14
STARTUP, ADJUSTMENTS, AND CHECKS
Heating Startup
This unit is equipped with an electronic ignition device to
automatically light the main burners. It also has a power
vent blower to exhaust combustion products.
On new installations, or if a major component has been
replaced, the operation of the unit must be checked.
Check unit operation as outlined in the following
instructions. If any sparking, odors, or unusual sounds are
encountered, shut off electrical power and check for wiring
errors, or obstructions in or near the blower motors. Duct
covers must be removed before operating unit.
Burner Limit Control
The burner temperature switch is mounted on the burner
box assembly to monitor the burner box temperature. It is
normally closed (electrically), auto-reset sensor. An input
to the control is provided by the normally closed blocked
burner switch. An open blocked burner switch interrupts
current to the gas valve which closes the valve. This switch
guards against the burner flames not being properly drawn
into the heat exchanger.
Secondary Limit Control
The secondary limit control is located on the top of the
blower scroll assembly. This control opens when elevated
temperatures are sensed. Elevated temperatures at the
control are normally caused by blower failure. The reason
for the opening should be determined and repaired prior to
resetting.
If the power to the unit is interrupted during the heating
cycle, it may cause the secondary limit to trip. Once the
blower compartment temperature drops below the limit
reset temperature, the limit will automatically reset.
Secondary
Control Limit
Back of Unit
Secondary Limit Control
Pre-Operation Checks
1. Close the manual gas valve external to the unit.
2.
Turn off the electrical power supply to the unit.
3. Set the room thermostat to its lowest possible setting.
4. Remove the heat exchanger door on the side of the
unit by removing screws.
5. This unit is equipped with an ignition device which
automatically lights the main burner. DO NOT try to
light burner by any other method.
6. Move the gas control valve switch to the OFF position.
Do not force.
7.
Wait five minutes to clear out any gas.
8. Smell for gas, including near the ground. This is
important because some types of gas are heavier
than air. If you have waited five minutes and you do
smell gas, immediately follow the warnings near the
beginning of this manual. If having waited for five
minutes and no gas smell is noted, move the gas
control valve switch to the ON position.
9. Replace the heat exchanger door on the side of the
unit.
10. Open the manual gas valve external to the unit.
11. Turn on the electrical power supply to the unit.
12. Set the thermostat to desired setting.
Gas Supply And Manifold Check
Gas supply pressure and manifold pressure with the
burners operating must be as specified on the rating plate.
Gas Supply Pressure Measurement
NOTE: Use adapter kit #0151K00000S to measure
gas pressure on White-Rodgers 36J22Y gas valves.
CAUTION
To prevent unreliable operation or equipment damage, the
inlet gas supply pressure must be as specified on the unit
rating plate with all other household gas fired appliances
operating.
The line pressure supplied to the gas valve must be within
the Inlet Gas Supply Pressure range specified. The supply
pressure can be measured at the gas valve inlet pressure
tap or at a hose fitting installed in the gas piping drip leg.
The supply pressure must be measured with the unit OFF.
To measure inlet pressure, use the following procedure.
