Gas Pressure Requirements
The pressure furnished to the main gas valve must not exceed
13.9" wc. When the supply pressure is above 13.9" wc, a high
pressure regulator must precede the appliance gas pressure
regulator. The inlet gas pressure must not exceed the maximum
pressure rating of the high pressure regulator, and the outlet
pressure must furnish gas to the appliance pressure regulator
within the pressure range mentioned above.
Gas Piping
Gas piping must be sized to provide the minimum required
pressure at the burner when the burner is operating at maximum
input. Consult your local utility on any questions on gas pressure
available, allowing piping pressure drops, and local piping
requirements .
The proper size piping must be run from the meter to the gas
burner without reductions. Undersized piping will result in
inadequate pressure at the burner. The pressure will be at its
lowest when it is needed the most, at times of maximum demand.
Therefore, it can cause intermittent hard-to-find problems because
the problem may have left before the service technician has
arrived. Avoid the use of bushings wherever possible.
Remove all burrs and obstructions from pipe. Do not bend pipe;
use elbows or other pipe fittings to properly locate pipe.
A drip leg and a manual shut-off must be installed in the vertical
line before each burner such that it will not freeze. Install unions
so gas train components can be removed for service. All pipe
threads must have a pipe dope which is resistant to the action of
Propane gas. After installation, pressurize the piping as required
and test all joints for tightness with a rich soap solution. Any
bubbling is considered a leak and must be eliminated. Do not use
a match or flame to locate leaks.
Auxiliary Limit Switch Function
The auxiliary limit switch is a manually resetable switch and is
designed to trip in the event of a supply fan failure. It should not
trip during any other conditions. In the event of a blockage to the
return or discharge air, the primary limit, which is an automatic-
reset type, is designed to trip.
Should there be a fan failure which results in the tripping of the
auxiliary limit, the limit must be manually reset to resume function
of the unit.
On the Rebel A cabinet (3-6 ton), the auxiliary limit resides in
the fan compartment between the furnace heat exchanger and
the fan. To access the switch, the fan compartment door must
be opened. Be sure all power to the unit is disconnected before
opening the fan compartment door.
Figure 31: 3–6 Ton—Auxiliary Limit Switch
Once the fan compartment door is opened the auxiliary limit
switch can be found behind the supply fan on a bracket mounted
to the cabinet wall.
Depressing the red button on the auxiliary limit will reset the limit
and allow the furnace to be powered. The furnace should now
respond to a call for heat.
Figure 32: 7–15 Ton—Auxiliary Limit Switch
Again, the red button must be depressed in order to reset the limit
and allow the furnace to be powered.
DANGER
If you do not follow these instructions exactly, a fire or
explosion may result causing property damage, personal
injury, or loss of life .
A .
This appliance does not have a pilot. It is equipped with an
ignition device which automatically lights the burner. Do not
try to light the burner by hand.
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 only your hand to push in or turn the gas control knob.
Never use tools. If the knob will not push in or turn by hand,
don’t try to repair it, call a qualified service 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 to replace any part of the control system and
any gas control which has been under water.
DANGER
The spark ignitor and ignition control are high voltage. Keep
hands and tools away to prevent electrical shock. Shut off
electrical power before servicing any of the controls. Failure
to adhere to this warning can result in personal injury or death.
View of supply fan
with aux limit behind,
mounted on a bracket
off the cabinet wall
The auxiliary limit on the
B cabinet (7-15 ton) is in
the furnace compartment
(vestibule) above the furnace
IM 1125-6 • REBEL ROOFTOPS 30
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