Troubleshooting Guide: Heater - Schwank UHE Installation & Owner's Manual

22. TROUBLESHOOTING GUIDE
WARNING
SEQUENCE OF EVENTS (also see DSI Troubleshooting previous page)
APPLY 120 VOLTS - GREEN LIGHT IS ON
SET THERMOSTAT TO CALL FOR HEAT
COMBUSTION AIR BLOWER STARTS
YES
AIR PROVING SWITCH HAS CLOSED 24
VOLTS IS PRESENT AT "PSW" AT DSI
CONTROL.
YES
BLOCKED FLUE SWITCH IS CLOSED
24 VOLTS IS PRESENT AT "TH" AT DSI
CONTROL.
AMBER LIGHT IS ON
YES
SPARK IGNITER / SENSOR
YES
24V TO GAS VALVE - RED LIGHT IS ON
CONTINUED
UHE-F / EIH-F I&O Manual
IM100205
RD: APR 2019
RL: 02C
Improper adjustment, alteration, service or maintenance can
cause property damage, injury or death. This heater must be
installed and serviced only by a trained gas service technician
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
NOT BLOCKED OR KINKED
• 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
NO
• CHECK DSI CONTROL FUSE FOR CONTINUITY
• VISIBLY CHECK IF IGNITER IS SHORTING OUT
• CHECK GROUND WIRING
• REMOVE AND INSPECT IGNITER AND LEAD
• CHECK BOOT OF THE IGNITION CABLE FOR SIGNS
OF MELTING OR OVERHEATING
• IF "YES" ... TAKE PROTECTIVE ACTION TO SHIELD
CABLE AND BOOT FROM EXCESSIVE TEMPERA-
TURE; REPLACE ANY DEFECTIVE COMPONENT
• CHECK CERAMIC INSULATOR AND CAP
• CHECK SPARK GAP SETTING IS 3/16" (ADJUST BY
MOVING THE GROUND PRONG ONLY)
• PERFORM IGNITION LEAD TEST (See SPARK IGNI-
TION CIRCUIT INSTRUCTIONS—Section 22)
• GOOD SPARK.....REPLACE IGNITER
• NO SPARK/OR WEAK.....REPLACE CONTROL
40
• REPLACE DEFECTIVE BLOWER
• REPLACE DEFECTIVE SWITCH
NOT BLOCKED OR KINKED
• REPLACE DEFECTIVE SWITCH
THE VENT / TUBE