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ULTRA HIGH EFFICIENCY POWER VENT/POWER DIRECT VENT - SERVICE MANUAL
Technical Literature Department 46 of 52 Ashland City, TN © 2008
Servicing should only be performed by a Qualified Service Agent
FAULT MESSAGES (CONT)
DISPLAYED MESSAGE
CONDITION/INDICATES
CHECK/REPAIR
“Blocked Inlet”
The control system has detected open contacts at
the Blocked Intake air pressure switch - inadequate
supply of intake (combustion) air.
• If the water heater has been installed as a con-
ventional vent appliance - Ensure the intake air
connection screen is not clogged with debris.
See Service Notes - Venting on page 7.
• If water heater has been installed as a direct
vent appliance - check for restrictions, too many
equivalent feet, or too many elbows in the intake
air piping. Review venting installation section of
the Instruction Manual that came with the water
heater - see Table 1 on page 7 in this manual.
Ensure the vent/intake air piping has been
installed within manufacturers requirements.
• If water heater has been installed as a direct
vent appliance - temporarily disconnect the
intake air pipe at the blower connection on the
water heater - ensure the screen inside the
intake air connection was removed during
installation. See the Service Notes for venting
on page 7.
• Check all wiring between the Blocked Intake air
pressure switch and the CCB’s J6 Socket (page
36) pins 4 & 14. Perform close visual inspection
of the pins inside the plug and socket - ensure
plugs and sockets are mating properly and pro-
viding good contact. Repair/replace anything
worn or damaged.
• Review the air pressure switch information
beginning on page 18. Perform the pressure
switch test procedure for the Blocked Intake air
pressure switch - see pages 21 through 23.
Replace the Blocked Intake switch if defective.
• Call the technical support phone number shown
on the water heater labeling for further assis-
tance if the problem has not been corrected
after performing the procedures outlined here.