Modine Manufacturing GAS-FIRED HEATERS PD, GAS-FIRED HEATERS BD User Manual

6-553.3

5H73889A (Rev. D)

April, 2002

NSTALLATION AND SERVICE MANUAL

I

gas-fired unit heaters

models PD and BD

All models approved for use in California by the CEC (when
equipped with IPI), in New York by the MEA division, and in
Massachusetts. Unit heater is certified for non-residential
applications.

WARNING

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
throroughly before installing or servicing this
equipment.

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.

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.

Contents

Inspection on arrival ................................................................1

Installation (including venting)..............................................2-8

Operation ...........................................................................9-10

Checking input rate ...............................................................11

Dimensional data .............................................................12-13

Performance data.............................................................12-19

Service instructions – safety devices..............................20-21

Service instructions – general...............................................22

Troubleshooting................................................................22-24

Motor data........................................................................25-26

Model identification ...............................................................26

Control options ......................................................................27

Warranty ..................................................................Back cover

Pages

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.

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.

Inspection on Arrival

1. Inspect unit upon arrival. In case of damage, report
immediately to transportation company and your local
Modine 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 received for conformance with description of
product ordered (including specifications where applicable).

THIS MANUAL IS THE PROPERTY OF THE OWNER.

PLEASE BE SURE TO LEAVE IT WITH THE OWNER WHEN YOU LEAVE THE JOB.

Heater Parts from ACF Greenhouses

INSTALLATION

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.

1. Disconnect power supply before making wiring connections to
prevent electrical shock and equipment damage. All units must be
wired strictly in accordance with wiring diagram furnished with the
unit.

2. Turn off all gas before installing unit heaters.

3. Gas pressure to unit heater controls must never exceed 14” W.C.
(1/2 psi).

When leak testing the gas supply piping system, the unit and its
combination gas control must be isolated during any pressure
testing in excess of 14" W.C. (1/2 psi).

The unit should be isolated from the gas supply piping system by
closing its field installed manual shut-off valve during any pressure
testing of the gas supply piping system.

4. Check gas inlet pressure at unit upstream from the combination gas
control. The inlet pressure should be 6”-7” W.C. on natural gas or
12”-14” W.C. on propane gas. Purging of gas piping should be
performed as described in ANSI Z223.1 Latest Edition, or in
Canada in CAN/CGA-B149 codes.

5. All units must be vented to the outside atmosphere.

6. Do not install in potentially explosive or flammable atmospheres
laden with grain dust, sawdust, or similar air-borne materials. In
such applications a blower type heater installed in a separate room
with ducting, including appropriate back flow prevention dampers, to
the dust-laden room is recommended.

7. Installation of units in high humidity or salt water atmospheres will
cause accelerated corrosion resulting in a reduction of the normal
life span of the units.

8. To prevent premature heat exchanger failure do not locate ANY gas­fired unit in areas where chlorinated, halogenated or acid vapors
are present in the atmosphere.

9. Avoid installing units in extremely drafty locations. Drafts can cause
burner flames to impinge on heat exchangers which shortens life.
Maintain separation between units so discharge from one unit will
not be directed into the inlet of another.

10. Do not locate units in tightly sealed rooms or small compartments
without provision for adequate combustion air and venting.
Combustion air must have access to the confined space through a
minimum of two permanent openings in the enclosure, at least one
near the bottom. They should provide a free area of one square inch
per 1000 BTU per hour input rating of the unit with a minimum of
100 square inches for each opening, whichever is greater.

11. Do not install unit outdoors.

12. For all sizes, minimum clearance to combustibles from the bottom is
12" and from the sides 18"; for PD sizes 30-50 from the top is 1"
and from the flue collar 2"; for PD sizes 75-300 from the top is 2"
and from the flue collar is 3"; for PD 350 from the top is 3" and from
the flue collar is 4"; for PD 400 from the top is 4" and from the flue
collar is 5"; and for all BD sizes from the top and flue collar is 6".

13. Allow at least 6” clearance at the sides and 12” clearance at rear (or
6” beyond end of motor at rear of unit, whichever is greater) to
provide ample air for combustion and proper operation of fan.

14. The minimum distance from combustible materials based on the
combustible material surface not exceeding 160°F. Clearance from
the top of the unit may be required to be greater than 6” if heat
damage, other than fire, may occur to materials above the unit
heater at the temperature described.

15. Do not install units below 7 feet measured from the bottom of the
unit to the floor.

16. Modine unit heaters are designed for use in heating applications
with ambient temperatures between 32° F and 90° F If an
application exists where ambient temperatures can be expected to
fall outside of this range, contact factory for recommendations.

17. Provide clearance for opening hinged bottom for servicing. See
Figure 1. Do not set unit on its bottom.

18. To assure that flames do not impinge on heat exchanger surfaces,
the unit must be suspended in a vertical and level position. Failure
to suspend unit properly may shorten the life of the unit heater.

19. Do not lift unit heater by gas controls, gas manifold, or power
exhauster.

20.

Be sure no obstructions block air intake and discharge of unit heater.

21. Do not attach duct work, air filters, or polytubes to any propeller
(PD) model unit heaters.

22. In aircraft hangars, keep the bottom of the unit at least 10’ from the
highest surface of the wings or engine enclosure of the highest
aircraft housed in the hangar and in accordance with the
requirements of the enforcing authority and/or NFPA No. 409 –
Latest Edition .

23. In garages or other sections of aircraft hangars such as offices and
shops which communicate with areas used for servicing or storage,
keep the bottom of the unit at least 7’ above the floor. In public
garages, the unit must be installed in accordance with the Standard
for Parking Structures NFPA #88A and the Standard for Repair
Garages NFPA #88B. In Canada, installation of unit heaters in
airplane hangars must be in accordance with the requirements of
the enforcing authority, and in public garages in accordance with the
current CAN/CGA-B149 codes.

24. Consult piping, electrical, and venting instructions in this manual
before final installation.

25. All literature shipped with your unit should be kept for future use for
servicing or service diagnosis. Do not discard any literature shipped
with your unit.

26. Gas-fired heating equipment which has been improperly vented, or
which experiences a blocked vent condition may have the flue
gases accidentally spilled into the heating space. See page 20 for
specific information about the blocked vent safety switch supplied on
the unit.

27.

When servicing or repairing this equipment, use only Modine
approved service replacement parts. A complete replacement parts
list may be obtained by contacting Modine Manufacturing Company.
Refer to the rating plate on the unit for complete unit model number,
serial number and company address. Any substitution of parts or
controls not approved by Modine will be at owners risk.

Figure 1
Hinged Bottom for Burner Service

*(See Dimension "C", page 12)

WING SCREWS

THAT SECURE

HINGED

BOTTOM

THIS IS

DIMENSION C,

SEE PAGE 12

2

Heater Parts from ACF Greenhouses

INSTALLATION

In the U.S., the installation of these units must comply with the
“National Fuel Gas Code,” ANSI Z223.1, latest edition (also known
as NFPA 54) and other applicable local building codes.

In Canada, the installation of these units must comply with local
plumbing or waste water codes and other applicable codes and
with the current code CAN/CGA-B149.1, “Installation Code for
Natural Gas Burning Appliances and Equipment” or CAN/CGA­B149.2, “Installation Code for Propane Burning Appliances and
Equipment.”

1. All installation and service of these units must be performed by
a qualified installation and service agency only as defined in
ANSI Z223.1, latest edition or in Canada by a licensed gas fitter.

2. This unit is certified by C.S.A., with the controls furnished. For
replacement parts, submit the complete model and serial
numbers shown on rating plate on the unit. Modine reserves the
right to substitute other authorized controls as replacements.

3. Unit is balanced for correct performance. Do not alter fan or
operate motors at reduced speed.

4. Information on controls is supplied separately.

5. Modine unit heaters use the same burner for natural and
propane gases.

L

ocating Unit Heaters

CAUTION

Units must not be installed in potentially explosive,
flammable, or corrosive atmosphere.

To prevent premature heat exchanger failure do not locate
ANY gas-fired unit in areas where chlorinated, halogenated
or acid vapors are present in the atmosphere.

In locating units, consider general space-heating requirements,
availability of gas, and proximity to vent locations. Unit heaters
should be located so heated air streams wipe exposed walls
without blowing directly against them. In multiple unit installations,
arrange units so that each supports the air stream from another,
setting up circulatory air movement in the area, but maintain
separation between units so discharge from one unit will not be
directed into the inlet of another. In buildings exposed to prevailing
winds, a large portion of the heated air should be directed along the
windward wall. Avoid interference of air streams as much as
possible.

Mounting height (measured from bottom of unit) at which unit
heaters are installed is critical. Maximum mounting heights are
listed in Table 7 on page 18. Alternate mounting heights for units
with deflector hoods or nozzles are shown on pages 14,16 and 17.
The maximum mounting height for any unit is that height above
which the unit will not deliver heated air to the floor.The maximum
mounting heights must not be exceeded in order to assure
maximum comfort.

Modine unit heaters are designed for use in heating applications
with ambient temperatures between 32° F and 90° F. If an
application exists where ambient temperatures can be expected to
fall outside of this range, contact factory for recommendations.

C

ombustion Air Requirements

Units installed in tightly sealed buildings or confined spaces should
be provided with two permanent openings, one near the top of the
enclosure and one near the bottom. Each opening should have a
free area of not less than one square inch per 1,000 BTU per hour
of the total input rating of all units in the enclosure, freely
communicating with interior areas having, in turn, adequate
infiltration from the outside.

U

nit Suspension

The most common method of hanging Modine gas unit heaters is
to utilize 3/8" threaded rod. On each piece of threaded rod used,
screw a nut a distance of about one inch onto the end of the
threaded rods that will be screwed into the unit heater. Then put a
washer over the end of the threaded rod and screw the threaded
rod into the unit heater weld nuts on the top of the heater at least 5
turns, and no more than 10 turns. Tighten the nut you first installed
onto the threaded rod to prevent it from turning. Drill holes into a
steel channel or angle iron at the same centerline dimensions as
the heater that is being installed. The steel channels or angle iron
pieces need to span and be fastened to appropriate structural
members. Cut the threaded rods to the preferred length, push
them through the holes in the steel channel or angle iron and
secure with washers and lock nuts or lock washers and nuts. A
double nut arrangement can be used here instead of at the unit
heater (a double nut can be used both places but is not necessary).
The entire means of suspension must of course be adequate to
support the weight of the unit (see page 14 and 15 for unit weights).

For proper operation, the unit must be installed in a level horizontal
position. Clearances to combustibles as specified above must be
strictly maintained. Do not install standard unit heaters above the
maximum mounting height shown in Table 7 on page 13, or below
seven feet from the bottom of the unit to the floor.

CAUTION

For all sizes, minimum clearance to combustibles from the
bottom is 12" and from the sides 18"; for PD sizes 30-50 from
the top is 1" and from the flue collar 2"; for PD sizes 75-300
from the top is 2" and from the flue collar is 3"; for PD 350
from the top is 3" and from the flue collar is 4"; for PD 400
from the top is 4" and from the flue collar is 5"; and for all BD
sizes from the top and flue collar is 6".
Allow at least 12" at the rear or 6" beyond the end of the
motor (whichever is greater), to provide ample air for
combustion and for proper operation of fan. Provide clearance
for opening at the hinged bottom for servicing - See Figure 1.

On all propeller units, except the PD 350 and PD 400, two tapped
holes (3/8-16) are located in the top of the unit to receive threaded
rods.

Units with two point suspension, models PD30 through PD300,
incorporate a level hanging feature. Depending on what options and
accessories are being used, the heater may not hang level as
received from the factory. Do not hang heaters with deflector hoods
until referring to the “installation manual for deflector hoods” and
making the recommended preliminary adjustments on the heater.
These preliminary adjustments need to be made with the heater
resting on the floor.

PD30 through PD300 units without deflector hoods that do not
hang level after being installed, can be corrected in place. Simply
remove both outer side panels (screws to remove are on back
flange of side panel) and you will see the (adjustable) mounting
brackets (Fig. 2). Loosen the set screws holding the mounting
brackets in place and using a rubber mallet or something similar,
tap the heater into a position where it does hang level. Re-tighten
set screws and replace the outer side panels.

3

Heater Parts from ACF Greenhouses

INSTALLATION

The PD 350 and PD 400 have four mounting holes. On all
blower units, except the PD 350 and PD 400, two tapped holes
are provided in the top of the unit and two holes in the blower
support bracket. The PD 350 and PD 400 have four tapped
holes in the top of the unit and two in the blower support

T

bracket for mounting.

o assure that flames are directed into
the center of heat exchanger tubes, unit must be supported in a
vertical position, with suspension hangers “UP.” Check with a
level. This is important to the operation and life of unit.

NOTE

: Pipe hanger adapter kits, are available as accessories from
Modine. The hardware allows for pipe caps to be secured into the top of
the unit heater with machine screws (machine screws are 3/8 - 16 x

1.75 UNC-2A THD). The pipe caps can then accommodate 3/4" NPT
pipe for mounting.
N

OTE:Avent
from the unit or the flue collar to the outside atmosphere. A
the pipe which connects the unit to a vent or chimney.

is the vertical passageway used to convey flue gases

flue collar

Figure 2
Adjustable Mounting Brackets - To Adjust:

1. Remove outer side panels.

2. “Set screws” - loosen and
position bracket where needed
– then tighten set screws.

3. Re-attach outer side panels.

CAUTION

Gas Unit Heaters must be vented – do not operate
unvented. A built-in draft hood (diverter) is provided –
additional external draft hoods (diverters) are not required
or permitted. Gas-fired heating equipment that has been
improperly vented or which experiences a blocked vent
condition may have flue gases accidentally spilled into the
heated space. See page 20 for specific information about
the blocked vent safety switch supplied on the unit.

Installation must conform with local building codes or in the
absence of local codes, with Part 7, Venting of Equipment,
of 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.

Venting Instructions

1. All units with single-stage controls are Category I.

2. All units with two-stage or modulating controls are Category
II. The installation of a Category II unit must conform to the
requirements from Table 1 in addition to those listed below.

3. Select size of vent pipe to fit vent pipe connection at rear of
appliance (see Page 12 and 13, Dimension J). Do not use a
vent pipe smaller than the vent pipe connection on the unit.
Vent pipe should be galvanized steel or other suitable
corrosion-resistant material. Follow the National Fuel Gas
Code for minimum thicknesses of vent material; minimum
thicknesses for flue collars vary depending on pipe
diameter.

4. Limit length of horizontal runs to 75% of vertical height.
Install with a minimum upward slope from unit of 1/4 inch
per foot and suspend securely from overhead structure at
points no greater than 3 feet apart. For best venting, put as
much vertical vent as close to the unit as possible. Fasten
individual lengths of vent together with at least three
corrosion-resistant sheet-metal screws.

4

5. Avoid venting through unheated space when possible. When
venting does pass through an unheated space, Modine
recommends the use of Type B double wall vent. If single
wall vent is used, insulate vent runs greater than 5 feet to
minimize condensation. Use insulation that is
noncombustible with a rating of not less than 350°F. Install a
tee fitting at the low point of the vent system to provide a
drip leg with a clean out cap as shown in Figure 3. The drip
leg should be cleaned annually.

6. Keep single wall vent pipe at least 6 inches from
combustible material. For double wall vent pipe, maintain
clearances listed on vent pipe (Category I and II units) (see
page 2, section 12 for allowable reductions). The minimum
distance from combustible material is based on the
combustible material surface not exceeding 160°F.

is

Clearance from the vent connector, vent, or top of unit may
be required to be greater than the minimum clearance if
heat damage other than fire (such as material distortion or
discoloration) may occur.

7. Where the vent passes through a combustible floor or roof,
a metal thimble 4 inches greater than the vent diameter is
necessary. If there is 6 feet or more of vent pipe in the open
space between the unit and where the vent pipe passes
through the floor or roof, the thimble need only be 2 inches
greater than the diameter of the vent pipe. If a thimble is not
used, all combustible material must be cut away to provide
the specified clearance to combustibles. Any material used
to close the opening must be noncombustible.

Table 1
ANSI Unit Heater Venting Requirements

Category Description Venting

I

II

III

I

V

Negative vent pressure Follow standard
Non-condensing venting requirements.

Negative vent pressure Condensate must be
Condensing drained.

Positive vent pressure Vent must be gastight.
Non-condensing

Positive vent pressure Vent must be liquid and
Condensing gastight. Condensate

8. Top of vertical vent should extend at least two feet above
the highest point where it passes through a roof and at least
2 feet higher than any portion of a building within a
horizontal distance of 10 feet (see Figure 3).

9. Use a vent terminal to reduce downdrafts and moisture in
vent. A vent terminal that is very open will avoid spillage at
unit’s diverter relief opening and tripping of the blocked vent
safety switch.

10.Check vent system to see that combustion products are
being vented properly. Operate unit for several minutes and
then pass a lighted match around the edge of the diverter
relief opening. If the flame is drawn into the opening, the
vent system is drawing properly. If not, make adjustments to
provide adequate draft (see page 21).

11.A drip leg with cleanout cap is recomended for all vent
systems to reduce the opportunity of damage to unit due to
condensation.

ADDITIONAL VENTING REQUIREMENTS FOR CATEGORY II
UNITS

Vent system must provide for drainage of condensate. At the
low point of the vent system, install a tee fitting with a
connector and attach flexible tubing, minimum 3/8 inch I.D., and
run to a drain. Tee fitting and associated condensate disposal
system must be periodically cleaned.

Requirements

must be drained.

Heater Parts from ACF Greenhouses

INSTALLATION

ADDITIONAL VENTING REQUIREMENTS FOR VENTING
INTO AN EXISTING MASONRY CHIMNEY OR COMMON
VENT (CATEGORY I and II UNITS ONLY)

1. Do not vent a Category I or II unit into a common vent with
mechanical draft systems operating under positive pressure
(Category III or IV units).

2. When connecting vent to an existing chimney, do not push
vent pipe beyond internal surface of chimney.

3. When venting into a common vent, the area of the common
vent should be equal to or greater than the area of the
largest vent plus 50 percent of the area of all additional
vents.

4. When venting into a common vent, the individual vents
should enter at different levels.

Figure 3
Unit Heater Venting

10' MIN.

TO WALL OR ADJOINING BUILDING

APPROVED

TERMINAL

2'

*

MIN.

ROOF FLASHING

USE THIMBLE

THROUGH CEILING

1/4"

DRIP LEG WITH
CLEANOUT CAP

P

iping

UNIT

1'0"

SLOPE 1/4" TO

THE FOOT

*SIZE ACCORDING TO EXPECTED SNOW DEPTH.

CAUTION

Gas pressure to unit heater controls must never exceed 14"
W.C. (1/2 psi).

When leak testing the gas supply piping system, the
appliance and its combination gas control must be isolated
during any pressure testing in excess of 14" W.C. (1/2 psi).
The appliance should be isolated from the gas supply piping
system by closing its field installed manual shut-off valve
during any pressure testing of the gas supply piping system.

1. Installation of piping must be in accordance with local

codes, and ANSI Z223.1, “National Fuel Gas Code,” or
CAN/CGA-B149 in Canada.

2. Piping to units should conform with local and national

requirements for type and volume and gas handled, and
pressure drop allowed in the line. Refer to Table 4, to
determine the cubic feet per hour (cfh) for the type of gas
and size of unit to be installed. Using this cfh value and the
length of pipe necessary, determine the pipe diameter from
Table 3. Where several units are served by the same main,
the total capacity, cfh, and length of main must be
considered. Avoid pipe sizes smaller than 1/2”. Table 3
allows for the usual number of fittings with a 0.3” W.C.
pressure drop. Where the gas supplied has a specific
gravity other than 0.60, apply the multiplying factor as given
in Table 2.

D

o not use flexible connectors

3. After threading and reaming the ends, inspect piping and
remove loose dirt and chips.

4. Support piping so that no strains are imposed on unit or
controls.

5. Use two wrenches when connecting piping to unit controls.

6. Provide a sediment trap before each unit and in the line
where low spots cannot be avoided. (See Figure 4).

7. Take-off to unit should come from top or side of main to
avoid trapping condensate.

8. Piping, subject to wide temperature variations, should be
insulated.

9. Pitch piping up toward unit at least 1/4” per 15’ of horizontal
run.

10. Compounds used on threaded joints of gas piping must be
resistant to action of liquefied petroleum gases.

11. Purge air before lighting unit by disconnecting pilot tubing

I

at combination gas control.

n no case should line be

purged into heat exchanger.

12. After installation, check system for gas leaks, using a soap
solution.

13. Install a ground joint union and a manual shut off valve
immediately upstream of the unit including a 1/8” NPT
plugged tapping accessible for test gage connection. (See
Figure 4).

14. Allow at least 5 feet of piping between any pressure
regulator and unit control string.

15. 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.

Table 2
Specific Gravity Conversion Factors

Multiplying factors to be used with Table 3 cubic ft./hr. values when the specific
gravity of gas is other than 0.60.

N

ATURAL GAS
Specific
Gravity Factor

0.55 1.04

0.60 1.00

0.65 0.962

PROPANE GAS
Specific
Gravity Factor

1.50 0.633

1.53 0.626

1.60 0.612

Figure 4
Recommended Piping to Controls

GAS

SUPPLY LINE

GROUND

JOINT

VALVE

UNION

PLUGGED

1/8" NPT TEST

GAGE CONNECTION

CONTROLS

TRAP

MANUAL

SHUT-OFF

.

GAS

SUPPLY LINE

3"

MIN.

SEDIMENT

TO

5

Heater Parts from ACF Greenhouses

INSTALLATION

Table 3
Gas Pipe Capacities

In Cu. Ft. per Hour with Pressure Drop pf 0.3 in. W.C. with Specific Gravity 0.60.

Length of

Pipe in Ft.

15

0

3
45
60
75

90
105
120
150
180
210
240
270
300
450
600

1/2 3/4 1 1 1/4 1 1/2 2 3 4 6 8

76 218 440 750 1220 2480 6500 13880 38700 79000
73 152 285 590 890 1650 4700 9700 27370 55850
44 124 260 435 700 1475 3900 7900 23350 45600
50 105 190 400 610 1150 3250 6800 19330 39500

97 200 345 545 1120 3000 6000 17310 35300
88 160 320 490 930 2600 5400 15800 32250
80 168 285 450 920 2450 5100 14620 29850

158 270 420 860 2300 4800 13680 27920
120 242 380 710 2000 4100 12240 25000
128 225 350 720 1950 4000 11160 22800

Diameter of Pipe - Inches

205 320 660 1780 3700 10330 21100
190 300 620 1680 3490 9600 19740
178 285 580 1580 3250 9000 18610
170 270 545 1490 3000 8500 17660
140 226 450 1230 2500 7000 14420
119 192 380 1030 2130 6000 12480

Wiring

CAUTION

Disconnect power supply before making wiring connections
to prevent electrical shock and equipment damage. ALL
UNITS MUST BE WIRED STRICTLY IN ACCORDANCE
WITH WIRING DIAGRAM FURNISHED WITH UNIT.

ANY WIRING DIFFERENT FROM WIRING DIAGRAM MAY
BE HAZARDOUS TO PERSONS AND PROPERTY.

Any damage to or failure of Modine units caused by incorrect
wiring of the units is not covered by MODINE’S STANDARD
WARRANTY (see Back Cover).

All field installed wiring must be done in accordance with the
National Electrical Code ANSI/NFPA 70 – Latest Edition or
Canadian Electrical Code CSA C22.1 Part 1 or local codes.
Unit must be electrically grounded according to these codes.
See wiring diagram shipped with unit.

The power to these unit heaters should be protected with a
circuit breaker. Units for use with single-phase electric power,
should be provided with a manual motor starter, having
properly sized overload protection. Units for use with three­phase electric power must be provided with a motor starter
having properly sized overload protection.

Location of thermostat should be determined by heating
requirements and be mounted on an inside wall about 5' above
floor level where it will not be affected by heat from the unit or
other sources, or drafts from frequently opened doors. See
instructions packed with thermostat.

I

nstallation of Blower Models (BD UNITS)

CAUTION

Proper air flow and distribution, across the heat exchanger
must be provided to prevent early failure of the blower unit
heater.

Attachment of Field Installed Ductwork, Blower
(BD) Models Only

Burned-out heat exchanger as well as shorter equipment life
will result from not providing uniform air distribution.

When installing heater always follow good duct design practices

CAUTION

Do not attempt to attach ductwork of any kind to propeller PD
models.

for even distribution of the air across the heat exchanger.
Recommended layouts are shown below. When installing
blower units with ductwork the following must be done.

rovide uniform air distribution over the heat exchanger.

P

1.
Use turning vanes where required. See figures below.

2. Provide removable access panels in the ductwork on the
downstream side of the unit heater. 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 exchanger due to poor air distribution or
lack of sufficient air.

3.

If ductwork is connected to the rear of the unit use Modine
blower enclosure kit or if using field designed enclosure
maintain dimensions of blower enclosure as shown on page 13.

CAUTION

Check for red heat exchanger tubes. If bottom of tubes
become red while blower unit is in operation, check for
proper air volume and air distribution. Adjust blower speed or
correct discharge duct design to correct problem.

6

Heater Parts from ACF Greenhouses

INSTALLATION

Recommended Installations

TURNING

VANES
3" MIN.

3" MAX.

B

A

B

12" MIN.

SIDE VIEW

A

BAFFLE

SIDE VIEW SIDE VIEW TOP VIEW

3" MAX.

B

TURNING

VANES

TURNING

VANES

BAFFLE

BAFFLE

SIDE VIEW

12"

MIN.

B

A

BA

3" MIN.

12"

A

12"

MIN.

Dimension “B” Should Never
Be Less than 1/2 of “A”

C

12"

B

MIN.

A

TOP VIEW

FED

12"

MIN.

TURNING

VANES

Installation of Blower Models (BD UNITS)

Determining Blower Speed

The drive assembly and motor on all gas-fired blower unit
heaters are factory assembled. The adjustable motor sheave
has been pre-set to permit operation of this unit under average
conditions of air flow and without any external static pressure.
The motor sheave should be adjusted as required when the
unit is to be operated at other than average air flows and/or
with external static pressures. Adjustment must always be
within the performance range shown on pages 18 and 19 and
the temperature rise range shown on the unit’s rating plate.

To determine the proper blower speed and motor sheave turns
open, the conditions under which the unit is to operate must be
known. If the blower unit is to be used without duct work,
nozzles or filters, the only criteria for determining the motor
sheave turns open and blower speed is the amount of air to be
delivered. The performance tables for blower models are shown
on pages 18 and 19. As an example, a model BD 350 unit,
operating with no external static pressure, that is, no duct work,
nozzles, etc., and is to deliver an air volume of 6481 cfm (cfm =
cubic feet of air per minute) requires that the unit be supplied
with a 5 hp motor, a C207 drive, and the drive sheave must be
set at 2.5 turns open to achieve a blower speed of 960 rpm
(see performance table for units with or without blower
enclosure, page 18). See "Blower Adjustments" on page 8 for
setting of drive pulley turns open.

If a blower unit is to be used with ductwork or nozzles, etc., the
total external static pressure under which the unit is to operate,
and the required air flow must be known before the unit can be
properly adjusted. Any device added externally to the unit, and
which the air must pass through, causes a resistance to air
flow. This resistance is called pressure loss. The total of the
pressure losses must be determined before adjusting the
blower speed.

If Modine filters are used, the expected pressure loss through
the filters is included in the performance data on page 19. If
Modine supplied discharge nozzles are used, the expected

pressure drop of the nozzles can be found footnoted at the
bottom of page 14. If filters, nozzles or ductwork are to be used
with the unit, and they are not supplied by Modine, the design
engineer or installing contractor must determine the pressure
loss for the externally added devices or ductwork to arrive at
the total external static pressure under which the unit is to
operate.

Once the total static pressure and the required air flow are
known, the operating speed of the blower can be determined
and the correct motor sheave adjustments made. As an
example, let's say, a model BD 350 is to be used with a Modine
supplied blower enclosure and Modine supplied filters attached
to someone else's ductwork. The unit is to move 6481 cfm or
air flow against an external static pressure of 0.2" W.C. Also,

0.2" W.C. must be added for the filter pressure drop for a total
of 0.4" W.C. total pressure drop. Entering the performance table
on page 18 for a BD 350, at 6481 cfm and 0.4" W.C. static
pressure, it is seen that the unit will require a 5 hp motor using
a C207 drive, and the motor sheave should be set at .5 turns
open to achieve a blower speed of 1050 rpm. You can see this
example differs from similar conditions in paragraph 2 by the
number of turns open and a higher rpm, which is needed to
overcome the added external static pressure from the filters.

7

Heater Parts from ACF Greenhouses

INSTALLATION

To Install (Figure 5)

1. Remove and discard the motor tie down strap and the
shipping block beneath the belt tension adjusting screw
(Not used on all models.)

Figure 5
Blower Model

THREADED ROD MOUNTING

BRACKETS ON BLOWER ASSEMBLY

MOTOR

MOUNTING

BRACKET

BLOWER
SHEAVE

MOTOR

ADJUSTMENT

BLOWER

HOUSING

MOTOR SHEAVE

2. Adjust motor adjusting screw for a belt deflection of
approximately 3/4" with five pounds of force applied midway
between the sheaves (refer to Figure 6a). Since the belt
tension will decrease dramatically after an initial run-in
period, it is necessary to periodically re-check the tension.
Excessive tension will cause bearing wear and noise.

3. The blower bearings are lubricated for life; however, before
initial unit operation the blower shaft should be lubricated at
the bearings with SAE 20 oil. This will reduce initial friction
and start the plastic lubricant flowing.

4. Make electrical connections according to the wiring
diagram.

5. Check rotation of the blower. Motor should be in clockwise
rotation when facing motor pulley. If rotation is incorrect,
correction should be made by interchanging wiring within
the motor. See wiring diagram on the motor.

6. The actual current draw of the motor should be determined.
Under no condition should the current draw exceed that
shown on the motor rating plate.

7. It is the installers responsibility to adjust the motor sheave
to provide the specified blower performance as listed on
pages 18 & 19 for blower settings different from the factory
set performance. The drive number on the unit may be
identified by referring to the Power Code number on the
serial plate of the unit (see page 26 for model number
nomenclature) and matching that number with those shown
on page 25. From the listing, the drive number can be
determined.

8. Blower sheave and motor sheave should be measured to
assure correct drive is on unit. Refer to page 26 for drive
sizes.

SCREW

adjustable motor sheave is supplied with these units. If blower
fan speed changes are required, adjust motor sheave as
follows:

N

OTE: Do not fire unit until blower adjustment has been made

or unit may cycle on limit (overheat) control.

Shut-off power before making blower speed adjustments.

1.
Refer to Determining Blower Speed on page 7 and to
Performance Date on pages 18 and 19 to determine
proper blower RPM.

2. Loosen belt and take belt off of motor sheave.

3. Loosen set screw on outer side of adjustable motor sheave
(see Figure 6).

4. To reduce the speed of the blower, turn outer side of motor
sheave counterclockwise.

5. To increase the speed of the blower, turn outer side of
motor sheave clockwise.

6. Retighten motor sheave set screw, replace belt and
retighten motor base. Adjust motor adjusting screw such
that there is 3/4” belt deflection when pressed with 5
pounds of force midway between the blower and motor
sheaves (see Figure 6a). Since the belt tension will
decrease dramatically after an initial run-in period, it is
necessary to periodically re-check the tension to assure
continual proper belt adjustment.

7. Check to make certain motor sheave and blower sheave
are aligned. Re-align if necessary.

8. Re-check blower speed after adjustment.

9. Check motor amps. Do not exceed amps shown on motor
nameplate. Slow blower if necessary.

10. Check air temperature rise across unit. Check temperature
rise against values shown in Performance Tables on
pages18 and19 to assure actual desired air flow is being
achieved.

11. If adjustments are required, recheck motor amps after final
blower speed adjustment.

Figure 6
Motor Sheave Adjustment

TOWARD MOTOR

SET SCREW

ADJUSTABLE HALF

OF SHEAVE

Figure 6a
Belt Tension Adjustment

B

lower Adjustments

Following electrical connections, check blower rotation to
assure blow-through heating. If necessary interchange wiring to
reverse blower rotation. Start fan motor and check blower
sheave RPM with a hand-held or strobe-type tachometer. RPM
should check out with the speeds listed in Performance Data
shown on pages 18 and 19. A single-speed motor with an

8

3/4" DEFLECTION

WITH 5# FORCE

Heater Parts from ACF Greenhouses

OPERATION

CAUTION

Start-up and adjustment procedures should be performed by
a qualified serviceman.

Check the gas inlet pressure at the unit upstream of the
combination gas control. The inlet pressure should be 6"-7"
W.C. on natural gas or 12"-14" W.C. on propane. If inlet
pressure is too high, install an additional pressure regulator
upstream of the combination gas control.

The pilot flame must be adjusted as described below. Purging
of air from gas lines, piping, and lighting the pilot should be
performed as described in ANSI Z223.1-latest edition
“National Fuel Gas Code” (CAN/CGA-B149 in Canada).

Be sure no obstructions block air intake and discharge of unit
heater.

Prior to Operation

Although this unit has been assembled and fire-tested at the
factory, the following pre-operational procedures should be
performed to assure proper on-site operation:

1. Turn off all electric power to the unit.

2. Check burner to insure proper alignment.

3. Check fan clearance. Fan should not contact casing when
spun by hand.

4. Check all electrical connections to be sure they are secure.

5. If you are not familiar with the unit’s controls (i.e.
combination gas control), refer to the control manufacturer’s
literature supplied with the unit.

6. Check that all horizontal deflector blades are open a
minimum of 30° as measured from vertical.

L

ighting Instructions (also on unit)

For Units with Standing Pilot

1. Set thermostat to lowest setting. Move gas control knob (or
lever) to off and wait 5 minutes.

2. Move gas control knob to PILOT (or move gas control lever
to SET) and depress reset button while lighting the pilot and
hold for 1 minute after pilot is lit.

3. Move gas control knob (or lever) to ON.

4. Set thermostat to desired setting.

F

or Units with Intermittent Pilot

1. Set thermostat to lowest setting. Move gas control knob (or
lever) to off and wait 5 minutes.

2. Move gas control knob (or lever) to ON.

3. Set thermostat to desired setting (pilot and main burner will
light automatically when thermostat calls for heat).

S

hut Down Instructions

Turn off power and close manual gas valve.

A

fter Initial Start Up

1. Check pilot flame adjustment as discussed below.

2. Check gas piping for leaks with a soap bubble solution to

insure safe operation.

3. Check gas input rate to assure proper gas flow and

pressure.

Figure 7
Correct Pilot Flame

ilot Flame Adjustment

P

The pilot burner is orificed to burn properly with an inlet
pressure of 6-7" W.C. on natural gas and 12-14" W.C. on
propane gas, but final adjustment must be made after
installation. Adjust to have a soft steady flame 3/4" to 1" long
and encompassing 3/8"-1/2" of the tip of the thermocouple or
flame sensing rod. Normally this flame will produce satisfactory
results. To adjust flame use pilot adjustment screw on
combination gas control (for location, see the combination gas
control literature supplied with unit). If the pilot flame is longer
and larger than shown by Figure 7, it is possible that it may
cause soot and/or impinge on the heat exchanger causing
burnout. If the pilot flame is shorter than shown it may cause
poor ignition and result in the controls not opening the
combination gas control. A short flame can be caused by a
dirty pilot orifice. Pilot flame condition should be observed
periodically to assure trouble-free operation.

Figure 8
Typical combination gas control

GAS CONTROL KNOB

PRESSURE REGULATOR
ADJUSTMENT SCREW
(UNDER CAP SCREW)

INLET

PRESSURE TAP

INLET

RESET BUTTON

N

atural Gas Flame Control

Control of burner flames on units utilizing natural gas is
achieved by moving the gas manifold to either increase or
decrease primary combustion air. Prior to flame adjustment,
operate unit with casing closed for about five minutes.
Operation can be viewed after loosening and pushing aside
the blue gas designation disc on rear of unit.

PILOT ADJUSTMENT
SCREW

OUTLET
PRESSURE
TAP

OUTLET

PILOT TUBING
CONNECTION

9

Heater Parts from ACF Greenhouses