Form RZ-NA-I-FT, Mfg No. 173473 Rev 8, Page 19
33. Troubleshooting
Circuit Board LED Codes
Slow Flash ..... Normal Operation, No call for heat
Fast Flash ....... Normal Operation, Call for heat
2 Flashes ........ System Lockout, Failed to detect or sustain flame
3 Flashes ........ Pressure Switch Open or Closed
4 Flashes ........ High Limit or Flame Rollout Switch Open
5 Flashes ........ Flame Sensed and Gas Valve not energized
Steady On ...... Internal Failure - Replace the circuit board
Check the Circuit Board
- The integrated circuit
board monitors the operation of the heater and in-
cludes an LED signal that indicates normal opera-
tion and various abnormal conditions. If the heater
fails to operate properly, check this signal to deter-
mine the cause and/or to eliminate certain causes.
Do not attempt to repair the integrated circuit
board
; it does not have any field replaceable com-
ponents.
PROBLEM
PROBABLE CAUS E
REMEDY
Venter motor
1.
No p ower to unit.
1.
Turn on p ower, check supp ly fuses or circuit breaker.
will not start
2.
No 24 volt power to venter relay.
2.
Turn up thermostat; check control transformer outp ut.
3.
Integrated circuit board defective.
3.
Rep lace integrated circuit board.
4.
Defective motor.
4.
Rep lace motor.
Burners will
1.
M anual valve not op en.
1.
Op en manual valve.
not light
2.
Air in the gas line.
2.
Bleed gas line.
3.
Gas pressure too high or too low.
3.
Correct supp ly p ressure is 5" - 14" w.c. for natural gas or 11" - 14"
w.c. for p ropane gas.
4.
No Spark:
4.
a) Loose wire connections
a) Be certain all wire connections are solid.
b) Transformer failure
b) Be sure 24 volts is available.
c) Incorrect sp ark gap.
c) M aintain spark gap at 1/8".
d) Spark cable shorted to ground.
d) Replace worn or grounded sp ark cable.
e) Sp ark electrode shorted to ground
e) Rep lace if ceramic spark electrode is cracked or grounded.
f) Burners not grounded
f) M ake certain integrated circuit board is grounded to ignitor.
g) Circuit board not grounded.
g) M ake certain integrated circuit board is grounded to furnace chassis.
h) Faulty integrated circuit board
h) If 24 volt is available to the integrated circuit board and all other causes
have been eliminated, rep lace board.
5.
Lockout device interrupting control
circuit by above causes.
5.
Reset lockout by interrup ting control at the thermostat or main power.
6.
Faulty combustion air proving switch.
6.
Rep lace combustion air proving switch.
7.
M ain valve not operating.
7.
a) Defective valve
a) If 24 volt is measured at the valve connections and valve remains
closed, replace valve.
b) Loose wire connections
b) Check and tighten all wiring connections.
8.
Integrated circuit board does not power
main valve.
8.
a) Loose wire connections
a) Check and tighten all wiring connections.
b) Flame sensor grounded
b) Be certain flame sensor lead is not grounded or insulation or ceramic is
not cracked. Replace as required.
c) Incorrect gas pressure
c) Correct supp ly p ressure is 5" - 14" w.c. for natural gas or 11" - 14"
w.c. for p ropane gas.
d) Cracked ceramic at sensor
d) Replace sensor
1.
Gas pressure too high or too low.
1.
Correct supp ly p ressure is 5" - 14" w.c. for natural gas or 11" - 14"
w.c. for p ropane gas.
2.
Burners not grounded
2.
M ake certain integrated circuit board is grounded to ignitor.
3.
Circuit board not grounded.
3.
M ake certain integrated circuit board is grounded to furnace chassis.
4.
Faulty integrated circuit board
4
. If 24 volt is available to the integrated circuit board and all other causes
have been eliminated, rep lace board.
5.
Faulty combustion air proving switch.
5.
Rep lace combustion air proving switch.
6.
Flame sensor grounded
6.
Be certain flame sensor lead is not grounded or insulation or ceramic is
not cracked. Replace as required.
7.
Cracked ceramic at sensor
7
. Rep lace sensor
8.
Incorrect polarity
8
. Reverse 115V line connections at ignition control module.
Burners cycle on
and off
