26
TROUBLESHOOTING
Service Problem
No Heat
Unsatisfactory
Heat
POSSIBLE CAUSE
DOTS IN ANALYSIS
GUIDE INDICATE
"POSSIBLE CAUSE"
SYM
PT
O
M
Sy
ste
m
W
ill N
ot S
ta
rt
Bur
ner
W
on'
t I
gni
te
Bur
ner
Igni
tes
-Loc
ks
O
ut
Bur
ner
S
hut
s
O
ff
pr
ior
to
T'
St
at
bei
ng
Sat
is
fied
Shor
t C
yc
les
Long
C
yc
les
Soot
and
/or
F
um
es
Too
M
uc
h
H
eat
N
ot
E
nough
H
eat
Test Method
Remedy
See
Ser
vi
ce
Pr
oced
ur
e
Ref
er
en
ce
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-3A
No Low Voltage
•
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-3B
Improper Thermostat Location
• •
• •
Relocate Thermostat
S-316
Faulty Limit or Roll Out Sw itch
•
•
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 Blow er
•
•
Test Induced Draft Motor
S-303
Faulty Blow er Motor (PSC)
•
•
Test Blow er 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
Faulty Gas Valve
•
•
•
Replace Gas Valve
S-304
Open Auxiliary Limit
•
•
Reset Control
S-301
Improper Air Flow or Distribution
•
•
Check Duct Static
S-200
Cycling on Limit
• •
•
Check Controls & Temperature Rise
S-201 / S-300
Delayed Ignition
•
Test for Delayed Ignition
S-312
Flashback
•
Test for Flashback
S-309 / S-311
Orifice Size
• • •
Check Orifices
S-306 / S-311
Gas Pressure
•
• • •
Check Gas Pressure
S-307
Cracked Heat Exchanger
•
Check Burner Flames
S-305
Furnace Undersized
•
•
Replace w ith Proper Size Furnace
S-318
Furnace Oversized
•
Replace w ith Proper Size Furnace
S-318
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 Flame Roll Out Control
S-302
Bouncing On Pressure Sw itch
•
Test Negative Pressure
S-310
