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 Valve |
|
On/Off |
|
Selector |
|
Switch |
|
INLET | OUTLET |
|
|
INLET | OUTLET |
Gas Valve
On/Off
Selector
Switch
White-Rodgers 36G22
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
The gas valve has a tapped opening to facilitate measurement of the manifold pressure. A “U” Tube manometer having a scale range from 0 to 12 inches of water should be used for this measurement. The manifold pressure must be measured with the burners operating.
To adjust the pressure regulator, remove the adjustment screw or cover on the gas valve. Turn out (counterclockwise) to decrease pressure, turn in (clockwise) to increase pressure. Only small variations in gas flow should be made by means of the pressure regulator adjustment. In no case should the final manifold pressure vary more than plus or minus 0.3 inches water column from the specified nominal pressure. Any major changes in flow should be made by changing the size of the burner orifices. The measured input rate to the furnace must not exceed the rating specified on the unit rating plate.
For natural gas, the manifold pressure must be between 3.2 and 3.8 inches water column (3.5 nominal).
For propane gas, the manifold pressure must be between 9.7 and 10.3 inches water column (10.0 nominal).
Gas Input (Natural Gas Only) Check
To measure the gas input use a gas meter and proceed as follows:
1.Turn off gas supply to all other appliances except the unit.
2.With the unit operating, time the smallest dial on the meter for one complete revolution. If this is a 2 cubic foot dial, divide the seconds by 2; if it is a 1 cubic foot dial, use the seconds as is. This gives the seconds per cubic foot of gas being delivered to the unit.
3.INPUT=GAS HTG VALUE x 3600 / SEC. PER CUBIC FOOT Example: Natural gas with a heating value of 1000 BTU per cubic foot and 34 seconds per cubic foot as determined by Step 2, then:
Input = 1000 x 3600 / 34 = 106,000 BTU per Hour. NOTE: BTU content of the gas should be obtained from the gas supplier. This measured input must not be greater than shown on the unit rating plate.
4.Relight all other appliances turned off in step 1. Be sure all pilot burners are operating.
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