Weil-McLain GOLD CGt Manual page 55

GOLD CGt Gas-Fired Water Boiler — Boiler Manual
11c
Troubleshooting — control module lights
CHART 7 — Insufficient heat or no heat to system (POWER light on steady)
Electrical shock hazard — Wherever you see
instructions could result in severe personal injury, death or substantial property damage.
• 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)?
No
Are all red lights off?
No Yes
Wait 30 seconds.
Are all red lights off?
No Yes
Replace control module.
Retest.
• If you have sufficient heat — boiler should be in normal
operating sequence. (See normal sequence of operation,
Figure 28, page 34.)
• If you have less than sufficient heat, first check 3-way valve to
be sure it is not diverting flow to tankless coil. If 3-way valve is
supplying tankless coil, check tankless limit to be sure it set
correctly. If 3-way valve and tankless heater low limit are set
and operating correctly —
Is vent piping free of blockage?
No
• Correct conditions and
recheck operation.
• See Figure 28, page 34, for
normal sequence of
operation.
• Wait for boiler water to cool to temperature 20 to 30 °F lower
than temperature set on limit switch.
Are limit switch contacts closed?
No
•
• Replace limit
switch.
• Also check setting on limit switch (should be
• Retest.
above 140°F.).
Part Number 550-110-290/0107
Yes
• Boiler is in standby.
• Set thermostat to call for heat
and recheck operation.
• Verify Sequence of
operation, Figure 28,
page 34.
Yes
• Check heat loss calculation
versus boiler size.
• Clock gas input.
Yes
TURN OFF POWER , follow the instructions. Failure to follow
Is boiler System circulator operating?
No
• Remove CIRCULATOR harness plug from
CIRCULATOR plug receptacle (Figure 35, Item 7,
page 48). Check with voltmeter across pins of control
module receptacle.
Does voltmeter show 120 VAC across pins?
No
• Replace control
module.
• Retest.
• Wait 5 minutes.
Is FLAME light on?
Yes
No
• Check ambient temperature
switch. If switch is open,
boiler room temperature is
too high. Check air
openings. Add additional
openings if needed to keep
room temperature within
limits.
• Check limit switch contacts
with continuity checker.
Are limit switch contacts
closed?
No Yes
• Replace rollout switch.
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.
Yes
Yes
• Repair/replace
circulator. Retest.
• Repair/replace wiring.
Retest.
No
Is LIMIT light on?
Yes
Check if 3-way valve is
allowing water to return to
boiler from the system. If not
replace 3-way actuator.
• Replace control module.
• Retest.
Check rollout switch continuity
— is switch closed?
No
• Check any other limit
controls wired into
the limit circuit. If all
are OK, then replace
control module.
• Retest.
(cont.)
Yes
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