resideo S8910U3000 Manuel D'installation page 20

S8910U3000
START
TURN THERMOSTAT TO
CALL FOR HEAT
DOES S8910U GET POWER
(24 VAC NOMINAL)?
YES
30 SECOND MINIMUM
PURGE
YES
IGNITER WARMS UP AND
GLOWS RED
YES
MAIN BURNER LIGHTS
YES
MAIN BURNER REMAINS
POWERED AND LIT
YES
SYSTEM RUNS UNTIL CALL
FOR HEAT ENDS
YES
CALL FOR HEAT ENDS,
SYSTEM SHUTS OFF
YES
TROUBLESHOOTING ENDS
34-00008EFS—03
NOTE: BEFORE TROUBLESHOOTING, BECOME FAMILIAR WITH STARTUP
AND CHECKOUT PROCEDURES.
NO
• CHECK LINE VOLTAGE POWER.
• CHECK LOW VOLTAGE TRANSFORMER.
• CHECK LIMIT CONTROLLER.
• CHECK AIR PROVING SWITCH (IF USED).
• CHECK THERMOSTAT.
• CHECK WIRING.
NO
• CHECK AIR PROVING SWITCH.
• REPLACE S8910U.
NO
CONFIRM THAT 120V HOT LEAD
CONNECTS TO L1, AND 120V NEUTRAL
LEAD CONNECTS TO L2.
YES
CHECK FOR 120 VAC ACROSS HOT
SURFACE IGNITER TERMINALS.
YES
CHECK WIRES TO IGNITER.
IF OK, REPLACE IGNITER.
NO
• CHECK FOR 24 VAC ACROSS VALVE TERMINALS ON S8910U DURING TRIAL FOR IGNITION
TIMING. IF NO VOLTAGE, REPLACE S8910U.
• CHECK ELECTRICAL CONNECTIONS BETWEEN S8910U AND GAS CONTROL.
IF OK, REPLACE GAS CONTROL.
• CHECK IGNITER POSITION.
• CHECK GAS PRESSURE TO MAIN BURNER.
NOTE: IF S8910U GOES INTO LOCKOUT, RESET SYSTEM.
NO
• CHECK CONTINUITY OF GROUND WIRE AND GROUND PATH FROM MAIN BURNER TO
GND (BURNER) TERMINAL OF S8910U.
• CONFIRM THAT 120 VAC HOT LEAD IS CONNECTED TO L1 AND 120 VAC NEUTRAL LEAD
IS CONNECTED TO L2.
• CHECK THAT BURNER FLAME COVERS IGNITER/SENSOR OR SENSOR.
• CHECK INSULATION ON IGNITER/SENSOR LEADS.
• CHECK IGNITER/SENSOR OR FLAME ROD FOR CONTAMINATION OR DAMAGE. REPLACE,
IF NECESSARY.
• CHECK INSULATION ON SENSOR LEADS AND CHECK SENSOR POSITION.
IF CHECKS ARE OK, REPLACE S8910U MODULE.
NOTE: SYSTEM FAILURE AFTER MAIN FLAME LIGHTS HAS A LOW PROBABILITY
OF BEING THE S8910U.
NOTE: IF S8910U GOES INTO LOCKOUT, RESET SYSTEM.
NO
• CHECK CONTINUITY OF GROUND WIRE.
NOTE: IF GROUND IS POOR OR ERRATIC, SHUTDOWNS CAN OCCUR OCCASIONALLY
EVEN THOUGH OPERATION IS NORMAL AT THE TIME OF CHECKOUT.
• CHECK FOR EXCESSIVE HEAT AT IGNITER OR FLAME ROD CERAMIC BASE
(TEMPERATURE ABOVE 1000F (538C) CAUSES SHORT TO GROUND).
• IF CHECKS ARE OKAY, REPLACE S8910U MODULE.
NOTE: SYSTEM FAILURE DURING A RUN CYCLE HAS A LOW PROBABILITY OF
BEING THE S8910U.
NO
• CHECK FOR PROPER TEMPERATURE CONTROLLER OPERATION.
• REMOVE VALVE LEAD AT S8910U; IF VALVE CLOSES, RECHECK TEMPERATURE CONTROLLER
AND WIRING; IF NOT, REPLACE GAS CONTROL.
REPEAT PROCEDURE UNTIL TROUBLE-FREE OPERATION IS OBTAINED.
Fig. 7. S8910U troubleshooting sequence.
20
NO
CHECK AND CORRECT WIRING FUSE
OR CIRCUIT BREAKER.
NO
REPLACE S8910U.
M8531B