GMEC96 Service Manual

SERVICING
41
Service Problem No Heat Unsatisfactory Heat
POSSIBLE CAUSE
DOTS IN ANALYSIS
GUIDE INDICATE
"POSSIBL E CAUSE"
SYMPTOM
Syst em Will Not Sta rt
Burner Won't Ignite
Burner Ignites-Locks Out
Burner Shuts Off prior to T'Stat being Satisfied
Short Cy cles
Long Cycles
Soot and /or Fumes
Too Much Heat
Not Enough Heat
Test Method
Remedy
See Service Procedure Reference
Power Failure
•
Test Voltage
S-1
Blown Fuse
•
Test Voltage
S-4
Loose Connection
•
Check Wiring
S-2
Shorted or Broken Wires
•
Check Wiring
S- 3A
No L ow Vo lta ge
•
Check Transformer
S-4
Faulty Thermostat
•••••
Check Thermostat
S- 3A
Faulty Transformer
•
Check Transformer
S-4
Poor or High Resistance Ground
•
Measure Ground Resistance
S-17B
Improper Heat Anticipator Setting
•• • •
Adjust Heat Anticipator Setting
S-3 B
Improper Thermostat Location
•• • •
Relocate Thermostat
S- 316
Faulty Limit or Roll Out Switch
••
Test Control
S-300 / S-302
Faulty Flame Sensor
•
Test Flame Sensor
S- 314
Faulty Ignition Control
•••
Test Control
S- 313
Gas Valve or Gas Supply Shut Off
•
Turn Valves to On Position
S- 317
Faulty Induced Draft Blower
••
Test Induced Draft Motor
S- 303
Faulty Blower Motor (PSC)
••
Test Blower Motor (PSC)
S-16A,B,C
Broken or Shorted Ignitor
•
Test Ignitor
S- 308
Dirty Flame Sensor, Low UA
•
Clean Flame Sensor
S- 314
Stuck Gas Valve
•••
Replace Gas Valve
S- 304
Fa ult y Gas Val ve
•••
Replace Gas Valve
S- 304
Open Auxiliary Limit
••
Reset Control
S- 301
Improper Air Flow or Distribution
••
Check Duct Static
S- 200
Cycling on Li mit
•• •
Check Controls & Temperature Rise
S-201 / S-300
Delayed Ignition
•
Test for Delayed Ignition
S- 312
Fl ashback
•
Test for Flashback
S-309 / S-311
Orifice Si ze
•• •
Check Orifices
S-306 / S-311
Gas Pressure
••••
Check Gas Pressure
S- 307
Cracked Heat Exchanger
•
Check Burner Flames
S- 305
Furnace Undersized
••
Replace with Proper Size Furnace
S- 318
Furnace Oversized
•
Replace with Proper Size Furnace
S- 318
Faulty Pressure Switch
•••
Test Pressure Switch
S- 310
Blocked or Restricted Flue
•
Check Flue/Drawdown Pressure
S- 310
Open Roll Ou t Switch
••
Test Flame Roll Out Control
S- 302
Bouncing On Pressure Switch
•
Test Negative Pressure
S- 310