Blocked Exhaust - A.O. Smith BTH 120 Service Handbook

6. BLOCKED EXHAUST

Blocked Exhaust
Fault occurred 2 mins ago
Restriction in exhaust pipe. Check
exhaust pipe and termination for
blockage.
Call a service professional:
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CHANGE
CHECK/ REPAIR:
• Check pipe for restriction or excessive equivalent length.
• See Instruction Manual for pipe size, length and maximum number of elbows.
• Check actual pipe pressure with a manometer during blower operation. See "Pressure Switch Tests" section
on Page 12 thru Page 15 under "Blower Operation Error" on Page 11.
BACK ADVANCED
Servicing should only be performed by a Qualified Service Technician
CAUSES:
• The Blocked Exhaust Switch has detected a
possible restriction in the exhaust pipe.
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