Installation and Service Manual
9.If gas pressure is out of range, contact your gas utility, gas supplier, qualified installer or service agency to determine the necessary steps to provide proper gas pressure to the control.
10.If gas supply pressure is within normal range, remove the gas manometer and replace the pressure tap fittings in the gas control as indicated in the following steps.
11.Turn the power switch to the “OFF” position.
12.Turn gas valve knob to the “OFF” position.
13.Shut off gas supply at the manual gas cock in the gas piping to the unit. If fuel supply is L.P. gas, shut off gas supply at the tank.
14.Remove the manometer and related fittings from the “inlet” side of the gas valve, replace 1/8" hex plug in the gas valve and tighten.
15.Turn on the gas supply at the manual valve, turn on L.P. gas at the tank if required.
16.Turn the power switch to the “ON” position.
17.Turn the gas valve knob to the “ON” position.
18.Set the electronic temperature control or thermostat to call for heat.
WARNING: After completing any testing on the gas system, leak test all gas connections. Apply a soap/water solution to all gas connections while main burners are operating. Bubbles forming indicate a leak. Repair all leaks at once. Do not operate this unit with a leak in the gas train, valves or related piping.
Check burner performance by cycling the system while you observe burner response. Burners should ignite promptly. Flame pattern should be stable, see Burner Flames, page 40. Turn the system off and allow burners to cool, then cycle burners again to ensure proper ignition and flame characteristics.
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2 | INLET | |
1/8" HEX INLET | ||
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1 | PRESSURE TAP | |
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MANOMETER |
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GAS
VALVE
CONTROL
KNOB OUTLET
Figure 20 - Measuring Gas Supply Pressure at Combination Gas Valve
Gas Manifold Pressure Adjustment
IMPORTANT: The gas valves are referenced to the fan pressurized chamber by a hose connected from the vent of the gas valve regulator to the chamber pressure tap located on the front inside portion of the jacket. Reference the drawings in this section for component and connection points for pressure measurement. The referenced chamber pressure must be subtracted from the manifold pressure to obtain actual net manifold pressure for normal operation. A manometer or magnahelic gauge legible in 0.1" increments up to 10 inches w.c. is required to check and adjust the manifold pressure. The regulator cover screw on the gas valve must be in place and tight for the unit to operate properly.
1.Remove screws that fasten the control panel access door and remove the door.
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