Troubleshooting Chart
FOR MODELS: 3508731; 3508732; 5008731; 5008732; 6508731; 6508732
SYMPTOM
3. Burner comes "ON" but
goesOFF before blower
turns ON. (cont.)
POSSIBLE CAUSE(S)
c, Defectivemotor(2-speed).
d. Defective motor (1-speed).
e. Defective fan switch.
a. Furnace not operating at full
rate.
a. Furnace operating over-rate.
b. Line voltage too low.
c. Recirculation.
*4. Burnercomes "ON", blowe
comes "ON", but cycles
"ON" and "OFF" while
burner remains "ON".
*5. Burner comes "ON",
blower comes "ON", but
burner cycles "OFF" and
"ON" with blower "ON".
"6. Furnace operates but turns
"OFF" before room tem-
perature is attained.
*7. Furnace operatesbut will not
shut "OFF" when room
temperature is attained.
*8. Abnormal operation.
d. Loss of circulating air due to
leakage.
a. Thermostat location.
b. Defective thermostat.
a. Thermostat wiring defective.
b. Thermostat location,
c Improper thermostat anticipator
setting.
a. Blower noise.
b. Expansion noise ticking,
c. Burnerresonance.
d. Seleclor switch defective.
(2-speed).
C.
d.
e.
a.
a.
b.
C,
d,
a.
b.
a.
b.
C.
CORRECTIVE ACTION
Jumperacross fan switch,turnelectric powerON, motor should
rotate.A2-speedmotor is used-- jumper from "brown" terminal
onfanswitchto #2(red)terminalonselectorswitch, motorshould
rotateon"LOW" speed. Jumperfrom same"brown" terminalon
fan switchto#3 (black) terminalonselectorswitch, motorshould
rotateon "HIGH" speed. Replacemotor if defective.
Jumper across fan switch, turn electric power ON, motor should
rotate. Replace motor if defective.
If, after checkingabove possibilities, problem still exists, replace
fan switch.
Check for low gas pressure atgas valve -- should be 4" W.C.for
Natural Gas, 11" W.C. for L.R Gas. Check burner orifice.
Check for high gaspressure at gas valve-- correctif necessary.
See correct pressure above.
Check line voltage to motor, if below 115volts motor will run too
s_ow.
Heated air discharging against an object causing recirculation,
such as a hall installation or a large piece of furniture within 4'
of discharge.
Checkheaderplate installation and proper use ofgaskets.Repair
as necessary.
Checklocation of thermostat. It should not be in the path ofwarm
air discharge from furnace, near a lamp,or above a TV set or
stereo.
Check thermostatcalibration or replace.
Check thermostat wiringfrom furnace to thermostat -- may be
shorted together by a nail or staple.
Check thermostat location -- if an outside wall or a hole in wall
behind thermostatcausingcold air tocontactthermostat, relocate.
Set anticipator per THERMOSTATANTICIPATOR,page 20.
Check motor mounts -- they may be loose. Blower wheelcould
be out ofbalance Setscrew may be looseon motor shaft. Blower
may be rubbing on fan shroud. Motor may need oiling. Correct
as needed.
Check installation -- casing may be twisted or not level at time
of installation causing combustion chamber to bind on its locating
pros
Usually associated with L.R Gas operation. Adjust primary air
screw =nthroatof each cast iron burner after about 10 minutes
of operation. Adjust to obtain a soft blue flame without streaming
yellow tips,
During normal furnace operation motor will be on "LOW" speed
when operatingon minimum inputcapacity and on"HIGH" speed
whenoperating on maximum input capacity. Ifthere is no change
in motor speed, replace selector switch.
"Also applicableto Models with an electric intermittent pilotsystem.
--34--
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