Weil-McLain EGH-105 Control Supplement page 28

VIII
Check-out procedure — troubleshooting
TS-2: No Spark — System (boiler with vent damper) does not work
Secure connections.
Check for loose wire connections or bad relay on
transformer.
Check for open thermostat, circulator relay, operating
control, limit control or LWCO. Check the CSD-1 control
panel, impulse relay and push-button switch.
If limit controls or water level controls
lockout on manual reset, determine cause
and correct condition. Failure to do so could
result in severe personal injury, death or
substantial property damage.
Check for out of round stack section. Does motor rotate
open?
No
Replace actuator.
Retest.
Open thermostat contacts for 30 seconds. Damper will
rotate to closed position. Close thermostat contacts.
Damper will rotate to open position. Is 24VAC present
across terminals PV and MV/PV?
No
Check continuity of each wire in wiring harness to
damper. Does continuity exist for each wire?
No
Replace damper
wiring harness.
Retest.
Replace ignition
control. Retest.
1 2 3
4 5 6
28
EGH-105 to EGH-125 EGH-105 to EGH-125 EGH-105 to EGH-125
EGH-105 to EGH-125 EGH-105 to EGH-125
Yes
Yes
Yes
Remove damper harness from
boiler wiring harness.
TEMPORARILY install jumper
between terminal 2 and
terminal 5 on damper plug in
boiler wiring harness. See
figure below. Does boiler fire?
No Yes
Temporary
Replace damper
jumper
actuator. Retest.
Control Supplement
Is damper harness securely plugged in at both ends?
No
Is 24VAC present across transformer terminals C & Y?
No
Is 24VAC present across terminal C and yellow wire on
damper connector?
No
Is damper rotated open?
No
Is 24VAC present across terminals PV and MV/PV?
No
Is spark present now?
No
Turn OFF supply voltage.
Electrical shock hazard. Failure to turn off
power before proceeding could cause
severe personal injury or death.
Securely connect
and turn ON supply
voltage. Retest.
Is condition of spark wire good
(not brittle, burned or cracked)?
Replace pilot
assembly. Retest.
Is spark gap 0.125" and
located in pilot gas stream?
No Yes
Replace pilot Replace ignition
assembly. control. Retest.
Turn ON supply voltage and operate
system several complete cycles.
Yes
Yes
Yes
Yes
Yes
Yes
Retest.
Check spark wire. Is it securely
connected to ignition control?
No Yes
No Yes
Is spark electrode
ceramic cracked?
No Yes
Replace
pilot
assembly.
Part Number 550-110-677/0299