VHX SERIES STEAMER - SERVICE PROCEDURES AND ADJUSTMENTS
MAIN BURNER IGNITION
CHECKS
The complete gas burner assembly is located inside the heat exchanger casting in the boiler. The perforated burner head functions as both pilot and main gas burner. The inner portion of the perforated burner head serves as the pilot to light the main burner during the trial for ignition. Once the main burner lights, the flame encompasses the entire perforated burner head and the pilot flame extinguishes.
If burner ignition problems are encountered, perform the following checks to ensure components are adjusted properly.
1.Turn power switch ON and allow the boiler to fill.
2.Verify "low water" and "high pressure" safety circuits are satisfied.
A.Water Level in boiler.
1)Approximately one visible inch of water in the sight glass.
2)Auxiliary LLCO is satisfied.
a.N2 on relay board ON (low water safety circuit satisfied).
b.LED on auxiliary water level board ON.
B.High Limit Pressure Switch
1)Zero reading on boiler pressure gauge.
NOTE: Burner cycles ON at less than or equal to 8 PSI and OFF at 10 PSI.
NOTE: High Limit Pressure Switch automatically resets at approximately 12 PSI.
C.Press the reset switch to reset the safety circuits.
NOTE: Hi Pressure and low water lights on front control panel should be OFF.
1)N3 on relay board ON (high pressure safety circuit satisfied).
3.Verify blower is running and its operation is quiet.
NOTE: A "noisy" blower rotation may indicate bearing wear and reduce air pressure output.
A.N12 on relay board ON (120VAC supplied to the blower).
4.Verify air pressure switch is CLOSED.
A.N13 on relay board ON (air pressure switch CLOSED and condition satisfied).
B.Pilot gas valve energized and ignition sequence starts.
NOTE: If N13 is not ON or Pilot gas valve is not energized, then check the air pressure switch setting as outlined under "AIR
PRESSURE SWITCH ADJUSTMENT".
5.Verify 24VAC to ignition module and pilot valve.
A.N1 on relay board ON (24VAC is being supplied for the system).
B.N13 on relay board ON (24VAC is being supplied to the ignition module).
C.N14 & N15 on relay board ON (24VAC is being supplied to the pilot ignition timing circuit and the pilot valve.
6.Verify spark and pilot ignition.
A.If pilot lights, proceed to step 7.
B.If sparking occurs but pilot does not light, then check the pilot pressure setting as outlined under "GAS PILOT PRESSURE ADJUSTMENT".
C.If spark is not occurring:
1)Restart power ON sequence by "rapidly" turning the power switch OFF then back ON. A rapid switching is needed to keep the boiler from starting automatic blowdown.
2)Remove ignition cable boot from the ignitor rod terminal and check ignitor position in the burner head assembly.
3)Measure distance the ignitor terminal extends past the ignitor nut. Distance should measure approximately 3/4" to 7/8". See diagram 5898 "COMPLETE BURNER ASSEMBLY" at the end of this procedure.
NOTE: Touch ignitor terminal only and not the ceramic insulator.
a.If distance is ok, proceed to step 5) below and perform step "a" and "b" then continue with step "6)".
b.If distance is other than stated, loosen ignitor nut, set the ignitor position and then
c.
4)Press reset switch to start the ignition process.
F24700 (October 2001) |
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