Vulcan-Hart VHX24G5, MHB24G manual Pressure Readings Inches W.C

VHX SERIES STEAMER - SERVICE PROCEDURES AND ADJUSTMENTS

4.After the main burner lights, allow the boiler to reach operating pressure then turn the ON/OFF knob for the main gas valve to OFF.

5.Restart the ignition sequence by "rapidly" turning the power switch OFF then back ON. A rapid switching is needed to keep the boiler from starting automatic blowdown.

A.Press the reset switch to start the ignition process.

6.After the pilot burner lights, compare the manometer pressure reading to the pressure chart near the end of this procedure.

NOTE: The pilot gas valve operates on a time delay circuit and will only be energized for approximately 15 seconds to light the main burner then shut OFF. The pilot pressure reading must be taken while the pilot valve is energized within this time interval. After the main burner ignition time expires, the ignition control module will sense there is no flame present and will then try to re-establish a flame to light the main burner. This cycle will continue to repeat until the main gas valve is turned back ON.

A.If the pressure is not correct, proceed to step 7 to adjust.

B.If the pressure is correct, turn the power switch OFF, replace the adjustment screw cap and pilot pressure plug tap to the gas valve. Turn the knob on the main gas valve back to ON.

7.Remove the adjustment screw cap to access the pressure adjustment screw.

8.With the burner lit, set the pressure as outlined below.

A.To increase pressure, turn the screw clockwise.

B.To decrease pressure, turn the screw counterclockwise.

NOTE: Accurate gas pressure adjustments can only be made with the gas ON and the burner lit.

	PRESSURE READINGS (INCHES W.C.)
GAS TYPE	PILOT	LINE
		MINIMUM
	MANIFOLD		MAX
		RECOMMENDED
Natural	3.5	7.0	14.0
Propane	3.5	11.0

NOTE: If the incoming line pressure is less than the minimum recommended, then the manifold pressure can not be set correctly.

9.Once the correct pressure has been set, turn the gas supply and power switch OFF. Replace the adjustment screw cap and pilot pressure plug tap on the valve.

10.Turn the knob on the main gas valve to ON, the gas supply ON and check for proper operation.

Page 35 of 68 F24700 (October 2001)