69-0845—2
16
S8910U UNIVERSAL HOT SURFACE IGNITION MODULE
Home and Building Control
Honeywell Limited-Honeywell Limitée
155 Gordon Baker Road
North York, Ontario
M2H 2C9
Helping You Control Your World
69-0845—2 J. S. Rev. 7-96 Printed in U.S.A
Home and Building Control
Honeywell Inc.
Honeywell Plaza
P.O. Box 524
Minneapolis, MN 55408-0524
CONFIRM THAT 120V HOT LEAD
CONNECTS TO L1, AND 120V NEUTRAL
LEAD CONNECTS TO L2.
M8531A
NO
NO
NO
NO
NO
NO
YES
YES
NO
NO
NO
YES
YES
YES
YES
YES
YES
YES
START
TURN THERMOSTAT TO
CALL FOR HEAT
DOES S8910U GET POWER
(24 VAC NOMINAL)?
30 SECOND MINIMUM
PURGE
IGNITER WARMS UP AND
GLOWS RED
REPEAT PROCEDURE UNTIL TROUBLE-FREE OPERATION IS OBTAINED.
SYSTEM RUNS UNTIL CALL
FOR HEAT ENDS
CALL FOR HEAT ENDS,
SYSTEM SHUTS OFF
TROUBLESHOOTING ENDS
•
•
CHECK FOR PROPER TEMPERATURE CONTROLLER OPERATION.
REMOVE VALVE LEAD AT S8910U; IF VALVE CLOSES, RECHECK TEMPERATURE CONTROLLER
AND WIRING; IF NOT, REPLACE GAS CONTROL.
NOTE: IF S8910U GOES INTO LOCKOUT, RESET SYSTEM.
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 1000
°
F (538
°
C) 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.
•
•
•
MAIN BURNER REMAINS
POWERED AND LIT
MAIN BURNER LIGHTS
CHECK FOR 120 VAC ACROSS HOT
SURFACE IGNITER TERMINALS.
NOTE: IF S8910U GOES INTO LOCKOUT, RESET SYSTEM.
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.
•
•
•
•
•
•
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.
•
•
•
•
REPLACE S8910U.
CHECK AND CORRECT WIRING FUSE
OR CIRCUIT BREAKER.
CHECK WIRES TO IGNITER.
IF OK, REPLACE IGNITER.
CHECK AIR PROVING SWITCH.
REPLACE S8910U.
•
•
CHECK LINE VOLTAGE POWER.
CHECK LOW VOLTAGE TRANSFORMER.
CHECK LIMIT CONTROLLER.
CHECK AIR PROVING SWITCH (IF USED).
CHECK THERMOSTAT.
CHECK WIRING.
•
•
•
•
•
•
NOTE: BEFORE TROUBLESHOOTING, BECOME FAMILIAR WITH STARTUP
AND CHECKOUT PROCEDURES.
Fig. 8. S8910U troubleshooting sequence.