AOS WPC - Tech Training
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Ashland City, TN © 2007
Servicing should only be performed by a Qualified Service Agent
VF BOILER SERVICE MANUAL
ERROR MESSAGES (CONT)
DISPLAYED MESSAGE
CONDITION/INDICATES
CHECK/REPAIR
“Flame Stg1” (cont)
Flame or ignition failure.
Error message displayed after 1 or 3 losses of flame
or after 1 or 3 failed trials for ignition. EMC 5000
control system will lock-out after 1 or 3 trials
depending on the SW1 #2 dip switch setting on the
MCB circuit board. (see page 30)
Important Service Reminder:
When performing any troubleshooting steps outlined
in this service manual always consider the wiring
and connectors between components. Perform a
close visual inspection of all wiring and connectors
to a given component before replacement.
Ensure wires were stripped before being crimped in
a wire connector, ensure wires are crimped tightly in
their connectors, ensure connection pins in sockets
and plugs are not damaged or worn, ensure plugs
and sockets are mating properly and providing good
contact.
Failure to perform this critical step or failing to
perform this step thoroughly often results in
needless down time, unnecessary parts
replacement, and customer dissatisfaction.
•
Ensure the 24 VAC gas valve is opening and
gas is flowing through the valve:
Secure power to the boiler. Remove the gas
pressure test plug at the outlet of the boiler’s 24
VAC gas valve. Install a barbed hose adapter fit-
ting in this test port. Connect a U-tube or digital
manometer to the barbed fitting.
Close the gas train shut off valve (see image on
page 23).
Turn power to the boiler back on - ensure there
is a call for heat present.
The blower will reduce speed as the igniter
warm up period begins. The gas valve is ener-
gized at the end of the igniter warm up period.
When the gas valve is energized a positive
pressure should be measured from the outlet
test port on the boiler’s 24 VAC gas valve (with
the gas train shut off valve closed). The mea-
sured pressure should be approximately the
same as supply gas pressure to the inlet of the
valve.
If there is no pressure increase when perform-
ing this test. Turn power to the boiler off. Close
the supply gas shut off valve to the boiler and
remove the boiler’s 24 VAC gas valve - clean/
remove any obstructions or debris from the inlet
and outlet of the gas valve. Ensure the supply
gas line to the boiler and the gas train inside the
boiler are not obstructed - clean/remove any
obstructions or debris.
If the gas valve is being energized (previous
page) and all the above tests have been per-
formed and there is no gas pressure increase at
the gas valve outlet during this test - call the A.
O. Smith technical information center for further
assistance at 800 527-1953.
REMEMBER TO RE-OPEN THE GAS TRAIN
SHUT OFF VALVE.
