Troubleshooting Guide: Heater - Schwank SET - SETU Owner's Manual

22. TROUBLESHOOTING GUIDE - HEATER OPERATION
WARNING
SEQUENCE OF EVENTS (also see DSI Troubleshooting previous page)
APPLY 120 VOLTS
SET THERMOSTAT TO CALL FOR HEAT
COMBUSTION AIR BLOWER STARTS
YES
AIR PROVING SWITCH HAS CLOSED 24
VOLTS IS PRESENT AT "PSW"
CONTROL.
YES
BLOCKED FLUE SWITCH IS CLOSED
24 VOLTS IS PRESENT AT "TH" AT DSI
CONTROL.
YES
SPARK IGNITER / SENSOR
YES
24V TO GAS VALVE
CONTINUED
Improper adjustment, alteration, service or maintenance can
cause property damage, injury or death. This heater must be
NO  REMEDY 120 VOLTS SUPPLY FAULT
 CHECK 120V TO DSI AT "L1"
NO
 CHECK 120V OUT AT "IND" FROM DSI TO BLOWER
NO
 FAULTY RELAY SWITCH IN DSI — REPLACE DSI
 CHECK TUBING TO SWITCH IS CONNECTED AND
NO
AT DSI
 CHECK AIR PRESSURE WITH MANOMETER
 CHECK FOR OBSTRUCTION IN THE AIR INTAKE
 CHECK INTEGRITY OF SWITCH
 CHECK TUBING TO SWITCH IS CONNECTED AND
NO
 CHECK AIR PRESSURE WITH MANOMETER
 CHECK INTEGRITY OF SWITCH
 CHECK FOR AND REMEDY ANY OBSTRUCTION IN
 CHECK DSI CONTROL FUSE FOR CONTINUITY
NO
 VISIBLY CHECK IF IGNITER IS SHORTING OUT
 CHECK GROUND WIRING
 REMOVE AND INSPECT IGNITER AND LEAD
 CHECK BOOT OF THE IGNITION CABLE FOR SIGNS
 IF "YES" ... TAKE PROTECTIVE ACTION TO SHIELD
 CHECK CERAMIC INSULATOR AND CAP
 CHECK SPARK GAP SETTING IS 3/16" (ADJUST BY
 PERFORM IGNITION LEAD TEST (See SPARK IGNI-
 GOOD SPARK.....REPLACE IGNITER
 NO SPARK/OR WEAK.....REPLACE CONTROL
37
NOT BLOCKED OR KINKED
 REPLACE DEFECTIVE BLOWER
 REPLACE DEFECTIVE SWITCH
NOT BLOCKED OR KINKED
 REPLACE DEFECTIVE SWITCH
THE VENT / TUBE
OF MELTING OR OVERHEATING
CABLE AND BOOT FROM EXCESSIVE TEMPERA-
TURE; REPLACE ANY DEFECTIVE COMPONENT
MOVING THE GROUND PRONG ONLY)
TION CIRCUIT INSTRUCTIONS—Section 22)
SET(U)-F / ITT(U)-F Manual
IM091221
RD: FEB 2014
RL: 8B