Weil-McLain 4 Series Manual page 28

EG • PEG • EGH Series 4
Troubleshooting
CHART 1: NO SPARK — System does not work — Without vent damper
Correct by making connections.
Check for open thermostat or circulator relay
(where used) or check for loose wire con-
nections, defective spill switch or rollout
thermal fuse element, or open LWCO or limit
contacts.
If LWCO, spill switch or rollout
thermal fuse element contacts
are open, determine cause and correct con-
dition. Failure to do so will cause severe per-
sonal injury, death, or substantial property
damage.
Replace ignition control.
Securely connect, then turn ON supply voltage and re-test.
Is spark gap 0.125" and located in pilot gas steam?
No
Replace pilot assembly, turn ON supply
voltage, operate system several complete
heat cycles.
8
continued
VISUALLY CHECK - is ground wire connected from
"GND (Burner)" to ignition control mounting screw;
and ground wire connected from transformer
Terminal "C" to case ground?
No
Is 24VAC present across Terminals 24V & 24V(GND)?
No
Open thermostat contacts for 15 seconds. Close thermo-
stat contacts - is 24 VAC across terminals PV & MV/PV?
Replace pilot assembly.
Yes
Replace ignition control.
Yes
Yes
No Yes
Turn OFF supply voltage.
Check spark wire. Is it securely connected
to spark transformer?
No
Is condition of spark wire good (not cut,
brittle, burned, or cracked)?
No
Is spark electrode ceramic cracked?
No
Replace pilot assembly, turn ON supply
voltage, operate system several complete
heat cycles.
Is the vent damper
plug in place?
No Yes
Replace damper
plug and retest.
Yes
Yes
Yes
Part Number 550-110-646/0607