Vulcan-Hart MHB24G Electric Steamer User Manual


 
VHX SERIES STEAMER - SERVICE PROCEDURES AND ADJUSTMENTS
F24700 (October 2001)Page 33 of 68
AIR PRESSURE SWITCH
ADJUSTMENT
The air pressure switch senses the pressure level
produced by the blower for combustion. When the
pressure is sufficient, the switch closes and supplies
power to the ignition control module. The gas
ignition sequence starts to light the gas pilot and
then main burner. If the gas pilot is not lighting
(valve not energized), the ignition control module
may not be receiving power, assuming the minimum
water level is satisfied. Check the air pressure
switch operation then adjust if necessary as outlined
in the procedure below.
1. Turn the power switch OFF.
2. Remove the left side panel from the cabinet
base.
A. Inspect the air intake to the blower for
debris build up and clogging.
1) If debris is found, clean it away from
the air intake.
B. Turn the power switch ON and verify main
burner ignition.
1) If burner ignites then no adjustment to
the pressure switch setting is
necessary.
2) If burner does not
ignite, proceed to
step 3.
3. Open the cabinet base door and turn the
ON/OFF knob for the main gas valve to OFF.
4. Adjust the air pressure switch setting as
follows:
A. Turn the adjustment screw fully clockwise
to the highest setting.
B. Slowly turn the adjustment screw
counterclockwise
until the pilot gas valve
energizes then add ½ turn to the
adjustment.
NOTE
: The screw head should not
extend out
past the screw housing.
1) If Pilot gas valve energizes, proceed
to step 5.
2) If Pilot gas valve does not
energize,
check the following:
a. Remove the lead wires from the
switch and verify with a meter
that the switch contacts are
closing with the blower ON. If
necessary, continue to turn the
adjustment screw several turns
counterclockwise
to CLOSE the
switch contacts.
b. If the switch contacts are not
closing, turn the power switch
OFF, remove the pressure
switch from the TEE and check
the air orifice for debris build up
and clogging. If debris is found,
clean it away from the orifice.