SERVICE HANDBOOK

ULTRA HIGH EFFICIENCY POWER VENT/POWER DIRECT VENT - SERVICE MANUALFAULT MESSAGES (CONT)DISPLAYED MESSAGECONDITION/INDICATES“Blocked Exhaust Vent”The control system has detected open contacts atthe Blocked Exhaust air pressure switch - the waterheater is not venting properly.“Blower Prover Failure”The control system has detected closed contacts atthe Blower Prover air pressure switch out ofsequence. Blower Prover air pressure switchcontacts should be open at the beginning of eachheating cycle - see the Sequence of Operation onpage 40.CHECK/REPAIR• Check for restrictions, too many equivalent feet,or too many elbows in the vent pipe. Ensure• Review venting installation section of theInstruction 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.• Check all wiring between the Blocked Exhaustair pressure switch and the CCB’s J6 Socket(page 36) pins 5 & 10. Perform close visualinspection of the pins inside the plug and socket- ensure plugs and sockets are mating properlyand providing good contact. Repair/replace anythingworn or damaged.• Review the air pressure switch informationbeginning on page 18. Perform the pressureswitch test procedure for the Blocked Exhaustair pressure switch - see pages 21 through 23.Replace the Blocked Exhaust 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.• Check all wiring between the Blower Prover airpressure switch and the CCB’s J6 Socket (page36) pins 6 & 7. Ensure there are no shorted orpinched wires.• Ensure there are no jumper wires installed onthe Blower Prover switch.• Ensure there are no jumper wires installedbetween the CCB’s J6 Socket pins 6 & 7.• Review the air pressure switch informationbeginning on page 18. Perform the pressureswitch test procedure for the Blower Prover airpressure switch - see pages 21 through 23.Replace the Blower Prover 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 47 of 52 Ashland City, TN © 2008Servicing should only be performed by a Qualified Service Agent