GWS-090E
Gas-Fired Water Boiler –
Boiler Manual
26
Part Number 550-110-737/1108
12 Troubleshooting
continued
CHART 1
— Troubleshooting
POWER
light status
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 Weil-McLain sales
representative.
• Make sure service switch or circuit breaker is on or
fuses are good.
• Remove
120 VAC IN
plug on control module.
• Using voltmeter, check across top and bottom pins of
120 VAC IN
plug.
Does voltmeter indicate
120 VAC
?
No
Yes
No
Yes
No
Yes
Chart
2
Chart
6
TSTAT CIRC
light flashing
Chart
3
Chart
4
PRESS SWITCH
light flashing
FLAME
light flashing
For insufficient heat or no heat problem, go to
Chart 7
if
POWER
light is on steady, with no other
light flashing.
No
Yes
On steady
(not flashing)
No
Yes
— Usually indicates reversed 120 VAC polarity if POWER light flashes by itself —
Is
POWER
light off?
Is
POWER
light ...
Flashing
alone
Flashing with
another light
• Reconnect
120 VAC IN
plug.
• Remove
120 VAC IN
transformer
PRIMARY
plug on
control module.
• Using voltmeter, check across top and bottom pins of
PRIMARY
receptacle.
Does voltmeter indicate
120 VAC
?
• Reinstall
120 VAC
transformer
PRIMARY
plug.
• Remove
24 VAC
transformer plug on control module.
• Using voltmeter, check pins of plug.
Does voltmeter indicate
24 VAC
?
Replace control module.
Retest.
Replace transformer.
Retest and check for back
feed of voltage from
system wiring.
• Usually indicates po
larity on incoming
120 VAC
power
line is wrong.
•
TURN OFF POWER
at service switch or breaker, then
reverse the HOT and NEUT
RAL wires entering the
boiler in the J-box.
• Restore
POWER
at service switch or breaker.
Is
POWER
light flashing now?
Chart
5
