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
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 on page 4 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.
Open to | Manometer | |
Atmosphere | ||
Hose | ||
|
Outlet | High Fire Regulator | Regulator |
Adjust | ||
Pressure Boss |
| Vent |
Gas Supply And Manifold Check
Gas supply pressure and manifold pressure with the burners operating must be as specified on the rating plate.
Gas Inlet Pressure Check
Gas inlet pressure must be checked and adjusted in accordance to the type of fuel being consumed.
With Power And Gas Off:
1.Connect a water manometer or adequate gauge to the inlet pressure tap of the gas valve.
Inlet gas pressure can also be measured by removing the cap from the dripleg and installing a predrilled cap with a hose fitting.
With Power And Gas On:
2.Put unit into heating cycle and turn on all other gas consuming appliances.
| INLET GAS PRESSURE | |
|
|
|
Natural |
| Min. 5.0" W.C., Max. 10.0" W.C. |
|
|
|
Propane |
| Min. 11.0" W.C., Max. 13.0" W.C. |
NOTE: Inlet Gas Pressure Must Not Exceed the Maximum Value Shown.
If operating pressures differ from above, make necessary pressure regulator adjustments, check piping size, etc., and/ or consult with local utility.
Gas Line
Gas
Shutoff
Valve 
Gas Line
To Furnace
Open To
Atmosphere
Drip Leg Cap
With Fitting
Manometer Hose
Manometer
Measuring Inlet Gas Pressure
Alternate Method
Manifold Pressure Check
1Turn OFF gas to furnace at the manual gas shutoff valve external to the furnace.
Inlet 
Pressure Boss
A
Low Fire
Regulator Adjust
2. | Turn off all electrical power to the system. |
3. | Back outlet pressure test screw (inlet/outlet pressure boss) |
| out one turn (counterclockwise, not more than one turn). |
4. | Attach a hose and manometer to the outlet pressure boss |
| of the valve. |
5. | Turn ON the gas supply. |
6. | Turn on power and energize main (M) solenoid. Do not |
| energize the HI solenoid. |
|
| High Fire |
| Coaxial Coil | |
Manometer | Coil Terminal (HI) | ||||
Terminal (M) | |||||
| On/Off Switch |
|
| ||
|
| Common | |||
|
|
| Terminal (C) | ||
White-Rodgers Model 36G54 connected to Manometer
7. Measure gas manifold pressure with burners firing. Adjust |
manifold pressure using the Manifold Gas Pressure table |
shown below. |
13
