Modine 246455 User Manual
WARNING
6-583.9
5H8000400000
July, 2016
INSTALLATION AND SERVICE MANUAL
gas-fired unit heaters
model HD and HDB
All models approved for use in California by the CEC and
in Massachusetts. Unit heater is certified for residential and
commercial applications.
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.
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. Do not locate ANY gas-fired units in areas
where chlorinated, halogenated, or acid
vapors are present in the atmosphere.
These substances can cause premature
heat exchanger failure due to corrosion,
which can cause property damage, serious
injury, or death.
FOR YOUR SAFETY
WHAT TO DO IF YOU SMELL GAS:
1. Open windows.
2. Do not try to light any appliance.
3. Do not touch any electrical switch; do
not use any phone in your building.
4. Immediately call your gas supplier
from a neighbor’s phone. Follow the gas
supplier’s instructions. If you can not reach
your gas supplier, call your fire department.
THIS MANUAL IS THE PROPERTY OF THE OWNER.
PLEASE BE SURE TO LEAVE IT WITH THE OWNER WHEN YOU LEAVE THE JOB.
IMPORTANT
The use of this manual is specifically
intended for a qualified installation and
service agency. All installation and service
of these units must be performed by a
qualified installation and service agency.
Inspection on Arrival
1. Inspect unit upon arrival. In case of damage, report it
immediately to the 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 upon arrival for conformance with description of
product ordered (including specifications where applicable).
Table of Contents
Inspection on Arrival ................................. 1
Special Precautions ................................. 2
SI (Metric) Conversion Factors......................... 3
Before You Begin ................................... 3
Unit Location....................................... 4
Combustible Material and Service Clearances ......... 4
Unit Mounting .................................. 5
Unit Installation ................................. 5
Venting ....................................... 6
Gas Connections............................... 12
High-Altitude Accessory Kit ....................... 13
Electrical ..................................... 15
Wiring/Blower Speed Adjustment .................. 16
Operation ........................................ 17
Unit Components .................................. 18
Dimensions....................................... 19
Service/Troubleshooting............................. 20
Unit Wiring Diagram ................................ 21
Model/Serial Number/Replacement Parts ............... 22
Commercial Warranty........................Back Cover
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
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.
DANGER
Appliances must not be installed where they may be exposed
to a potentially explosive or flammable atmosphere.
WARNING
1. Gas fired heating equipment must be vented - do not
operate unvented.
2. A built-in power exhauster is provided - additional external
power exhausters are not required or permitted.
3. If an existing heater is being replaced, it may be necessary
to resize the venting systems. Improperly sized venting
systems can result in vent gas leakage or the formation of
condensate. Refer to the National Fuel Gas Code ANSI
Z223.1 (NFPA 54) or CSA-B149.1 - latest edition. Failure to
follow these instructions can result in injury or death.
4. Under no circumstances should two sections of double wall
vent pipe be joined together within one horizontal vent system
due to the inability to verify complete seal of inner pipes.
5. 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.
6. Gas pressure to appliance controls must never exceed
14" W.C. (1/2 psi).
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. Disconnect power supply before making wiring connections
to prevent electrical shock and equipment damage.
9. 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.
10. Any original factory wiring that requires replacement must
be replaced with wiring material having a temperature
rating of at least 105°C.
11. Ensure that the supply voltage to the appliance, as indicated
on the serial plate, is not 5% greater than the rated voltage.
12. When servicing or repairing this equipment, use only
factory-approved service replacement parts. A complete
replacements parts list may be obtained by contacting
the factory. 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 owner's risk.
2
6-583.9
CAUTION
1. All literature shipped with this unit should be kept for
future use for servicing or service diagnostics. Do not
discard any literature shipped with this unit.
2. Consult piping, electrical, and venting instructions in this
manual before final installation.
3. Do not attach ductwork, air filters, or polytubes to any
propeller unit heater.
4. Clearances to combustible materials are critical. Be sure to
follow all listed requirements.
5. Do not locate units in tightly sealed rooms or small
compartments (commonly referred to as confined spaces)
without provisions 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 1,000 BTU/Hr
input rating of the unit with a minimum of 100 square inches
for each opening, whichever is greater.
6. Low profile heaters are designed for use in heating
applications with ambient startup temperatures between
-40°F and 90°F, and ambient operating temperatures
between 40°F and 90°F.
7. Do not install unit outdoors.
8. In garages or other sections of aircraft hangars, such
as offices and shops that communicate with areas used for
servicing or storage, keep the bottom of the unit at least
7' above the floor unless the unit is properly guarded
to provide user protection from moving parts. In parking
garages, the unit must be installed in accordance with
the standard for parking structures ANSI/NFPA 88A latest
edition, and in repair garages the standard for repair garages
NFPA 30A - latest edition (Formerly NFPA 88B). In Canada,
installation of heaters in airplane hangars must be in
accordance with the requirements of the enforcing authority,
and in public garages in accordance with the current
CSA-B149 codes.
9. 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 hangars and in
accordance with the requirements of the enforcing authority
and/or NFPA 409 - latest edition.
10. Installation of units in high humidity or salt water
atmospheres will cause accelerated corrosion, resulting in
a reduction of the normal life of the units.
11. Do not install units below 7' measured from the bottom of
the unit to the floor in commercial applications (unless
unit is properly guarded to provide user protection from
moving parts) and 5' measured from the bottom of the unit
to the floor in residential applications.
12. Be sure no obstructions block air intake and discharge of
unit heaters.
13. The minimum distance from combustible material is based
on the combustible material surface not exceeding 160°F.
Clearance from the top of the unit may be required to be
greater than the minimum specified if heat damage, other
than fire, may occur to materials above the unit heater at
the temperature described.
14. Allow 18" of clearance at rear (or 6" beyond end of motor at
rear of unit, whichever is greater) and access side to provide
ample air for combustion and proper operation of fan.
15. Installation 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 CSA-B149.1.
16. Purging of air from gas supply line should be performed as
described in the National Fuel Gas Code, ANSI Z223.1
(NFPA 54) - latest edition. In Canada, installation must be in
accordance with CSA-B149.1.
SPECIAL PRECAUTIONS / SI (METRIC) CONVERSION FACTORS
BEFORE YOU BEGIN
CAUTION
17. 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).
18. The unit should be isolated from the gas supply piping
system by closing its field installed manual shut-off valve.
This manual shut-off valve should be located within 6' of
the heater.
19. Turn off all gas before installing appliance.
20. Ensure that the supply voltage to the appliance, as
indicated on the serial plate, is less than 5% below the
rated voltage.
21. 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.
22. Service or repair of this equipment must be performed
by a qualified service agency.
23. Do not attempt to reuse any mechanical or electronic
ignition controllers which has been wet. Replace defective
controller.
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 acidic) 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 check most of the Possible Remedies in the trouble-
shooting guide listed in Table 19.1, refer to the applicable
sections of the manual.
CAUTION
1. All literature shipped with this unit should be kept for future
use for servicing or service diagnostics. Leave manual with
the owner. Do not discard any literature shipped with this unit.
2. Consult piping, electrical, and venting instructions in this
manual before final installation.
3. Do not attach ductwork, air filters, or polytubes to any
propeller unit heater.
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 CSA-B149.1.
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 (NFPA 54) - latest edition, or in Canada by a
licensed gas fitter.
2. This unit is certified with the controls furnished. For
replacements parts, please order according to the
replacement parts list on serial plate. Always know your
model and serial numbers. 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. The same burner is used for natural and propane gas.
SI (METRIC) CONVERSION FACTORS
To Convert Multiply By To Obtain
"W.C. 0.249 kPa
°F (°F-32) x 5/9 °C
Btu 1.06 kJ
Btu/ft3 37.3 kJ/m
Btu/hr 0.000293 kW
CFH (ft3/hr) 0.000472 m3/min
CFH (ft3/hr) 0.00000787 m3/s
CFM (ft3/min) 0.0283 m3/min
CFM (ft3/min) 0.000472 m3/s
To Convert Multiply By To Obtain
feet 0.305 m
Gal/Hr. 0.00379 m3/hr
Gal/Hr. 3.79 l/hr
3
gallons 3.79 l
Horsepower 746 W
inches 25.4 mm
pound 0.454 kg
psig 6.89 kPa
psig 27.7 "W.C.
6-583.9
3
UNIT LOCATION
UNIT LOCATION
DANGER
Appliances must not be installed where they may be exposed
to a potentially explosive or flammable atmosphere.
CAUTION
1. Clearances to combustible materials are critical. Be sure to
follow all listed requirements.
2. Do not locate units in tightly sealed rooms or small
compartments (commonly referred to as confined spaces)
without provisions 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 1,000 BTU/Hr
input rating of the unit with a minimum of 100 square
inches for each opening, whichever is greater.
3. Low profile heaters are designed for use in heating
applications with ambient startup temperatures between
-40°F and 90°F, and ambient operating temperatures
between 40°F and 90°F.
4. Do not install unit outdoors.
5. In garages or other sections of aircraft hangars such
as offices and shops that communicate with areas used for
servicing or storage, keep the bottom of the unit at least
7' above the floor unless the unit is properly guarded. In
parking garages, the unit must be installed in accordance
with the standard for parking structures ANSI/NFPA
88A-latest edition, and in repair garages the standard for
repair garages NFPA 30A - latest edition (Formerly NFPA
88B). In Canada, installation of heaters in airplane hangars
must be in accordance with the requirements of the
enforcing authority, and in public garages in accordance
with the current CSA-B149 codes.
6. 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 hangars and in
accordance with the requirements of the enforcing authority
and/or NFPA 409 - latest edition.
7. Installation of units in high humidity or salt water atmospheres
will cause accelerated corrosion, resulting in a reduction of
the normal life of the units.
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.
Location Recommendations
1. When locating the heater, consider general space and
heating requirements, availability of gas and electrical
supply, and proximity to vent locations.
2. When locating units, it is important to consider that the exhaust
vent piping must be connected to the outside atmosphere.
3. Be sure the structural support at the unit location site is
adequate to support the unit's weight. 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.
Table 4.1 Clearances
Unit Side Clearance To Recommended
Combustible Materials Service Clearance
Top and Bottom 1" 1"
Access Side 18" 18"
Non-Access Side 1" 1"
Rear 18" 18"
Vent Connector 4" 4"
5. Be sure that the minimum clearances to combustible
materials and recommended service clearances are
maintained. Units are designed for installation with the
minimum clearances as shown in Table 4.1.
6. Do not install units in locations where the gas ignition system
is exposed to water spray, rain, or dripping water.
7. Mounting height (measured from bottom of unit) at which
unit heaters are installed is critical. Refer to mounting
height and heat throw data on page 17 of this manual. The
maximum mounting height for any unit is that height above
which the unit will not deliver heated air to the floor.
Combustion Air Requirements
The National Fuel Gas Code defines an “unconfined space”
as a space whose volume is greater than 50 cubic feet per
1,000 Btu/Hr input of the installed appliance(s). A confined
space is 50 cubic feet or less per 1,000 Btu/Hr input of the
installed appliance(s).
It is not recommended to install these unit heaters into
residential confined spaces. This recommendation is due to the
concern that at some point in time, the combustion air openings
provided by the installer may become blocked or eliminated by
the owner, either intentionally or unintentionally. Despite this
recommendation, if these units are installed into a residential
confined space, see National Fuel Gas Code ANSI Z223.1
(NFPA 54) or CSA-B149.1 Installation Code - latest edition, for
detailed combustion air provisions. The installation must adhere
to these requirements.
Units installed in confined spaces in industrial/commercial
installations must be provided with two permanent openings
- one near the top and one near the bottom of the confined
space. Each opening should have a free area of not less than
one square inch per 1,000 Btu/Hr of the total input rating of all
units in the confined space, freely communicating with interior
areas that have adequate infiltration from the outside.
For further details on supplying combustion air to a confined
(tightly sealed) space or unconfined space, see the National Fuel
Gas Code ANSI Z223.1 (NFPA 54) or CSA-B149.1 Installation
Code - latest edition.
Turning The Unit 180° (Model Sizes 30-75 Only)
All units are produced at the factory with left-side controls (when
looking at the unit). If the installation requires the controls to be
on the right side, all heaters - with the exception of the HD/HDB
100 and 125 - can be turned over by following the instructions
below.
• Byturningtheunit180°fromthewayitwasreceivedfrom
the factory, the sides become opposite, but the front and
back remain in the same relative position. The bottom
panel now becomes the top panel and vice-versa.
• Removetheaccesspanel,turnit180°,andre-attachitto
the unit so that all the information labels can be read.
• Removethespringloadeddeflectorblades,turnthemover,
replace, and adjust so they are open and in a position to
direct the heated air down to the floor.
4
6-583.9
UNIT MOUNTING
CAUTION
1. Do not install units below 7' measured from the bottom of
the unit to the floor in commercial applications (unless
unit is properly guarded to provide user protection from
moving parts) and 5' measured from the bottom of the unit
to the floor in residential applications.
2. Be sure no obstructions block air intake and discharge
of unit heaters.
3. The minimum distance from combustible material is
based on the combustible material surface not exceeding
160°F. Clearance from the top of the unit may be required
to be greater than the minimum specified if heat damage,
other than fire, may occur to materials above the unit
heater at the temperature described.
4. Allow 18" clearance at rear (or 6" beyond end of motor
at rear of unit, whichever is greater) and access side to
provide ample air for combustion and proper operation
of fan.
Figure 5.2 - Unit Heater Turned 180°
(30-75 units only) (Access panel and heated air
outlet change sides)
1. Be sure the means of suspension is adequate to support
the weight of the unit (see page 18 for unit weights).
2. For proper operation, the unit must be installed in a level
horizontal position.
3. Clearances to combustibles as previously specified must be
strictly maintained.
4. For model sizes 30-75, before lifting the heater for
suspension, the mounting brackets must be installed as
follows (for bracket accessory installation on model sizes
100-125, see the latest revision of literature 6-594):
• For standard (left side) control access, remove the 3 screws
and mounting bracket along the top edge of both the front
and back of the unit. Install the front bracket as shown in
Figure 5.1 by aligning the screw holes on the bracket with
the screw holes on the top edge of the unit. Repeat for the
bracket on the back of the unit.
• For right side control access, remove the 3 screws and
mounting bracket along the top edge of both the front and
back of the unit. Turn the unit over and install the front
bracket as shown in Figure 5.2 by aligning the screw holes
on the bracket with the screw holes on the top edge of the
unit (originally the bottom edge). Repeat for the bracket on
the back of the unit.
5a. Suspension by screws/lag bolts: Secure the mounting
brackets to the ceiling joists or truss, using 1/4" screws with
1/2" washers. These unit mounting brackets are slotted to
accommodate joists on 16" or 24" centerlines.
Figure 5.1 - Unit Heater in Standard Mounting
Configuration (30-75 Units Only)
5b. Suspension by threaded rod: The unit can also be hung
with threaded rod utilizing the same mounting brackets.
Attach the threaded rod to the unit mounting brackets,
securing with a top and bottom nut. For model sizes 100125, the units are designed to be suspended by threaded
rod without the use of brackets. On each piece of 3/8"
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. Place 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 first installed onto the
threaded rod to prevent the rod from turning.
Next, drill holes into a steel channel or angle iron at the
same centerline dimensions as those chosen for the heater
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, lock washers and nuts,
or a washer with double nut arrangement.
NOTE: A pipe hanger adapter kit, shown in Figure 5.3, is
available as an accessory. One kit consists of two drilled
3/4" IPS pipe caps and two 3/8" - 16 x 1-3/4" capscrews
to facilitate threaded pipe suspension. Two kits would be
required to install one unit.
5c. Shelf mounted units: The unit heater can also be installed
on a shelf. The mounting brackets will need to be attached
to the heater the same manner as explained in note #4,
however, to mount on a shelf the brackets must go on the
bottom of the heater. The brackets must be affixed to the
shelf using similar screws (1/4" screw with 1/2" washer) as
overhead joist or truss mounting. Be sure all clearance to
combustible requirements are met.
Figure 5.3 - Unit Heater Suspension Methods
(Threaded Rod) (Pipe Adaptor Kit)
6-583.9
5
INSTALLATION - VENTING
WARNING
1. Gas fired heating equipment must be vented - do not
operate unvented.
2. A built-in power exhauster is provided - additional external
power exhausters are not required or permitted.
3. If an existing heater is being replaced, it may be necessary
to resize the venting systems. Improperly sized venting
systems can result in vent gas leakage or the formation of
condensate. Refer to the National Fuel Gas Code ANSI
Z223.1 (NFPA 54) or CSA-B149.1 Installation Code - latest
edition. Failure to follow these instructions can result in
serious injury or death.
4. Under no circumstances should two sections of double wall
vent pipe be joined together within one horizontal vent system
due to the inability to verify complete seal of inner pipes.
CAUTION
Installation 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 CSA B149.1.
Model HD/HDB unit heaters must be vented with the proper
passageway as described in these instructions to convey
flue gases from the unit or the vent connector to the outside
atmosphere.
The venting instructions are organized in sections, based on
installation type. The sections are identified as follows:
Instructions Applicable Installation Instructions
Section by Vent System Type
A General instructions for ALL installations
B VERTICAL Category I vent systems ➀
C HORIZONTAL Category III vent systems ➀
➀ The difference between Vertical Category I and Horizontal Category III will be
identified in "Section A - General Instructions - All Units".
Section A – General Instructions – All Units
A1. If the unit heater being installed is replacing existing
equipment and using the existing vent system from that
equipment, inspect the venting system for proper size and
horizontal pitch, as required in the National Fuel Gas Code
ANSI Z223.1 (NFPA 54) or CSA-B149.1 Installation Codelatest edition and these instructions. Determine that there
is no blockage or restriction, leakage, corrosion and other
deficiencies which could cause an unsafe condition.
A2. The vent pipe should be galvanized steel or other suitable
corrosion resistant material (except for Horizontal Category
III vent systems, which will be covered in “Section C –
Horizontal, Category III Vent System Installation”). Follow
the National Fuel Gas Code for minimum thickness of vent
material. The minimum thickness for connectors varies
depending on the pipe diameter. Do not vent unit with PVC
or other forms of plastic venting material.
A3. All heaters come with a factory installed vent adapter for
attaching the vent pipe to the heater. Attach the vent pipe
to the adapter with 3 non-corrosive screws. (Drill pilot holes
through the vent pipe and adapter prior to screwing in
place).
A4. Refer to Table 6.1 for total equivalent vent pipe lengths,
making the vent system as straight as possible. The
equivalent length of a 3" elbow is 1' and for a 4" elbow is 5'.
Table 6.1 - Vent Pipe Diameters and Total Equivalent
Vent Pipe Lengths For Horizontal Venting Systems
Model Size Vent Pipe Diameter
30-75 3" 3' 30'
100-125 4" 3' 30'
Minimum
Eqv. Length
A5. A minimum of 12" straight pipe is recommended from the
flue outlet before turns in the vent pipe.
A6. Horizontal sections of vent pipe are to be installed with a
minimum downward slope from the appliance of 1/4 inch
per foot and suspended securely from overhead structures
at points not greater than 3' apart.
A7. Fasten individual lengths of vent together with at least 3
corrosion-resistant sheet metal screws.
A8. Keep single wall vent pipe at least 6" from combustible
materials. For double wall vent pipe, follow the vent
pipe manufacturer’s clearances to combustibles. The
minimum distance from combustible materials is based
on the combustible material surface not exceeding 160°F.
Clearance from the vent pipe (or the top of the unit) may be
required to be greater than 6" if heat damage other than fire
could result (such as material distortion or discoloration).
A9. Avoid venting through unheated space when possible.
When venting does pass through an unheated space or
if the unit is installed in an environment that promotes
condensation, insulate runs greater than 5' to minimize
condensation. Inspect for leakage prior to insulating and
use insulation that is noncombustible with a rating of not
less than 400°F. Install a tee fitting at the low point of the
vent system and provide a drip leg with a clean out cap as
shown in Figure 8.1.
A10. When the vent passes through a combustible INTERIOR
wall or floor, a metal thimble 4" greater than the vent
Maximum
Eqv. Length
Figure 6.1 - Venting Through Combustible Roof
or Wall
Single Wall Vent Pipe
Flashing
Listed
Thimble
Single
Wall
Non-Residential Single Wall Vent
Pipe Terminating with Double Wall
Vent Pipe ➀
Clearance Specified
by Type B Vent Mfg.
Agency Approved Vent
Kit or Single Wall Vent
Pipe
➀ See Instruction A10 for attaching single wall pipe to double wall pipe
Listed
Thimble
Listed
Terminal
Double Wall Vent Pipe ➀
Flashing
Clearance Specified
by Type B Vent Mfg.
Double
Wall
Single
Wall
Listed
Terminal
Listed
Terminal
Listed
Terminal
6
6-583.9
INSTALLATION - VENTING
diameter is necessary. If there is 6' or more of vent pipe in
the open space between the appliance and where the vent
pipe passes through the wall or floor, the thimble need only
be 2" greater than the diameter of the vent pipe. If a
thimble is not used, all combustible material must be cut
away to provide 6" of clearance. Where authorities have
jurisdiction, type B vent may be used for the last section
of vent pipe to maintain clearance to combustibles while
passing through wall or floor (see Figure 6.1). Any material
used to close the opening must be noncombustible.
A11. The following are general instructions for double wall
(type B) terminal pipe installation:
How to attach a single wall vent terminal to double wall
(type B) vent pipe:
1. Look for the “flow” arrow on the vent pipe.
2. Slide the vent terminal inside the exhaust end of the
double wall vent pipe.
3. Drill 3 holes through the pipe and the vent terminal.
Using 3/4" long sheet metal screws, attach the cap to
the pipe. Do not over tighten.
How to connect a single wall vent system to double
wall (type B) vent pipe:
1. Slide the single wall pipe inside the inner wall of the
double wall pipe.
2. Drill 3 holes through both walls of the single and double
wall vent pipes. Using 3/4" sheet metal screws, attach
the two pieces of pipe. Do not over tighten.
3. The gap between the single and double wall pipe must
be sealed, but it is not necessary to fill the full volume
of the annular area. To seal, run a large bead of 400°F
silastic around the gap.
A12. Vent termination clearances must be maintained:
Table 7.1 - Vent Termination Clearances
Minimum Clearances for
Structure Vent Terminal Location
Forced air inlet within 10 feet 3 feet above
Combustion air inlet of another
appliance 6 feet all directions
Door, window, gravity air inlet, 4 feet horizontal and below
or any building opening 1 foot above
Electric meter, gas meter, gas 4 feet horizontal (U.S.)
regulator, and relief equipment ➀ 6 feet horizontal (Canada)
Gas regulator ➀ 3 feet horizontal (U.S.)
6 feet horizontal (Canada)
Adjoining building or parapet wall 6 feet all directions
Adjacent public walkways 7 feet all directions
Grade (ground level) 3 feet above
➀
Do not terminate the vent directly above a gas meter or regulator.
A18. In addition to following these general instructions, specific
instructions for Vertical Category I or Horizontal Category III
vent systems must also be followed. Table 7.3 outlines the
differences:
Table 7.3 - ANSI Unit Heater Venting Requirements
Category Description Venting Requirements
I Negative vent pressure Follow standard
Non-condensing venting requirements.
II Negative vent pressure Condensate must
Condensing be drained.
III Positive vent pressure Vent must be gas tight.
Non-condensing
IV Positive vent pressure Vent must be liquid and
Condensing gastight. Condensate
must be drained.
Note: Vent connectors serving Category I appliances shall not be connected into
any portion of mechanical draft systems operating under positive pressure.
Vertical Category I Vent System Determination
• Verticalventsystemsterminatevertically(up).
• Thehorizontalportionoftheventruncannotexceed75%
of the vertical rise (Example: If the vent height is 10', the
horizontal portion of the vent system cannot exceed 7.5').
• Theventterminatesaminimumof5’abovetheventconnector
on the unit.
• IftheventsystemtobeinstalledmeetsALLthesecriteria
(an example is shown in Figure 9.1), proceed to “Section B –
Vertical Vent System Installation”. For all other cases, proceed
to the next section for Horizontal Category III Vent System
Determination:
Horizontal Category III Vent System Determination
•Horizontalventsystemsterminatehorizontally(sideways).
•Aventsystemthatterminatesverticallybuthasahorizontal
run that exceeds 75% of the vertical rise is considered
horizontal.
Horizontal vent configurations are Category III. For residential
installations, this requires the use of an agency approved
(UL1738) Category III vent system. Additional requirements,
including those for commercial and industrial installations are
covered in “Section C – Horizontal, Category III Vent System
Installation”.
A13. Do NOT use dampers or other devices in the vent or
combustion air pipes.
A14. Precautions must be taken to prevent degradation of
building materials by flue products.
A15. Single wall vent pipe must not pass through any
unoccupied attic, inside wall, concealed space, or floor.
A16. Uninsulated single wall vent pipe must not be used
outdoors for venting appliances in regions where the 99%
winter design temperature is below 32°F.
A17. The vent terminal must be:
Table 7.2 - Vent Terminals
Model Size Modine PN Other Listed Terminals
30-75 5H0722850005 Gary Steel 1092
100-125 5H0722850001 Gary Steel 1092
6-583.9
7
INSTALLATION - VENTING
Section B – Vertical Vent System Installation
B1. This section applies to vertically vented Category I
vent systems and is in addition to “Section A – General
Instructions – All Units”.
B2. Vertical vent systems terminate vertically, and must be
sized in accordance with the National Fuel Gas Code, ANSI
Z223.1 (NFPA 54) - latest edition.
B3. The horizontal portion of the vent run cannot exceed 75%
of the vertical rise (Example: If the vent height is 10', the
horizontal portion of the vent system cannot exceed 7.5').
B4. It is recommended to install a tee with drip leg and clean out
cap as shown in Figure 8.1.
B5. The vent terminates a minimum of 5’ above the vent
connector on the unit.
B6. All vertically vented heaters that are Category I must be
connected to a chimney or vent complying with a recognized
standard, or a lined masonry (or concrete) chimney with
a material acceptable to the authority having jurisdiction.
Venting into an unlined masonry chimney is not permitted.
Refer to the National Fuel Gas Code for common venting
and pages 11-12 of this manual.
B7. Use a listed vent terminal to reduce down drafts and
moisture in the vent.
B8. Double wall vent pipe is recommended, although single wall
can be used if the requirements of the National Fuel Gas
Code are followed.
B9. Vertical vents must terminate a minimum horizontal and
vertical distance from roof lines and adjacent walls or
obstructions. These minimum distances are outlined as
follows (based on National Fuel Gas Code requirements for
vents with diameters less than 12”):
•Fordouble wall vent pipe and 8' or greater horizontal
distance to any vertical wall or similar obstruction, the vent
must terminate above the roof in accordance with Figure
8.1 and Table 8.1.
•Fordouble wall vent pipe and less than 8' horizontal
distance to any vertical wall or similar obstruction, the vent
must terminate at least 2' above the highest point where it
passes through a roof of a building and at least 2' higher
than any portion of a building within a horizontal distance of
10' (see Figure 8.1).
Figure 8.1 - Vertical Vent Termination for Double
Wall Vent Pipe and Greater Than or Less Than 8’
Horizontally From a Vertical Wall or Obstruction
IF DISTANCE TO ADJACENT WALL IS
LESS THAN 8 FEET, THEN VENT MUST
TERMINATE AT LEAST 2 FEET ABOVE
THE HIGHEST POINT OF THE WALL
THAT IS WITHIN 8 FEET HORIZONTAL.
OTHERWISE, REFER TO TABLE 8.1 FOR
"H" DIMENSION.
LISTED TERMINAL
"H" MIN*
(SEE TABLE 8.1)
TEE WITH DRIP LEG
AND CLEANOUT CAP
"H" MIN*
(SEE TABLE 8.1)
LISTED TERMINAL
ROOF FLASHING
X
ROOF PITCH IS:
X / 12
ROOF FLASHING
USE LISTED THIMBLE
THROUGH CEILING
AND ROOF
12
USE LISTED THIMBLE
THROUGH ROOF
Table 8.1 - Minimum Height from Roof to Lowest
Discharge Opening
Rise X (in) Roof Pitch Min Height H (ft) ➀
0-6 Flat to 6/12 1.00
6-7 6/12 to 7/12 1.25
7-8 7/12 to 8/12 1.50
8-9 8/12 to 9/12 2.00
9-10 9/12 to 10/12 2.50
10-11 10/12 to 11/12 3.25
11-12 11/12 to 12/12 4.00
12-14 12/12 to 14/12 5.00
14-16 14/12 to 16/12 6.00
16-18 16/12 to 18/12 7.00
18-20 18/12 to 20/12 7.50
20-21 20/12 to 21/12 8.00
➀ Size according to expected snow depth.
8
6-583.9
BACK VIEW
4" MIN
USE LISTED THIMBLE
THROUGH CEILING
TEE WITH DRIP LEG
AND CLEANOUT CAP
12" MIN
RECOMMENDED
DOWNWARD SLOPE
1/4" PER FOOT
TOWARD DRIP LEG
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