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Mfg P/N 98807 Rev 8, Page 27
42. Troubleshooting
TRO UB LE PRO B ABLE C AUS E REMEDY
Venter motor will
not start
1.
No power to unit.
1.
Turn on power, check supply fuses, or circuit breaker. If unit is equipped with
unit-mounted disconnect switch, check circuit breaker (See Paragraph 11).
2.
No 24 volt power to venter relay.
2.
Turn up thermostat; check control transformer output.
3.
Venter relay defective.
3.
Replace relay.
4.
Defective motor or capacitor.
4.
Replace motor or capacitor.
Pilot will not light 1.
Manual valve not open.
1.
Open manual valve.
(spark ignition 2.
Air in gas line.
2.
Bleed gas line.
system) 3.
Dirt in pilot orifice.
3.
Remove and clean with compressed air or solvent (do not ream).
4.
Gas pressure too high or too low.
4.
Adjust supply pressure. (See Paragraph 10).
5.
Kinked pilot tubing.
5.
Replace tubing.
6.
Pilot valve does not open.
6.
If 24 volt available at valve, replace valve.
7.
No spark:
7.
a)
Loose wire connections
a)
Be certain all wires connections are solid.
b)
Transformer failure.
b)
Be certain 24 volts is available.
c)
Incorrect spark gap.
c)
Maintain spark gap at .100".
d)
Spark cable shorted to ground.
d)
Replace worn or grounded spark cable.
e)
Spark electrode shorted to ground.
e)
Replace pilot if ceramic spark electrode is cracked or grounded.
f)
Drafts affecting pilot.
f)
Make sure all panels are in place and tightly secured to prevent drafts at pilot.
g)
Ignition control not grounded.
g)
Make certain ignition control is grounded to furnace chassis
h)
Faulty ignition controller.
h)
If 24 volt is available to ignition controller and all other causes have been
eliminated, replace ignition control.
8.
Optional lockout device interrupting control
circuit by above causes.
8.
Reset lockout by interrupting control at thermostat.
9.
Faulty combustion air proving switch.
9.
Replace combustion air proving switch.
Pilot lights, main 1.
Manual valve not open.
1.
Open manual valve.
valve will not open 2.
Main valve not operating.
2.
(Spark Ignition
system)
a)
Defective valve.
a)
If 24 volt is measured at valve connections and valve remains closed, replace
valve.
b)
Loose wire connections.
b)
Check and tighten all wiring connections.
3.
Ignition control does not power main valve.
3.
a)
Loose wire connections.
a)
Check and tighten all wiring connections.
b)
Flame sensor grounded. (Pilot lights - spark
continues)
b)
Be certain flame sensor lead is not grounded or insulation or ceramic is not
cracked. Replace as required.
c)
Gas pressure incorrect.
c)
Set supply pressure at 5" w.c. to 14" w.c. for natural gas and 11" w.c. to 14"
w.c. for propane gas.
d)
Cracked ceramic at sensor.
d)
Replace sensor.
e)
Faulty ignition controller.
e)
See Paragraph 33. If all checks indicate no other cause, replace ignition
controller. DO NOT ATTEMPT TO REPAIR IGNITION CONTROLLER.
THIS DEVICE HAS NO FIELD REPLACEABLE PARTS.
No heat (Heater 1.
Incorrect manifold pressure or orifices.
1.
Check manifold pressure (See Paragraph 10).
Operating) 2.
Cycling on limit control.
2.
Check air throughput (See Paragraph 15).
3.
Improper thermostat location or adjustment.
3.
See thermostat manufacturer's instructions.
Cold air delivered 1.
Fan control improperly wired
1.
Connect as per wiring diagram.
On Start-up 2.
Defective fan control.
2.
Replace fan control.
During Operation 3.
Incorrect manifold pressure.
3.
Check manifold line pressure (See Paragraph 10).
Motor will not run 1.
Circuit open.
1.
Check wiring and connections. .
2.
Fan control inoperative.
2.
Replace fan control.
3.
Defective motor or capacitor.
3.
Replace motor or capacitor.
Motor turns on 1.
Fan control improperly wired.
1.
Connect as per wiring diagram.
and off while 2.
Defective fan control.
2.
Replace fan control.
burner is operating
(See motor cuts out
3.
Poor contact between fan control and heat
exchanger tube. Surface contact is required.
3.
Check for bent mounting or loose mounting screws.
on overload 4.
Motor overload device cycling on and off.
4.
Check motor load against motor rating plate. Replace motor if needed.
below) 5.
Low ambient temperature (less than 40
o
F)
causing false cycling.
5.
Install fan delay relay kit (See Paragraph 17.)
Fan motor cuts 1.
Low or high voltage supply .
1.
Correct electric supply.
out on overload 2.
Defective motor.
2.
Replace motor.
3.
Poor air flow.
3.
Clean motor, fan and fan guard.
4.
Defective bearing or lubrication.
4.
Lubricate bearings or replace motor.
Blower motor 1.
Improper motor pulley and/or adjustment.
1.
See instructions in Paragraph 14.
cuts out on
2.
Improper static pressure in the duct system.
2.
Adjust duct system dampers.
overload 3.
Low voltage.
3.
Check power supply.