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6-577.4
5H75225A Rev. C
May, 2007
RESIDENTIAL OWNER’S MANUAL
gas-fired unit heaters
models HD, HDB, HDS, and HDC
All models approved for use in California by the CEC,
in New York by the MEA division, and in Massachusetts.
Unit heater is certified for residential and commercial
applications.
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
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.
WARNING
If the information in this manual is not
followed exactly, a fire or explosion may
result, causing property damage, personal
injury or death.
IMPORTANT
All installation and service of these
units MUST be performed by a qualified
installation and service agency.
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
WHAT TO DO IF YOU SMELL GAS:
• Open windows.
• Do not try to light any appliance.
• Do not touch any electrical switch; do not
use any phone in your building.
• Immediately call your gas supplier from
a neighbor’s phone. Follow the gas
supplier’s instructions.
• If you cannot 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.
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IMPORTANT
All installation and service of these
units MUST be performed by a qualified
installation and service agency.
INTRODUCTION AND GENERAL COMMENTS GENERAL OPERATIONAL INFORMATION
Congratulations on Your New Purchase
Thank you for choosing Modine’s low profile, tubular “Hot
Dawg” unit heater. We are convinced that you will be pleased
with the design and quality of this heater. You should receive
years of trouble-free heat and comfort from the Hot Dawg with
proper maintenance and care.
Keep the heater area clear:
1. Do not use the area around the heater for storage.
2. Never obstruct the air openings into the heater.
3. Never place any items (paper, tools, etc.) on top of the
heater. There are air openings on the top of the heater.
4. Do not place any combustible materials (paper, wood, cloth,
etc.) next to the heater or vent.
Supply Air:
1. Make certain that the fan guard in the rear of the heater is
unobstructed.
2. For optimum performance, do not completely close the
deflector blades. If needed, adjust the deflector blades
slightly to direct the air towards the ground.
3. When initially started in a cold environment, the air coming
out of the heater may not feel warm. As the temperature
in the environment increases, and as the heat exchanger
tubes become hot, the air temperature coming out of the
heater will increase.
Combustion Air: (Power Vented Unit Only)
This gas-fired unit heater must be supplied with adequate
combustion air. Today’s current construction techniques, which
result in tighter homes and buildings (or significantly less air
infiltration from the outside), makes it more important than
ever that heating equipment have adequate combustion air.
The installer of this unit heater has determined what it takes
to be assured that your unit heater has adequate combustion
air. If this heater has been installed in a confined space, two
permanent openings (one near the top of the enclosure and
one near the bottom) have been provided. These two openings
must freely communicate with areas having adequate
combustion infiltration from the outside. Do not block or alter in
any way the combustion air openings.
It is very important to abide by the following:
1. Do not block or alter in any way the combustion air
openings.
2. Refrain from creating excessive amounts of dust near the
heater (i.e. saw dust from sanding, cutting, etc.)
3. Do not use or store corrosive chemicals in the area near
the heater (these include pool chlorine, fertilizers, etc.)
4. Refrain from prolonged use of ventilation fans or hoods as
this may deplete the amount of combustion air.
Start Up - General
Before start up, it is important to read the “For Your Safety
Read Before Operating” message below. This message
also appears on the access cover of your HD gas-fired unit
heater. The message follows:
FOR YOUR SAFETY READ BEFORE OPERATING
WARNING: If you do not follow these instructions exactly,
a fire or explosion may result causing property damage,
personal injury or death.
A. This appliance does not have a pilot flame. It is equipped
with an ignition device which automatically lights the
burner.
B. BEFORE OPERATING smell all around the appliance area
for gas. Be sure to smell next to the floor because some
gas is heavier than air and will settle on the floor.
WHAT TO DO IF YOU SMELL GAS:
• Do not try to light any appliance.
• Do not touch any electric switch; do not use any
phone in your building
• Immediately call your gas supplier from a
neighbor's phone. Follow the gas supplier’s
instructions.
• If you cannot reach your gas supplier, call the fire
department.
C. Use your hand to move the gas control switch. Never use
tools. If the switch will not move, don’t try to repair it; call a
qualified technician. Force or attempted repair may result in
a fire or explosion.
D. Do not use this appliance if any part has been under water.
Immediately call a qualified service technician to inspect
the appliance and replace any part of the control system
and any gas control which has been under water.
The control operating sequence of your gas-fired unit heater is
as follows:
• Upon a call for heat from the thermostat, power is supplied
to the power exhaust motor.
• The unit will go through a pre-purge period.
• The igniter provides for the establishment of the flame
while the main valve in the control opens to allow gas flow
to the burners.
• If the fan motor has not already started, it will start shortly.
• If a burner flame is not sensed for any reason, the main
valve will close and there will be a short purge period
before ignition is tried again.
• If the flame is not sensed after four tries there will be at
least a one hour wait before ignition is tried again.
Shut Down - General:
TO TURN OFF GAS TO APPLIANCE
1. Set thermostat to lowest setting.
2. Turn manual shut-off valve located outside of the unit to the
closed position (see Figure 1).
3. Turn off all electric power to the appliance if service is to be
performed.
4. Remove access panel.
5. Turn the gas valve switch to the “OFF” position.
6. Replace the access panel.
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