Reznor, RHC21 4000 Installation EN May 2021 D301334 Issue 0 Page No 45 of 56
8. Fault finding
START
Ensure gas & electricity
supplies are enabled.
Turn external controls to
call for heat.
Does the LED status
light illuminate?
NO
YES
NO
YES
CHECK: -
1. Operation of any external timer, thermostat or control.
2. External circuit breaker or fuse.
3. Voltage is correct – see technical data table.
4. Integrity of supply circuit.
Is there power to the
burner?
CHECK:
-
1. Voltage is correct – see technical data table.
2. Ignition controller fuse.
3. Integrity of wiring connections.
4. Lockout reset circuit board
5. LED lamp.
6. Ignition controller.
Does the combustion
fan run?
NO
YES
CHECK: -
1. Voltage supply to fan terminals is 230VAC / 50Hz.
2. Integrity of wiring connections.
3. Fan, including the free movement of the fan wheel.
Does the burner
ignite after a purge
period?
NO
Is there power to the
fan?
YES
NO
CHECK: -
1. Integrity of wiring connections.
2. Heat demand signal is > 0.95VDC.
3. OT terminals are linked or OpenTherm compatible thermostat connected
with heat demand.
4. Ignition controller.
5. LED status light flash codes.
Does the burner spark?
YES
NO
CHECK: -
1. Gas supply turned on / purged.
2. Supply pressure.
3. Voltage supply to gas valve plug 230VAC / 50Hz during ignition.
4. Ignition controller.
5. Throttle positioning – see commissioning data table.
6. Correct program key fitted.
7. Gas valve.
8. Integrity of appliance ground connection.
9. Probe leads connected / integrity.
10. Flame sensor probe clean.
11. Probes not touching insulation.
12. Flame signal (min. 1.0µA).
13. Air inlet / flue pipe for obstructions.
CHECK: -
1. Spark gap correct – see maintenance section.
2. Check ignition probes / leads for damage.
3. Spark probe not touching insulation.
4. Voltage supply to ignition transformer 230VAC /
50Hz during ignition.
4. Ignition transformer.
5. Ignition controller.
YES
Does the
burner stay on
after stabilisation
time?
NO
YES
CHECK: -
1. Heat demand still present.
2. Gas supply purged.
3. Supply pressure.
4. Throttle positioning – see commissioning data table.
5. Flame sensor probe corroded.
6. Flame signal (min. 1.0µA).
7. Flame sensor probe bent.
8. Integrity of appliance ground connection.
9. Probe leads connected / integrity.
10. Ignition controller.
11. Integrity of chamber insulation.
Page 2
Does the lockout
light illuminate?
YES
YES
NO
CHECK:
-
1. LED status light flash codes.
2. LC3 safety thermostat reset switch.
3. LC1 safety thermostat (10k resistance).
4. Lockout reset circuit board.
5. Ignition controller.
6. Flame sense probe.
7. Integrity of wiring connections.
Does the
lockout light go
off after
pressing switch
for 3 seconds?
NO
NOTE: presence
of a flame is
indicated by
the green lamp
illuminating.
NOTE: presence
of a flame is
indicated by
the green lamp
illuminating.
