Pilot Model - Atwood 79 Series Service Manual

Guides are only intended for use on Atwood
Atwood training. This guide should be used in conjunction with the appropriate Instruction Manual provided with the
®
product and any applicable Industry Standards. This is not intended to be a complete list. Please direct questions
concerning service of Atwood
CAUSE
BURNER FAILS TO IGNITE AND - BLOWER FAILS TO RUN
No electrical power to the furnace
Current overload protector device
Thermostat defective
Thermostat wires broken
Thermostat located in high area
Blower motor defective
Blower relay defective
Wire off motor
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Wire off relay
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Improper ground
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BLOWER RUNS - BUT FAILS TO IGNITE
Low Voltage/High Voltage
12 volt polarity reversed
Furnace grounding wires not secure
Gas valve defective
Gas pressure incorrect
Limit switch defective or wire off
Sail switch defective or wire off
Burner orifice blocked
Combustion air wheel loose
Burner head adjustment
Exhaust blocked
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Air intake restricted
Broken or loose wire
Motor running slow
Pilot orifice plugged
Thermocouple defective
Pilot assembly defective
BURNER CYCLING ON AND OFF - BLOWER RUNS CONTINUOUSLY WITH THERMOSTAT "ON"
Restricted return air supply
Restricted discharge duct system
Defective limit switch
Furnace over fired
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® products by service technicians who have successfully completed
® products to 800-825-4328 option 5 before proceeding.
Reconnect or replace power source.*
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Reset circuit breaker. Check amp draw from motor defective or
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tripped (circuit breaker).according to furnace's specifications.
Replace thermostat.
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Replace wire or wires.
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Relocate thermostat.
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Replace motor.
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Replace relay.
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Reconnect wire.*
Reconnect wire.*
Clean and secure grounds.*
Correct power supply.*
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Correct polarity.*
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Clean and secure grounds established*
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Replace valve or valve coil, depending on problem encountered.
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*Set pressure to a minimum of 11˝ W.C. with all appliances running.
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(Replace regulator if not obtainable).
Reconnect wire or replace.
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Reconnect wire or replace.
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Clean main burner orifice or replace.
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Reposition and tighten.
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Reposition and tighten. Adjust burner according to furnace
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specifications.
Clean exhaust.*
Clean air intake.*
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Replace or tighten*
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Check voltage first. If 12 VDC while running, replace motor.*
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Clean or replace orifice
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Replace thermocouple
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Replace pilot assembly
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Make sure return air meets furnace's minimum requirements.
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a. Make sure ducting meets furnace's minimum requirements.*
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b. Make sure there is no excess ducting or unnecessary bends.*
c. Make sure any closeable registers are fully open and unrestricted.
Replace limit switch.*
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Set gas pressure to a minimum of 11˝ WC with all appliances
running. Replace regulator if not obtainable. Also, check main burner
orifice, it must comply with furnace's specifications.
*indicates NOT covered under warranty.
FURNACE - Pilot Model
TROUBLE SHOOTING GUIDE
SOLUTION
32
32
Effective: 8/10/98
continued backside