Service Manual
SERVICING
33
GAS HEATING ANALYSIS CHART
Com plaint 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 Satasfi
e
Short Cycles
Long Cycles
Soot and /or Fumes
To Much Heat
Not Enough Heat
Test Method
Remedy
See Service Procedure Reference
Pow er Failure
•
Test Voltage S-1
Blow n Fuse
•
Test Voltage S-4
Loose Connection
•
Check Wiring S-2
Shorted or Broken Wires
•
Check Wiring S-3
No Low Voltage
•
Check Transformer S-4
Faulty Thermostat
••••
Check Thermostat S-3
Faulty Transformer
•
Check Transformer S-4
Poor or High Resistance Ground
•
Measure Ground Resistance S-313
Improper Heat Anticipator Setting
•• ••
Adjust Heat Anticipator Setting S-3
Improper Thermostat Location
•• ••
Relocate Thermostat
Faulty Limit or Roll Out Sw itch
•• •
Test Control S-300,S-301,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-304
Faulty Induced Draft Blow er
•• •
Test Blow er S-303
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
No High Stage Heat (2 Stage Only)
••
Check Thermostat, Control, Gas Valve S-3,S-313,S-304
Open Auxillary Limit
••
Reset Control S-301
Improper Air Flow or Distribution
••
Check Duct Static
Locking out on Main Limit
•• •
Check Controls, Gas Press., & Temp. Rise S-300
Delayed Ignition
•
Test for Delayed Ignition S-308
Flashback
•
Test for Flashback S-309
Orif ice Size
•••
Check Orifices S-306
Gas Pressure
• •••
Check Gas Pressure S-307
Cracked Heat Exchanger
•
Check Burner Flames S-302
Stuck Gas Valve
•••
Replace Gas Valve S-304
Furnace Undersized
•
Replace w ith Proper Size Furnace
Faulty Pressure Sw itch
•••
Test Pressure Sw itch S-310
Blocked or Restricted Flue
•
Check Flue/Draw dow n Pressure S-310
Open Roll Out Sw itch
••
Test Control S-302
Bouncing On Pressure Sw itch
••
Test Negative Pressure S-310