Service manual

SERVICING
26
Complaint No Heat Unsatisfactory Heat
POSSIBLE CAUSE
DOTS IN ANALYSIS
GUIDE INDICATE
"POSSIBLE CAUSE"
SYMPTOM
System Will Not Start Burner Won't Ignite Burner Ignites-Locks Out Burner Shuts Off prior to T'Stat being Satasfied Short Cycles Long Cycles Soot and /or Fumes To Much Heat Not Enough Heat
Test Method
Remedy
See Service Procedure Reference
Power Failure
•
Test Volta
g
e S-1
Blown Fuse
•
Test Volta
g
e S-4
Loose Connection
•
Check Wirin
g
S-2
Shorted or Broken Wires
•
Check Wirin
g
S-3
No Low Volta
g
e
•
Check Transformer S-4
Faulty Thermostat
• • • •
Check Thermostat S-3
Faulty Transformer
•
Check Transformer S-4
Poor or Hi
g
h Resistance Ground
•
Measure Ground Resistance S-313
Improper Heat Anticipator Settin
g
• • • •
Adjust Heat Anticipator Settin
g
S-3
Improper Thermostat Location
• • • •
Relocate Thermostat
Faulty Limit or Roll Out Switch
• •
Test Control S-300-302
Faulty Flame Sensor
•
Test Flame Sensor S-314
Faulty I
g
nition Control
• •
Test Control S-313
Gas Valve or Gas Supply Shut Off
•
Turn Valves to On Position S-304
Faulty Induced Draft Blower
• •
Test Blower S-309
Broken or Shorted I
g
nitor
•
Test I
g
nitor S-312
Faulty Combustion Relay
• •
Test Relay S-20
Dirty Flame Sensor, Low uA
•
Clean Flame Sensor S-314
Flame Sensor not in Flame, Low uA
•
Test/Adjust Position of Flame Sensor S-314
Faulty Gas Valve
• • •
Replace Gas Valve S-304
Open Auxillary Limit
• •
Reset Control S-301
Improper Air Flow or Distribution
• •
Check Duct Static
Cyclin
g
on Limit
• • •
Check Controls & Temperature Rise S-300
Delayed I
g
nition
•
Test for Delayed I
g
nition S-308
Flashback
•
Test for Flashback S-309
Orifice Size
• • •
Check Orifices S-306
Gas Pressure
• • • •
Check Gas Pressure S-307
Cracked Heat Exchan
g
er
•
Check Burner Flames S-302
Stuck Gas Valve
• • •
Replace Gas Valve S-304
Furnace Undersized
•
Replace with Proper Size Furnce
Faulty Pressure Switch
• • •
Test Pressure Switch S-310
Blocked or Restricted Flue
•
Check Flue/Drawdown Pressure S-310
Open Roll Out Switch
• •
Test Control S-302
Collector Box "J" Tube Position
• •
Test Ne
g
ative Pressure S-310
Bouncin
g
On Pressure Switch
•
Test Ne
g
ative Pressure S-310
GAS HEATING - SERVICE ANALYSIS GUIDE