gas units, 3.5" W.C. based on a gas heating value
of 1,050 BTU/ft³.
• For Propane Gas units, 10.0" W.C. based on a gas heating
value of 2,500 BTU/ft³.
For higher elevations, some utility companies may derate the
BTU content (heating value) of the gas provided at altitude to a
lower value to allow certain heating appliances to be used with
no manifold pressure adjustments. For this reason it is necessary
that the supplying utility be contacted for detailed information
about the gas type and BTU content (heating value) before
operating any heater. Table 10.1 shows the standard derated
heating values of natural and propane gases at various
elevations.
NOTE: For units equipped with two-stage or modulating gas
controls, only the high fire manifold pressure needs to be
adjusted. No adjustments to the low fire manifold pressure are
necessary on these units.
Selection of the Proper High Altitude Kit
All units installed at elevations greater than 2000 feet above sea
level require a kit, in addition to potential manifold pressure
adjustment outlined in the previous step. To determine the proper
kit to use, refer to Table 10.2.
Table 10.3 shows the contents of the kit. For more information,
refer to the latest revision of Modine Bulletin 75-530.
If the utility is supplying gas with heating values SAME as shown
in Table 10.1, the manifold pressure should remain set to 3.5"
W.C. for natural gas and 10.0" W.C. for propane gas and you
may proceed to the section on this page titled “Selection of the
Proper High Altitude Kit”.
If the utility is supplying gas with heating values DIFFERENT
than shown in Table 10.1, use Equation 10.1 to determine the
appropriate manifold pressure for the elevation and gas heating
value being supplied. Note what that value is, as it will be
needed later for Start-Up. Proceed to the section on this page
titled “Selection of the Proper High Altitude Kit”.
If a unit is to be installed at higher elevations AND converted from
natural gas to propane gas operation, a propane conversion kit
must be used in conjunction with the manifold pressure
adjustment and high altitude kit listed above. For the Selection
and Installation Instructions for propane conversion kits, please
see the latest revision of Modine Bulletin 75-511.
Table 10.1
Gas Heating Values at Altitude (Btu/ft³) jkln
Altitude (ft) Natural Gas Propane
0-2,000 1,050 2,500
2,001-3,000 929 l2,212 m
3,001-4,000 892 l2,123 m
4,001-4,500 874 l2,080 m
4,501-5,000 856 2,038
5,001-6,000 822 1,957
6,001-7,000 789 1,879
7,001-8,000 757 1,803
8,001-9,000 727 1,731
9,001-10,000 698 1,662
Where:
MPELEV = Manifold Pressure (" W.C.) at installed
elevation
BTUTBL = BTU/ft³ content of gas from Table 10.1
BTUACT = BTU/ft³ content of gas obtained from the
utility company
MPSL = Manifold Pressure (" W.C.), at Sea Level
(use 3.5" W.C. for natural gas and
10.0" W.C. for propane)
INSTALLATION
Model Model
Size
Elevation Above Sea Level (ft)
2,001-5,500 5,501-6,500 6,501-7,500
All All Item Code 67248 67248 67248
Item
Code
Kit Contents
High Altitude
Conversion Label
Pressure
Switch
Installation
Instructions
67248 Yes No Ye s

115-572.10
1. Installation of wiring must conform with local building
codes, or in the absence of local codes, with the National
Electric Code ANSI/NFPA 70 - Latest Edition. Unit must
be electrically grounded in conformance to this code. In
Canada, wiring must comply with CSA C22.1, Part 1,
Electrical Code.
2. Two copies of the job specific wiring diagram are provided
with each unit, one located in the duct furnace electrical
junction box and one in the electrical section of the unit
located in the blower compartment. Refer to this diagram
for all wiring connections.
3. External electrical connections to be installed include:
• Supply power (120, 208, 240, 480, or 600 volts).
• Thermostats, remote monitoring panels, building
pressure sensors, time clocks, or any other accessory
control devices that may be supplied (24 volts).
4. All supply power electrical connections are made in the
electrical section of the unit. The low voltage (thermostat
and accessory control devices) may be wired to either the
electrical section or the duct furnace electrical junction
box. Refer to the wiring diagram for the terminal location
of all low voltage wiring.
5. Refer to the unit dimensional drawings in this document
for the location of the drill locator dimples in the side and
bottom of the unit for field drilling the hole for the electrical
conduit entry.
6. Control wiring consists of both 24V analog control wiring
and for models with Model Digit 12=9, low current digital
control signal wiring. To avoid signal interference, the two
types should be run in conduit separate from power wiring.
The analog control wiring should be shielded at one end
of the wiring run. Wiring should be stranded, twisted, and
shielded communication wire.
UNIT INSTALLATION
WARNING
1. Disconnect power supply before making wiring connections
or working on this equipment. Follow all applicable safety
procedures to prevent accidental power up. Failure to do so
can result in injury or death from electrical shock or moving
parts and may cause equipment damage.
2. All appliances must be wired strictly in accordance with
wiring diagram furnished with the appliance. Any wiring
different from the wiring diagram could result in a hazard to
persons and property.
3. Any original factory wiring that requires replacement must
be replaced with wiring material having a temperature rating
of at least 105°C.
4. Ensure that the supply voltage to the appliance, as indicated
on the serial plate, is not 5% greater than rated voltage.
CAUTION
1. Ensure that the supply voltage to the appliance, as indicated
on the serial plate, is not 5% less than the rated voltage.
2. Do not reuse any mechanical or electrical component
which has been wet. Such components must be
replaced.
Electrical Connections 7. The wire gauge must be sized according to the National
Electric Code or CSA code based on amp draw and length
of run. Refer to Table 11.1 for maximum wire lengths that
can be wired between components and the terminal block
on the unit based on the wire gauge being used.
Minimum
Recommended
Wire Gauge
Maximum Distance (feet) from
Control Device to Unit
24V Control Wiring Digital Control Wiring
22 n/a 120
20 n/a 200
18 75 300
16 125 500
14 175 n/a
Table 11.1 - 24V and Digital Control Wire Lengths
Test Probe
Points
Terminal
Numbers
Oval Holes
for Wiring
(two rows each)
Square Holes
for Wire Release
(two rows each)
Figure 11.1 - Terminal Strip Wiring (Model Digit 12=9)
8. FOR UNITS WITH MODEL DIGIT 12=9 (MODINE
CONTROL SYSTEM OPTION): For field wiring to the
factory terminal strip, the terminal strip connections are
designed to clamp down on the wires. To properly connect
the wires to the terminal strip:
• Push a small flat-head screwdriver into the square hole on
the terminal. Press firmly until the screwdriver hits the
back stop and opens the terminal (see Figure 11.1).
• Remove approximately 3/8” of insulation from the end of
the wire and push the stripped wire into the oval hole in
the terminal.
• Remove the screwdriver. Pull on the wire to make sure
that it is securely clamped in the terminal.
• Make sure that the terminal clamp is in contact with bare
wire (insulation removed).
(continued next page)

12 5-572.10
ELECTRICAL CONNECTIONS
Evaporative Cooler Installation
For units equipped with an evaporative cooler (Model Digit
22=D), refer to Installation and Service Manual - Evaporative
Coolers (Literature 5-588).
Figure 12.1 - Recommended Accessory Field
Installed Disconnect Switch Mounting Locations
9. Depending on the configuration of the unit controls,
there may be sensors that are field installed. Review the
unit ordered to verify that the sensors supplied match
the configuration of the unit. The following are sensors
that may be included for field installation (for installation
instructions, refer to the instructions included with the
individual sensors):
• Supply Air Temperature Sensor
This sensor is required on all units and is mounted in the
supply air ductwork downstream of the unit discharge.
• Outdoor Air Sensor
This sensor is required on all units except 100% return air
units. Depending on the unit configuration, the sensor
may be duct mounted or remote mounted.
• Return Air Sensor
This sensor is required on all units that have a mixture of
outside and return air. The sensor is mounted in the
return air ductwork.
• Space Temperature/Humidity Sensor
This sensor is required on all units that have space
temperature/humidity reset control.
• Building Pressure Sensor
This sensor is required on all units that have space
pressure control, either through modulating dampers or
variable frequency drive control on the supply air blower.
• Duct Pressure Sensor
This sensor is required on all units that have duct
pressure control through variable frequency drive control
on the supply air blower.
• Space CO2Sensor
This sensor is required on all units that have demand
based ventilation control based on space CO2
concentration.
• Duct Mounted Smoke Detector
This sensor is mounted in the supply air or return air
ductwork.
For further instructions on the above sensor(s), refer to
the installation instructions that shipped with the
sensor(s).
10. Make sure all multi-voltage components (motors,
transformers, etc.) are wired in accordance with the power
supply voltage.
11. The power supply to the unit must be protected with a
fused or circuit breaker disconnect switch. Refer to the
Factory Mounted Option Locations (Figure 22.1) for the
factory mounted disconnect switch location and then
review the unit to determine if a factory installed dead
front disconnect switch was provided. Accessory field
installed disconnect switches should be mounted where
required by the National Electric Code as shown in Figure
12.1. For fusible disconnect switches, refer to the Model
Identification plate for the fuse size and type.
12. The power supply must be within 5% percent of the voltage
rating and each phase must be balanced within 2 percent
of each other. If not, advise the utility company.
13. All outdoor electrical connections must be weatherized to
prevent moisture from entering the electrical compartment.
Figure 12.2 - Evaporative Cooler (Model Digit 22=D)

135-572.10
THIS PAGE INTENTIONALLY LEFT BLANK
UNIT INSTALLATION

14 5-572.10
UNIT INSTALLATION
Figure 14.1 - Cooling Section (DX Coil Shown)
Optional double
wall construction
DX single circuit (shown) and
dual circuit coils available
Optional Factory
Installed
DX or Chilled
Water coil.
Fin spacings
of 6,8,10,12
or 14 fins per inch
Adjustable
mounting bracket
for 2,3,4 and 6 row
coils
Full coverage
3-way sloping
409 stainless
steel drain pan
1” stubbed drain
connection
Right or left hand coil
header access to match
gas controls
Condensate Drain Pan Trap
The condensate drain line needs to include a P-trap
immediately downstream of the connection to the unit. This
trap should extend at least two inches below the connection
to prevent air pressure from forcing air into the unit. The
trap should be primed with a water/glycol solution to prevent
freezing.
1. Inspect the refrigerant distributor and verify that the nozzle
is in place.
2. All field brazing welding should be performed using high
quality materials and an inert gas purge (such as nitrogen)
to reduce oxidation of the internal surface of the coil.
3. The use of filter-dryers in the system piping is
recommended along with a sight glass that has a moisture
indicator.
4. Connect the suction line and suction connection.
5. Install the expansion valve (by others). Follow the
expansion valve manufacturer's recommendations for
installation to avoid damaging the valve.
6. Connect the liquid line to the expansion valve. Pressurize
the coil, expansion valve assembly and suction connection
to 100 psig with dry nitrogen or other suitable gas. The coil
should be left pressurized for a minimum of 10 minutes.
7. If the coil holds pressure, the installation can be considered
leak free. If the pressure drops by 5 psi or less,
repressurize the coil and wait another 10 minutes. If the
pressure drops again, there are more than likely one or
more small leaks, which should be located and repaired.
Pressure losses greater than 5 psi would indicate a larger
leak, which should be isolated and repaired. Be sure to
check valves and fittings as potential sites for leakage or
bleed.
8. Use a vacuum pump to evacuate the coil and any
interconnecting piping that has been open to atmosphere.
Measure the vacuum in the piping using a micron gauge
located as far from the pump as possible (the vacuum
at the pump will be greater than the rest of the system).
Evacuate the coil to 500 microns or less then close the
valve between the pump and the system. If the vacuum
holds to 500 microns or less for one minute, the system
SUCTION LINE
EXPANSION
VALVE
(BY OTHERS)
REMOTE
SENSING BULB
STRAPS SUCTION CONNECTION
COIL
SUCTION HEADER
DISTRIBUTOR
EQUALIZER LINE
NOZZLE
LIQUID LINE
Figure 14.2 - General DX Piping
Direct Expansion (DX) Piping
The refrigerant lines should be insulated to prevent warming
or cooling of the refrigerant. If the suction line is allowed to
be cooled, liquid will condense in the line and can severely
damage the compressor. If the liquid line is warmed, the
refrigerant can "flash" into a gas. This will cause erratic
operation of the expansion device and impair the heat transfer
ability of the cooling coil. Long runs of piping need to be
periodically supported to prevent excess vibration that can
damage the piping and joints. It is recommended to provide
dampening supports at intervals of length equivalent to 15 tube
diameters.
Cooling Coil Units
Units with a cooling section (Model Digit 2=C or P) can be
provided with a factory installed direct expansion (DX) coil, a
chilled water (water or water/glycol mixtures) coil, or the coil
can be field supplied and installed by others. For units equipped
with a factory installed cooling coil (Model Digit 23=1), refer to
the packing slip to determine the coil type provided.
The section includes a full coverage, 3-way sloping stainless
steel drain pan to remove condensate from coil headers and
piping components. Insulation is standard on outdoor units
and optional on indoor units. The cabinet includes two doors,
a removable upper door for service access to the coil once the
plumbing has been installed and a lower door which includes
a 1" drain connection to the exterior of the cabinet. Field
connections for coil inlet and outlet piping can be made through
the cabinet corner post or back of the unit. The cooling section
duct transition includes 1-1/2" flanges for fastening the sides
of the coil. The bottom duct transition is angled to remove any
condensation that may be entrained in the supply air stream.
For field supplied coils, do not exceed the maximum coil
dimensions listed in Literature 82-135. If the coil supplied is
smaller than the listed dimensions, field supplied blank off
plates are required to prevent air bypass around the coil. The
coil is supported by two 14 gauge support rails which contain
mounting provisions for fastening 4", 5", 6", 7.5", 8.5", and 10"
deep coils.

155-572.10
UNIT INSTALLATION
is ready to be charged or refrigerant pumped down in
another portion of the system can be opened to the coil. A
steady rise in microns would indicate that moisture is still
present and that the coil should be further vacuumed until
the moisture has been removed.
9. Failure to obtain a high vacuum is indicative of a great
deal of moisture or a small leak. Break the vacuum with a
charge of dry nitrogen or other suitable gas and recheck
for leaks (soapy water works well). If no leaks are found,
continue vacuuming the coil until the desired vacuum is
reached.
10. All field piping must be self-supporting.
Chilled Fluid Piping
To prevent noise and coil damage from water hammer, an
air vent is necessary to bleed off the accumulated air in the
system. The vent should be located on the top of the inlet
manifold where the air collects. This vent should be opened
twice a year.
The outlet manifold should have a drain installed on the
bottom to allow for periodic flushing of the system to remove
sediments and corrosion products from the cooling coil. This
drain should be opened to allow some fluid to drain twice
a year. Check coloration and viscosity of the effluent for
indications of corrosion in the system. The lines between the
unit and the structure should be insulated to prevent freezing of
the water.
1. Once installed, the coil should be pressurized to 100 psig
with dry nitrogen or other suitable gas. The coil should be
left pressurized for a minimum of 10 minutes. If the coil
holds the pressure, the hook-up can be considered leak
free. If the pressure drops by 5 psig or less re-pressurize
the coil and wait another 10 minutes. If the pressure drops
again, there is more than likely one or more small leaks
which should be located and repaired. Pressure losses
greater than 5 psig would indicate a larger leak that should
be isolated and repaired.
2. All field brazing and welding should be performed using
high quality materials and an inert gas purge (such as
nitrogen) to reduce oxidation of the internal surface of the
coil.
3. All field piping must be self supporting. System piping
should be flexible enough to allow for thermal expansion
and contraction of the coil.
4. Fill the coil with water with all air vents open so that air
is eliminated from within the coil circuitry and headers.
Verify that all vents and drains are not obstructed and do
discharge a stream of water.
5. Close all vents and perform a hydrostatic leak test
of all brazed , threaded or flanged joints, valves and
interconnecting piping. Recheck the coil level and correct
if necessary. When the setup is found to be leak free,
discharge and discard initial water charge. It is important
that all grease, oil, flux and sealing compounds present
from the installation be removed.
Air Vent
Gate Valve
Tee
Vent Plug
Return
Air Flow
Supply
Dirt Leg
Cap
Union
Drain Plug
Figure 15.1 - General Chilled Fluid Piping
Table 15.1 - Cooling Coil Performance Limits
j Based on 550 feet per minute (FPM) coil face velocity.
k Based on 95°F/75°F Entering Dry Bulb/Wet Bulb.
l Model Size 75 minimum CFM for DX Dual Circuit is 621.
m Model Size 100 minimum CFM for DX Dual Circuit is 745.
Cooling
Type
Model
Size
Min
CFM
Single Circuit Dual Circuit Max
Cooling
(Tons) k
Max
CFM j
Area
(ft²)
Max
CFM j
Area
(ft²)
DX
75 688 l1,891 3.44 1,707 3.10 9.4
100 802 m
2,206 4.01 2,048 3.72 11.4
125 926
150 1,111 2,521 4.58 2,416 4.39 13.4
175 1,296
200 1,481 3,352 6.09 3,165 5.76 18.1
225 1,667
250 1,852 3,724 6.77 3,538 6.43 20.2
300 2,222
350 2,593 5,214 9.48 4,996 9.08 27.3
400 2,963
Chilled
Water
75 609 1,676 3.05 n/a n/a 10.6
100 741 2,011 3.66 n/a n/a 12.6
125 926
150 1,111 2,372 4.31 n/a n/a 14.8
175 1,296
200 1,481 3,214 5.84 n/a n/a 19.3
225 1,667
250 1,852 3,592 6.53 n/a n/a 21.3
300 2,222
350 2,593 5,073 9.22 n/a n/a 29.3
400 2,963

16 5-572.10
START-UP PROCEDURE
Refer to page 58 for the Start-up Checklist.
1. Turn off power to the unit at the disconnect switch. Check
that fuses or circuit breakers are in place and sized
correctly. Turn all hand gas valves to the “OFF” position.
2. Remove the blower exterior panels and open the electrical
compartment door.
3. Check that the supply voltage matches the unit supply
voltage listed on the Model Identification plate. Verify that
all wiring is secure and properly protected. Trace circuits to
insure that the unit has been wired according to the wiring
diagram.
4. Check to insure that the venting system is installed and
free from obstructions.
5. Check to see that there are no obstructions to the intake
and discharge of the unit.
6. Check the belt tension and sheave alignment. Refer to
Blower Adjustments for proper belt tension.
7. Check bearings for proper lubrication. For units provided
with pillow block bearings (See Model Nomenclature),
refer to Lubrication Recommendations for requirements.
8. Check to make sure that all filters are in place and that
they are installed properly according to direction of air flow.
9. Perform a visual inspection of the unit to make sure no
damage has occurred during installation.
10. Turn on power to the unit at the disconnect switch. Check
to insure that the voltage between duct furnace electrical
box terminals 1 and 2 is 24V.
11. Check the thermostat, ignition control, gas valve, and
supply fan blower motor for electrical operation. If these do
not function, recheck the wiring diagram. Check to insure
that none of the Control Options have tripped.
12. For units with a return air damper, the return air damper
linkage needs to be adjusted. Refer to Damper Linkage
Adjustment.
13. Check to make sure that the damper opens properly
without binding.
14. Check the blower wheel for proper direction of rotation
when compared to the air flow direction arrow on the
blower housing. Blower wheel rotation, not air movement,
must be checked as some air will be delivered through the
duct furnace with the blower wheel running backwards.
15. Check the blower speed (rpm). Refer to Blower
Adjustments for modification.
16. Check the motor speed (rpm).
17. Check the motor voltage. On three phase systems, check
to make sure all legs are in balance.
18. Check the motor amp draw to make sure it does not
IMPORTANT
1. To prevent premature heat exchanger failure, observe
heat exchanger tubes by looking at the heat exchanger
through the field installed access openings in connecting
ductwork or the unit access doors where viewing the heat
exchanger is possible. If the bottom of the tubes become
red while blower and duct furnace are in operation, check
to be sure the blower has been set to the proper rpm for
the application. Refer to page 16 for Blower Adjustments.
2. Start-up and adjustment procedures should be performed
by a qualified service agency.
exceed the motor nameplate rating. On three phase
systems, check all legs to insure system is balanced.
19. Recheck the gas supply pressure at the field installed
manual shut-off valve. The minimum inlet pressure should
be 6" W.C. on natural gas and 11" W.C. on propane gas.
The maximum inlet pressure for either gas is 14" W.C. If
inlet pressure exceeds 14" W.C., a gas pressure regulator
must be added upstream of the combination gas valve.
20. Open the field installed manual gas shut-off valve.
21. Open the manual main gas valve on the combination
gas valve. Call for heat with the thermostat and allow the
pilot to light for intermittent pilot ignition. If the pilot does
not light, purge the pilot line. If air purging is required,
disconnect the pilot line at outlet of pilot valve. In no case
should the line be purged into heat exchanger. Check the
pilot flame length (See Pilot Flame Adjustment).
22. Once the pilot has been established, check to make sure
that the main gas valve opens. Check the manifold gas
pressure (See Main Gas Adjustment) and flame length
(See Air Shutter Adjustment) while the supply fan blower is
operating.
23. Check to insure that gas controls sequence properly (See
Control Operating Sequence). Verify if the unit has any
additional control devices and set according to the
instructions in the Control Options.
24. Once proper operation of the unit has been verified,
remove any jumper wires that were required for testing.
25. Close the electrical compartment door.
26. Replace all exterior panels.
Pilot Burner Adjustment
The pilot burner is orificed to burn properly with an inlet
pressure of 6-7" W.C. on natural gas and 11-14" W.C. on
propane gas. Final adjustment must be made after installation.
If the pilot flame is too long or large, it may cause soot and/
or impinge on the heat exchanger causing failure. If the pilot
flame is too short, it may cause poor ignition or result in the
controls not opening the combination gas control. A short flame
can be caused by a dirty pilot orifice. The pilot flame should be
observed periodically to assure trouble-free operation.
To Adjust the Pilot Flame
1. Create a call for heat from the thermostat.
2. Remove the cap from the pilot adjustment screw. For
location, see the combination gas control literature supplied
with unit.
3. Adjust the pilot length by turning the screw in or out
to achieve a soft steady flame 3/4" to 1" long and
encompassing 3/8"-1/2" of the tip of the flame sensing rod
(See Figure 16.1).
4. Replace the cap from the pilot adjustment screw.
3/4" to 1"
Start-Up Procedure
Figure 16.1 - Correct Pilot Flame
Flame Sensing Rod

175-572.10
Figure 17.1 - Checking Gas Pressure with Manometer
MANIFOLD
TEE
START-UP PROCEDURE
Main Burner Adjustment
The gas pressure regulator (integral to the combination gas
control) is adjusted at the factory for average gas conditions.
It is important that gas be supplied to the duct furnace in
accordance with the input rating on the serial plate. Actual
input should be checked and necessary adjustments made
after the duct furnace is installed. Over-firing, a result of too
high an input, reduces the life of the appliance and increases
maintenance. Under no circumstances should the input exceed
that shown on the serial plate.
Check/Adjust Pressure at the Combination Gas Valve
This section applies to all units, regardless of gas control type.
1. Turn the field installed manual shut-off valve to “OFF”.
2. Remove the 1/8" pipe plug in the pipe tee or gas valve and
attach a U-tube type water manometer which is at least 12"
high and capable of reading to 0.1" W.C. See Figure 17.1.
3. Turn the field installed manual gas shut-off valve to “ON”.
1
10
9
8
7
6
23
4
5
Figure 17.2 - Maxitrol Modulating Valve Adjustments
1. TOP HOUSING
2. COVER PLATE
3. SEAL GASKET
4. MAX ADJUSTMENT SCREW
5. MAX ADJUSTMENT SPRING
6. SOLENOID
7. MIN ADJUSTMENT SPRING
8. PLUNGER
9. MIN ADJUSTMENT SCREW
10. MIN ADJUSTMENT SCREW STOP
4. Create a high fire call for heat from the thermostat.
5. Determine the correct high fire manifold pressure, which
depends on gas type and gas control type. Review the
furnace Model Digit 11 and 12 (not the system model
number) and adjust the main gas pressure regulator spring
to achieve the proper manifold pressure as shown in Table
17.1. For location of regulator adjustment, refer to the
combination gas control literature supplied with the unit.
7. After adjustment, move the field installed manual shut-off
valve to the “OFF” position, remove the manometer, and
replace the 1/8" pipe plug.
8. After the plug is in place, move the field installed manual
shut-off valve to the “ON” position and recheck pipe plugs
for gas leaks with soap solution.
9. Proceed to the section "Air Shutter Adjustment".
Check/Adjust Pressure for the Modulating Valve
This section only applies to units with Electronic Modulation gas
controls (Model Identification Digit 12=4, 7, 8, or 9). Refer to
the appropriate instructions for the valve type on the unit.
For Units with Model Digit 12=4, 7, or 8:
The low fire gas pressure needs to be adjusted. This needs to
be repeated on each furnace in multiple furnace units. Using
Figure 17.2 for item locations, this is accomplished as follows:
1. Disconnect power.
2. Remove all wires from Maxitrol Amplifier terminal “3” or
duct furnace terminal “43” (if available).
3. Turn on power at the disconnect switch.
4. Remove the cover plate (2), maximum adjustment screw
(4), spring (5), and plunger (8). A small magnet is useful for
this purpose. CAUTION - The plunger is a precision part.
Handle carefully to avoid marring or picking up grease and
dirt. Do not lubricate.
5. Using minimum adjusting screw (9), adjust low fire manifold
pressure to 0.56" W.C. for natural gas and 1.6" W.C. for
propane gas.
6. Replace plunger and spring retainer, spring, and maximum
adjusting screw in proper order.
7. Using maximum adjustment screw (4), adjust high fire
manifold pressure to 3.5" W.C. for natural gas and 10"
W.C. for propane gas.
8. Disconnect power.
9. Replace cover plate (2) and re-install all wires from Maxitrol
amplifier terminal “3” or duct furnace terminal “43”.
10. After adjustment, move the field installed manual shut-off
valve to the “OFF” position, remove the manometer, and
replace the 1/8" pipe plug.
(continued next page)
U-TUBE
MANOMETER
Furnace
Model Digit 11
Furnace
Model Digit 12 Manifold Pressure
N
(Natural)
1, 2, 4, 7, 8 3.5”
9 j4.0”
P
(Propane)
1, 2, 4, 7, 8 10.0”
9 j10.5”
6. If the unit has Electronic Modulation gas controls (Model
Identification Digit 12=4, 7, 8, or 9), skip steps 7 through
9 in this section and proceed to the next section "Check/
Adjust Pressure for the Modulating Valve", otherwise
continue to the next step.
Table 17.1 - Manifold Gas Pressure - Main Valve
jFor units with Model Digit 12=9 and multiple furnaces, only one furnace
will be Model Digit 12=9, the additional furnaces will be Model Digit 12=2,
therefore pressures will be different for those furnaces.

18 5-572.10
START-UP PROCEDURE
11. After the plug is in place, move the field installed manual
shut-off valve to the “ON” position and recheck p ipe plugs
for gas leaks with soap solution.
12. Proceed to the section "Air Shutter Adjustment".
For Units with Model Digit 12=9:
The high fire gas pressure needs to be adjusted first, followed
by the low gas pressure. For multiple furnace units, this is only
required on the duct furnace that has the modulating valve
(Model Digit 12=9). This is accomplished as follows:
1. Verify the main valve (valve before the modulating valve)
outlet pressure has been set to 4.0” W.C. for natural gas
or 10.5" W.C. for propane gas per instructions and table
17.1 on the previous page. For multiple furnace units,
the furnaces without the modulating valves are to remain
at 3.5" W.C. for natural gas or 10.0" W.C. for propane
gas. For location of regulator adjustment, refer to the
combination gas control literature supplied with the unit.
2. The Maxitrol EXA modulating valve series has a cover
secured with two screws that must be removed. Once
removed, there are a bank of (3) DIP switches and two
buttons and a communication LED for the user interface as
shown in Figure 18.1.
3. Verify that the DIP switches are properly set to the "OFF"
position for switches 1 and 3 and "ON" for switch 2.
4. Adjust the High Fire Setting as follows:
a. Enable the unit controls and create a call for heat.
b. Press and hold Button #1 on the modulating valve until
the LED lights solid red, then release.
c. With the valve now in the high fire setting mode,
confirm or adjust the high fire manifold pressure to be
3.5" W.C. If the pressure needs to be adjusted, press
or hold Button #1 to increase gas flow and press or
hold Button #2 to decrease gas flow.
d. If 3.5" W.C. cannot be attained, recheck the inlet gas
pressure as described previously. After addressing
any issues, if 3.5" W.C. still cannot be attained, step
the valve closed using button #2 to the point where
manifold pressure begins to be impacted. If the
pressure at that point is less than 3.3" W.C., recheck
your inlet pressure with the unit operating and adjust
as required.
e. Save the setting by simultaneously holding Buttons
#1 and #2 until the LED turns OFF. If this is not
performed within 5 minutes, the control will default
to the previously saved settings and return to normal
operating mode.
4. Adjust the Low Fire Setting as follows:
a. Press and hold Button #2 on the modulating valve until
the LED light blinks red, then release.
b. With the valve now in the low fire setting mode,
confirm or adjust the low fire manifold pressure to be
no less than the minimum shown on the furnace serial
plate in the box called “Min. Manifold Pressure”. If the
pressure needs to be adjusted:
c. Press or hold Button #1 to increase gas flow and #2
to decrease gas flow. It is best to push and release
button #2 to single step the valve to the minimum
manifold pressure. Holding the button is likely to cause
Air Shutter Adjustment
Proper operation provides a soft blue flame with a well-defined
inner core. A lack of primary air will reveal soft yellow-tipped
flames. Excess primary air produces short, well-defined flames
with a tendency to lift off the burner ports. For both natural
and propane gas, the air shutters can be adjusted to control
the burner flame height. The air shutters can be accessed by
reaching behind the manifold tee in Figure 17.1. The larger
models may require the removal of the manifold (see Manifold
Assembly Removal).
Adjusting the primary combustion air is achieved by resetting
the primary air shutters (See Figure 54.2). Prior to flame
adjustment, operate duct furnace for about fifteen minutes. The
main burner flame can be viewed after loosening and pushing
aside the gas designation disc on the side of the burner box.
1. To increase primary air, loosen the air shutter set screws and
move the air shutters closer to the manifold until the yellow
tipped flames disappear and a clean blue flame with a well
defined inner cone appears.
2. To decrease primary air, move the air shutters away from the
manifolds until flames no longer lift from burner ports, but
being careful not to cause yellow tipping.
3. Re-tighten set screws after adjustment.
ON
123
1234
BUTTON #1
BUTTON #2
CONTROL SIGNAL TERMINALS
SUPPLY POWER TERMINALS
POSITION FEEDBACK
WIRING TERMINALS
DIP SWITCHES
(1=“OFF”, 2=“ON”, 3=“OFF”)
LED INDICATOR
Figure 18.1 - Maxitrol EXA Modulating Valve
the valve to close too far and lose flame.
d. Save the setting by simultaneously holding Buttons
#1 and #2 until the LED turns OFF. If this is not
performed within 5 minutes, the control will default
to the previously saved settings and return to normal
operating mode.
5. Once the setting of the modulating valve has been
completed, replace the valve cover removed earlier.
6. Move the field installed manual shut-off valve to the “OFF”
position, remove the manometer, and replace the 1/8" pipe
plug.
7. After the plug is in place, move the field installed manual
shut-off valve to the “ON” position and recheck the pipe
plug for gas leaks with soap solution.
8. Proceed to the section "Air Shutter Adjustment".
Check/Adjust Pressure for the Modulating Valve
(continued)

195-572.10
START-UP PROCEDURE
Blower Adjustments
All belt drive supply fan speed adjustments can be made with
the adjustable sheave on the blower motor as follows:
1. Refer to page 38 to determine correct blower speed
according to job requirements, then proceed to the next
step.
2. Turn off power to the unit at the disconnect switch. If
equipped with gas heat option, turn all hand gas valves to
the “OFF” position.
3. Loosen the belt tension and remove the belt.
4. On the motor sheave, loosen the set screw on the side
away from the motor (see Figure 19.1).
MOTOR
SHAFT
SET SCREW
ADJUSTABLE HALF
OF SHEAVE
Figure 19.1 - Motor Sheave Adjustment
3/4" DEFLECTION
WITH 5 LBS. OF FORCE
Figure 19.2 - Belt Tension Adjustment
9. Retighten motor base. Motor base should be shifted for
proper belt tension which is 3/4" deflection with about 5 lbs.
of force. Refer to Figure 19.2.
10. Turn on power to the unit and initiate blower motor
operation. Do not fire gas controls until blower adjustment
has been made or unit may cycle on high limit control.
5. Turn outer side of motor sheave clockwise until motor
sheave is fully closed.
6. From fully closed position, turn outer side of motor sheave
counterclockwise until the proper number of turns open
are achieved. Turns should be done in half-turns (180°
rotations). Each half turn results in a change of blower
speed and air volume of approximately 2.5-5%. Adjusting
the half of the sheave inward increases blower speed,
adusting outward decreases blower speed.
7. Tighten the set screw on the flat portion of the motor shaft.
8. Replace the belt and verify that the belts are aligned in the
sheave grooves properly and are not angled from sheave
to sheave.
Figure 19.3 - Damper Linkage Adjustment
DAMPER
BLADE
BALL JOINT CONNECTING ROD
BLADE ARM
11. Check the motor amps to ensure the maximum motor amp
rating is not exceeded. Verify airflow volume and repeat
steps above for further adjustment.
12. If equipped with gas heat, turn on the gas and initiate
burner operation.
13. Verify the temperature rise and supply air temperature of
the heating section do not fall outside the range or exceed
the maximums shown in Table 32.1.
14. After 24 hours of operation, retighten the setscrews to the
torque listed in the owners manual on the bearing, sheave,
and blower wheel to avoid damage to the unit.
Lubrication Recommendations
The blower can be provided with either spider or pillow block
bearings. Spider bearings are permanently lubricated and
do not require lubrication. Pillow block bearings are shipped
greased from the factory but will require lubrication. The
bearings should be checked and lubricated before each heating
season but a more frequent lubrication schedule may be
required based on the environment in which the unit is installed,
and the frequency of the equipment operation. Shell Alvania #2
lubricant is recommended.
Damper Linkage Adjustment
If the unit is provided with a return air damper, to prevent
shipping damage, the return air damper linkage is disconnected
and the damper closed. Before operating the unit, the fresh and
return air dampers must be connected. This is accomplished by
the following:
1. The damper actuator should be de-energized and the fresh
air damper in a fully closed position.
2. Open the return air damper in a fully open position.
3. Slide the connecting rod into the ball joint on the blade arm
with the return air damper fully open. See Figure 19.3.
4. Tighten the 5/16" hex head screw on the ball joint.

20 5-572.10
START-UP PROCEDURE
Furnaces are supplied with intermittent pilot systems with
continuous retry, which both the main burner and pilot burner
are turned off 100% when the thermostat is satisfied.
Control Options (see page 23) could change the listed
sequence of operation for the unit based on their function. The
descriptions given below are for the basic duct furnace.
Single Furnace Controls
Single furnace units (Model Digits 4-6=75 through 400) are
offered with different types of gas control:
• Staged Control (Model Digit 12=1 or 2): These furnaces
utilize a single- or two-stage combination gas valve, an
ignition control, and a low voltage thermostat.
• Electronic Modulating Control (Model Digit 12=4, 7, or
8): These furnaces utilize a single-stage combination gas
valve, an electronic modulating gas valve, a modulating
amplifier, an ignition control, and one of the following:
» Modulating room thermostat
» Modulating duct thermostat with remote temperature
set point adjuster
» Building Management System (BMS) signal by others
(an inverted signal where 0VDC or 4mA is high fire
and 10VDC or 20mA is low fire).
• Electronic Modulating Control with Modine Control
System (Model Digit 12=9): These furnaces utilize
a single-stage combination gas valve, an electronic
modulating gas valve, a programmable microprocessor
based controller, an ignition control, and different sensors
depending on the application, but most commonly include:
» A duct temperature sensor
» A space temperature sensor
» There is also BMS integration capability for BACnet or
LonWorks protocol systems.
The control operating sequence for all furnaces is as follows:
1. The thermostat calls for heat or is enabled by the BMS.
2. The power exhauster relay is energized starting the
power exhauster motor. Once the motor has reached full
speed, the differential pressure switch closes. The power
exhauster pre-purge time delay relay then closes after 20
to 40 seconds and energizes the gas control circuit.
3. The pilot valve opens and the spark igniter sparks in an
attempt to light the pilot. The system will attempt to light
the pilot for 70 seconds. If the pilot is not sensed for any
reason, the ignition control will wait for approximately
six minutes with the combination gas control closed and
no spark. After six minutes, the cycle will begin again.
After three cycles, some ignition controllers lockout for
approximately one hour before the cycle begins again. This
will continue indefinitely until the pilot flame is sensed or
power is interrupted to the system.
IMPORTANT
To prevent premature heat exchanger failure, with all control
systems, a blower starting mechanism must be provided so
that the blower is running or energized within 45 seconds of
the gas control operation.
Furnace Control Operating Sequence 4. Once the pilot is lit, the flame sensor proves the pilot and
stops the spark igniter from sparking.
5. The main gas valve is opened and the main burner is
controlled as follows:
a. Single-Stage Furnaces (Model Digit 12=1): The main
burner is lit to 100% full fire.
b. Two-Stage Furnaces (Model Digit 12=2): The main
burner is lit to 50% fire. If the temperature at the
thermostat continues to fall, the thermostat will call for
high stage heat and the main burner is lit to 100% full
fire.
c. Modulating Room or Duct Thermostat (Model
Digit 12=4): The main gas valve is opened 100%
and the burner firing rate is modulated between 40%
and 100% full fire. A resistance signal (8000 to 12000
ohms) in the thermostat is converted by the modulating
amplifier to an inverted DC voltage (between 0VDC
for high fire to 12 VDC for low fire) and applied to the
modulating gas valve to control the gas flow to the
main burner.
Note: When modulating duct sensing is utilized, a
room override thermostat can be added. When the
room override calls for heat, the burner modulates to
full fire operation until the room override is satisfied.
The unit then reverts back to duct sensing control.
When equipped with both, either the duct sensor or
the room override thermostat can call for heat.
d. BMS Signal (Model Digit 12=7 or 8): The main gas
valve is opened 100% and the burner firing rate is
modulated between 40% and 100% full fire. A BMS
0-10VDC or 4-20mA signal (inverted, such that 0 VDC
or 4 mA is high fire and 10 VDC or 20 mA is low fire)
is converted by the signal conditioner/modulating
amplifier into an inverted DC voltage (between 0VDC
for high fire to 12 VDC for low fire) and applied to the
modulating gas valve to control the gas flow to the
main burner. The signal conditioner can accept a 0-10
VDC signal when all the dip switches are in the “OFF”
position and 4-20 mA signal when all the dip switches
are in the “ON” position.
Note: For further information regarding the operation
of any of the electronic modulating system options
above, consult the literature provided with the unit.
e. Modulating with Modine Control System (Model
Digit 12=9): The main gas valve is opened 100% and
the burner firing rate is modulated between 40% and
100% full fire. Heating demand is determined by the
Modine Control System through a comparison of the
supply air or space temperature to setpoint and a DC
voltage (between 2VDC for low fire to 10 VDC for high
fire) is applied to the modulating gas valve to control
the gas flow to the main burner.
Note: Typically the temperature control is via supply
air with the space sensor used to reset the supply air
temperature setpoint. For additional information, refer
to the Modine Control System Manual, literature #74-
510 that shipped with the unit.
6. If the unit was provided with a time delay relay, the blower
starts after 30 to 45 seconds.
7. Once the temperature is satisfied, both the main and pilot
valves close 100%. Blower operation may or may not
continue, depending on application.