Operating instructions

33
Part Number 550-142-784/0812
GWA Series 2 Gas-Fired Water Boilers – Boiler Manual
12 Troubleshooting – spark-ignited pilot boilers
Electrical shock hazard — Wherever you see TURN OFF POWER, follow the instructions. Failure to follow
instructions could result in severe personal injury, death or substantial property damage.
Problem is with incoming
electricity. Have licensed
electrician repair circuit.
Replace control module.
Retest.
Boiler should now
operate normally.
Have system checked by a
licensed electrician.
If problem persists, call your
local Williamson-Thermoflo
sales representative.
• Make sure service switch or circuit breaker is on or
fuses are good.
• Remove 120 VAC IN plug (Figure 17, Item 3,
page 32) on control module.
• Using voltmeter, check across black and white wire
pins of 120 VAC IN plug.
Does voltmeter indicate 120 VAC?
No Yes
No Yes
No Yes
Chart
3
Chart
6
TSTAT CIRC
light flashing
Chart
4
Chart
5
DAMPER
light flashing
For insufficient heat or no heat problem, go to
Chart 6, page 38, if POWER light is on steady,
with no other light flashing.
• Usually indicates polarity on incoming 120 VAC power
line is wrong.
•
TURN OFF POWER at service switch or breaker,
then reverse the HOT and NEUTRAL wires entering
the boiler in the J-box.
• Restore POWER at service switch or breaker.
Is POWER light flashing now?
No Yes
Flashing
alone
Flashing with
another light
On steady
(not flashing)
No Yes
Is POWER light off?
— Usually indicates reversed 120 VAC polarity if POWER light flashes by itself —
Is POWER light...
FLAME
light flashing
• Reconnect 120 VAC IN plug.
• Remove transformer plug (Figure 17, Item 2, page
32) on control module.
• Using voltmeter, check across left side top and
bottom pins of transformer receptacle.
Does voltmeter indicate 120 VAC?
• Reinstall transformer plug.
• Remove TSTAT transformer plug (Figure 17, Item 5,
page 32) on control module.
• Using voltmeter, check across left and right pins of
receptacle.
Does voltmeter indicate 24 VAC?
Replace control module.
Retest.
Replace transformer.
Retest.
CHART 1 — Spark-ignited pilot — Troubleshooting POWER light status