Weil-McLain Boiler - Manual (Page 29)

Part Number 550-110-646/0607
Universal control systems — Control supplement
Troubleshooting
continued
Is damper harness securely plugged in at both
ends?
No Yes Secure connections.
Is 24VAC present across terminals C and Y on
transformer?
No Yes
Check for loose wire connections
or bad relay on transformer.
Is 24VAC present across terminal C and yellow wire
between damper connector and rollout thermal fuse
element?
No Yes
Check for open thermostat or circ. relay (where used) or check for
loose wire connections, defective spill switch or rollout thermal fuse
element, or open LWCO or high limit contacts.
If LWCO, spill switch or rollout thermal fuse element
contacts are open, determine cause and correct
condition. Failure to do so will cause severe personal injury, death,
or substantial property damage.
Check for out of round stack section.
Does motor rotate open?
No Yes Replace actuator.
Is damper rotated open?
No Yes
Is 24VAC present at Terminals
PV and MV/PV?
No Yes
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 Yes
Is spark present now?
Yes No Turn OFF supply voltage.
Re-test.
Check continuity of each wire in wiring
harness to damper. Does continuity exist
for each wire?
No Yes
Replace damper
wiring harness.
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 14. Does
boiler fire?
No Yes
Securely connect and
turn ON supply voltage.
Re-test.
Check spark wire. Is it securely
connected to ignition control?
No Yes
Is condition of spark
wire good (not brittle,
burned, or cracked)?
No Yes
Replace pilot assembly.
Replace ignition control.
Replace actuator.
Is spark gap 0.125” and
located in pilot gas stream?
No Yes
Replace pilot assembly.
Replace ignition
control.
Replace pilot assembly.
Is spark electrode ceramic
cracked?
No Yes
Turn ON supply voltage
and operate system
several complete cycles. FIGURE 14
1
4
2
5
3
6
CHART 2: NO SPARK — System does not work — With vent damper