SERVICE HANDBOOK

ULTRA HIGH EFFICIENCY POWER VENT/POWER DIRECT VENT - SERVICE MANUALFAULT MESSAGES (CONT)DISPLAYED MESSAGECONDITION/INDICATES“Blocked Inlet”The control system has detected open contacts atthe Blocked Intake air pressure switch - inadequatesupply of intake (combustion) air.CHECK/REPAIR• If the water heater has been installed as a conventionalvent appliance - Ensure the intake airconnection screen is not clogged with debris.See Service Notes - Venting on page 7.• If water heater has been installed as a directvent appliance - check for restrictions, too manyequivalent feet, or too many elbows in the intakeair piping. Review venting installation section ofthe Instruction Manual that came with the waterheater - see Table 1 on page 7 in this manual.Ensure the vent/intake air piping has beeninstalled within manufacturers requirements.• If water heater has been installed as a directvent appliance - temporarily disconnect theintake air pipe at the blower connection on thewater heater - ensure the screen inside theintake air connection was removed duringinstallation. See the Service Notes for ventingon page 7.• Check all wiring between the Blocked Intake airpressure switch and the CCB’s J6 Socket (page36) pins 4 & 14. Perform close visual inspectionof the pins inside the plug and socket - ensureplugs and sockets are mating properly and providinggood contact. Repair/replace anythingworn or damaged.• Review the air pressure switch informationbeginning on page 18. Perform the pressureswitch test procedure for the Blocked Intake airpressure switch - see pages 21 through 23.Replace the Blocked Intake switch if defective.• Call the technical support phone number shownon the water heater labeling for further assistanceif the problem has not been correctedafter performing the procedures outlined here.Technical Literature Department 46 of 52 Ashland City, TN © 2008Servicing should only be performed by a Qualified Service Agent