Weil-McLain GOLD CGt Manual page 52

GOLD CGt Gas-Fired Water Boiler — Boiler Manual
11c
Troubleshooting — control module lights
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.
• Are main manual shutoff valve and boiler gas valve open?
No
• ▲TURN OFF POWER▲ to boiler at service switch or breaker.
• Open main manual shutoff valve and boiler gas valve (per
Operating instructions in this manual). Wait at least 45
seconds.
• Turn on power at service switch or breaker. Allow boiler to cycle.
Does FLAME light flash now?
No
• Verify inlet gas pressure at gas
• Boiler should be in
normal operating
sequence.
• Observe operation
until thermostat is
satisfied and blower
has completed its
post-purge cycle.
• ▲TURN OFF POWER▲ to
boiler at service switch or
breaker.
• Remove burner shield (see
Figure 37, page 58, for
location).
• Verify pilot gas line is not
kinked, obstructed or damaged
and is correctly attached to
pilot and gas valve.
• Verify pilot ignition electrode,
electrode ceramic and spark
lead wire from control are in
good condition. Spark gap
should be approximately 1/8".
• Correct any above problems,
replacing pilot if burner or
wiring is damaged.
• Reinstall burner shield to
operate boiler for retest after
any changes or corrections.
• If none of the above corrects
problem, then replace the
control module and retest.
52
CHART 6 — FLAME light flashing and POWER light on steady
ALSO — Troubleshooting failure to establish main flame
Yes
Yes
valve:
Natural gas — 5.0" w.c. min/14.0"
w.c. max
Is gas present at gas valve inlet and
within above range?
Yes No
• Contact gas supplier to correct
pressure or gas supply.
• ▲TURN OFF POWER▲ to boiler
at service switch or breaker.
• Remove burner shield (see
Figure 37, page 58, for
location).
• Verify pilot burner is securely
attached to pilot bracket, bracket is
securely attached to cross tie, and
there is no corrosion on the parts
which would affect the ground path
for flame sense.
• Verify that pilot flame rod, flame rod
ceramic and lead wire from control
module to flame rod are in good
condition.
• Correct any above problems,
replacing pilot if burner or wiring is
damaged.
• Is pilot flame visible through inspection port?
No
• Check the voltage across
terminals PV and PV/MV of
the gas valve.
Is 24 VAC present there?
Yes No
• If the wiring from the
control module to gas
valve is intact, replace the
control module.
• Retest.
• Verify inlet gas pressure at gas valve:
Natural gas — 5.0" w.c. min/14.0" w.c. max
Is gas present at gas valve inlet and within above range?
No
• ▲TURN OFF POWER▲ to boiler at service switch or breaker.
• Check flame signal — Detach sense lead from ignition control
(Figure 35, item 8, page 46 ).
• Connect negative lead of MICROAMMETER to control sense
terminal (Figure 35, item 8 , page 46 ). Connect positive lead
of MICROAMMETER to sense wire.
• DISCONNECT red wire connected to terminal MV of the gas
valve.
• Turn on power to boiler and allow to cycle. As soon as pilot is
burning, the MICROAMMETER should read at least 1.0
microamp.
Is flame signal at least 1.0 microamp?
No
• If none of the previous steps
(including replacing pilot)
corrects problem, then replace
the control module, reinstall
burner shield and retest.
(continued)
Yes
• Make sure ground wire
terminal is securely fastened
to control module mounting
screw.
• Check the voltage across
terminals MV and PV/MV of
the gas valve.
Is 24 VAC present there?
No Yes
Yes
Yes
• If the wiring from the
control module to gas
valve is intact, replace the
control module and retest.
Part Number 550-110-290/0501