AOS WPC - Tech Training
51 of 72
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
“Blower Prov Stg1”
Blower IS NOT Starting
(If the blower is starting proceed to the “Blower Prov
Stg1” Blower Is Starting tables)
IMPORTANT SERVICE NOTE:
BEFORE performing any of the check/repair
procedures in the right column of this table; review
the VFD and Blower Operation section in this
manual on page 11. Also review the Config Key
information on page 14 and the VFD/MCB
connections and service notes contained on page
34. Understanding how the MCB and VFD work
together to operate the blower is necessary.
Operational Note:
If the Normally Open Low Blower Prover or High
Blower Prover pressure switch contacts (circuits) are
closed at the beginning of the heat sequence prior to
the MCB initiating blower operation for the pre purge
operating state; the MCB will not initiate blower
operation in this condition - the MCB will declare a
fault condition and lock out. The “Blower Prov Stg1”
error message will be displayed on the UIM.
See blower prover switch information on page 24
and the Sequence of Operation on page 15
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.
•
If the MCB and VFD passed all tests above and
the blower motor will not start and is hot to the
touch - let the blower motor cool off and try
starting the boiler again later after the blower
motor has had time to cool down. If the blower
motor hums or tries to start but the shaft will not
turn - disassemble the blower housing - check
for/remove any debris that could be preventing
the blower wheel from spinning free.
Check the blower wheel for damage or binding/
catching against the blower housing. Adjust/cor-
rect any blower wheel alignment problems if
possible.
If the blower wheel is damaged or binding and
adjustment is not possible - replace the blower.
•
Check to see if the blower motor shaft will spin
free - if the blower motor shaft is seized -
replace the blower.
•
If the MCB and VFD passed all tests above and
the blower comes on and runs yet overheats
and is cutting out on thermal overload - replace
the blower.
