40
Part Number 550-142-785/0812
GWI
Series 2
Gas-Fired Water Boilers –
Boiler Manual
12 Troubleshooting
continued
CHART 7
—
Insufficient heat or no heat to system (
POWER
light on steady)
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.
•
Replace rollout switch.
•
Boiler is in standby.
•
Set thermostat to call for
heat and recheck
operation.
•
Verify
Sequence of
operation
,
Figure 18
,
page 23.
Replace control module.
Retest.
•
Has it been at least 5 minutes since setting thermostat to
call for heat? If not, wait 5 minutes. Is system heating?
•
Is thermostat set to call for heat? Remove thermostat
wires at boiler and check continuity across the two wires.
If circuit isn't closed, check external thermostat (zone
valve, relay, etc.) wiring. Correct problems and retry.
•
Reconnect external thermostat wiring at boiler.
Is thermostat circuit closed (continuity across wires)?
•
If you have sufficient heat
—
boiler should be in normal
operating sequence. (See normal sequence of operation,
Figure 18
, page 23.)
•
If you have less than sufficient heat
—
Is vent piping free of blockage?
No
Yes
•
Correct conditions and
recheck operation.
•
See
Figure 30
, page 38
for normal sequence of
operation.
•
Check heat loss
calculation versus boiler
size.
•
Clock gas input.
•
Replace control
module.
•
Retest.
•
Repair/replace
circulator. Retest.
•
Repair/replace
wiring. Retest.
•
Remove CIRCULATOR harness plug from
CIRCULATOR plug receptacle (
Figure 23, Item
7, page 33
). Check with voltmeter across pins of
control module receptacle.
Does voltmeter show 120 VAC across pins?
No
Yes
Is boiler System circulator operating?
•
Wait 5 minutes.
Is FLAME light on?
No
Yes
Is LIMIT light on?
No
Yes
Are all red lights off?
No
Yes
Wait 30 seconds.
Are all red lights off?
No
Yes
•
Replace control module.
•
Retest.
Yes
No
Yes
No
Yes
Check rollout switch
continuity
—
is switch
closed?
No
Yes
•
Check any other
limit controls wired
into the limit
circuit. If all are
OK, then replace
control module.
•
Retest.
If rollout thermal fuse element has
opened, determine cause and
correct condition. Failure to do so
will cause severe personal injury,
death or substantial property
damage.
No
•
Replace temperature
sensor.
•
Retest.
•
Check temperature
sensor for correct
resistance.
Are resistance values
correct?
