Weil-McLain Boiler - Manual (Page 31)

1 Part Number 550-110-646/0607
Universal control systems — Control supplement
Troubleshooting
continued
Pilot assembly and ignition control must share common ground
with main burner. Nuisance shutdowns are often caused by
poor or erratic ground.
Check for good metal-to-metal contact between pilot burner
bracket and main burner, and between main burner and
burner rest.
•
Check ground lead from “GND (Burner)” terminal on ignition
control to ignition control mounting screw, and from “C”
on transformer to transformer case ground. Make sure
connections are clean and tight. If wire is damaged or
deteriorated, replace with No. 18 gauge moisture-resistant,
thermoplastic-insulated wire with 105°C minimum rating.
•
CHART 3
(continued)
: Procedure to check system grounding
CHART 4: PILOT LIGHTS — Main valve will not come on — With or without vent damper
No Yes
Are pilot valve connections correct and securely fastened?
Connect securely to terminals PV and
MV/PV on ignition control.
No Yes
Is inlet gas pressure at least 5.0” w.c. and no more than 14.0” w.c.?
No Yes
Is manual hand valve open?
Open manual hand valve.
Contact gas supplier to correct gas pressure.
No Yes
Is gas present at pilot burner assembly?
To check for gas at pilot —
Remove the wire to “MV”
on the ignition control. Use a match
taped to a long screwdriver or pilot
lighter rod to manually light the pilot.
Does the pilot light?
Make sure gas cock is in “ON” position and
pilot line is not kinked or obstructed. Check
for clean pilot orifice. If OK, replace the gas
valve.
No Yes
Is spark gap 0.125” and located in pilot
gas stream?
Replace pilot assembly.
Block any draft around the boiler.
Check for clean pilot orifice. •
•