GMEC96 Service Manual

SERVICING
45
Service Problem No Heat Unsatisfactory Heat
POSSIBLE CAUSE
DOTS IN ANALYSIS
GUIDE INDICATE
"POSSI BLE CAUSE"
SYMPTOM
System Will Not Start
Burner Won't Ignite
Burner Ignites-Locks Out
Burner Shuts Off prior to T'Stat being Satisfied
Short Cycles
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 Fu se
•
Test Voltage
S-4
Loo se Co nnection
•
Check Wiring
S-2
Shorted or Broken Wires
•
Check Wiring
S- 3A
No L ow Vo lta ge
•
Check Transfor mer
S-4
Faulty Th ermostat
•••••
Check Thermostat
S- 3A
Fa ulty Transformer
•
Check Transfor mer
S-4
Poor or High Resistance Ground
•
Measure Ground Resistance
S-17B
Improper Heat Anticipator Setting
•• • •
Adjust Heat Anticipator Setting
S-3B
Improper Thermostat Location
•• • •
Relocate Thermostat
S- 316
Faulty Limit or Roll Out Switch
••
Test Control
S-300 / S-302
Fa ulty Fla me Sensor
•
Test Flame Sensor
S- 314
Faulty Ignition Control
•••
Test Control
S- 313
Gas Va lve or Gas Supp ly Shut Off
•
Turn Valves to On Position
S- 317
Faulty Induced Draft Blower
••
Test Induced Draft Motor
S- 303
Fa ulty Blower Motor (PSC)
••
Test B lower 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 Ga s Valve
S- 304
Fa ult y G as Val ve
•••
Replace Ga s Valve
S- 304
Ope n Auxil iary 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 Pressu re
••••
Check Gas Pressure
S- 307
Cr acked 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
Ope n Roll Ou t S witch
••
Test Flame Roll Out Control
S- 302
Bouncing On Pressure Switch
•
Test Ne gative Pr essure
S- 310