39
Part Number 550-142-785/0812
GWI
Series 2
Gas-Fired Water Boilers –
Boiler Manual
12 Troubleshooting
continued
•
▲
TURN OFF POWER
▲
to boiler at service switch or
breaker.
•
Remove burner shield (see
Figure 25, item 4
,
page 42
for
location).
•
Verify inlet gas pressure at gas
valve:
Natural gas —
5.0" w.c. min/14.0"
w.c. max
Propane —
11.0" w.c. min/14.0"
w.c. max
Is gas present at gas valve inlet and
within above range?
CHART 6
— FLAME
light flashing and
POWER
light on steady
ALSO —
Troubleshooting failure to establish
main flame
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.
No
Yes
•
Is pilot flame visible through inspection port?
•
Are main manual shutoff valve and boiler gas valve open?
No
Yes
•
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
Yes
•
Boiler should be in
normal operating
sequence.
•
Observe operation
until thermostat is
satisfied and blower
has completed its
post-purge cycle.
•
Make sure ground wire
terminal is securely fastened
to control module mounting
screw.
•
Check the voltage across
terminals PV and C of the
gas valve.
Is 24 VAC present there?
No
Yes
•
Check the voltage across
terminals MV and C of the
gas valve.
Is 24 VAC present there?
No
Yes
No
Yes
•
Contact gas supplier to correct
pressure or gas supply.
•
If the wiring from the
control module to gas
valve is intact, replace the
control module.
•
Retest.
•
▲
TURN OFF POWER
▲
to boiler at service switch or breaker.
•
Check flame signal
—
Detach sense lead from ignition control
(
Figure 23, item 8, page 33
).
•
Connect
negative
lead of MICROAMMETER to control sense
terminal (
Figure 23, item 8, page 33
). 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
Yes
•
If the wiring from the
control module to gas
valve is intact, replace the
control module and retest.
•
Verify inlet gas pressure at gas valve:
Natural gas —
5.0" w.c. min/14.0" w.c. max
Propane —
11.0" w.c. min/14.0" w.c. max
Is gas present at gas valve inlet and within above range?
No
Yes
•
▲
TURN OFF POWER
▲
to boiler at service switch or
breaker.
•
Remove burner shield (see
Figure 25, item 4
,
page 42
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.
•
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.
•
If none of the previous steps
(including replacing pilot)
corrects problem, then replace
the control module, reinstall
burner shield and retest.
