Vulcan-Hart MHB24G Electric Steamer User Manual


 
VHX SERIES STEAMER - SERVICE PROCEDURES AND ADJUSTMENTS
F24700 (October 2001)Page 35 of 68
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.
GAS TYPE
PRESSURE READINGS (INCHES W.C.)
PILOT
MANIFOLD
LINE
MINIMUM
RECOMMENDED
MAX
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.