Troubleshooting - Schwank STV-JZ Owner's Manual

21. TROUBLESHOOTING GUIDE HONEYWELL S87J1034 CONTROL
SET THERMOSTAT TO CALL FOR HEAT
RELAY IS CLOSED
VACUUM PUMP MOTOR STARTS
TRANSFORMER IS POWERED AND
GREEN L.E.D. LIGHT IS ON
YES
AIR PROVING SWITCH CLOSED
24 VOLTS AT IGNITION CONTROL
AMBER L.E.D. LIGHT IS ON
YES
SPARK ACROSS IGNITER OR
IGNITER/SENSOR GAP
YES
cont'd
NO
→ENSURE THAT THE AIR INTAKE AND FLUE ARE NOT
BLOCKED
→ENSURE PRESSURE TUBE IS CONNECTED AND NOT
BLOCKED
→CHECK AIR PROVING SWITCH IS CLOSING WHEN
NO
BLOWER IS RUNNING
→CHECK AIR PRESSURE WITH MANOMETER
→REPLACE DEFECTIVE SWITCH
→SEE PAGE 24 SPARK IGNITION CIRCUIT
→PULL IGNITION LEAD AND CHECK SPARK
→CHECK SPARK GAP, ADJUST TO 3/16" IF NEEDED
BY MOVING THE GROUND PRONG ONLY
NO
→SPARK OK?
Page 25
120 volt Thermostat:
Leaving the Jumper in
across the red and
white terminal block
wires in Burner housing
energizes the switching
relay to power 120v to
the Vacuum pump.
CHECK FOR LINE VOLTAGE POWER SUPPLY
CHECK WIRING CONNECTION AND
REPLACE BLOWER MOTOR IF DEFECTIVE
NO
YES
REPLACE IGNITION CONTROL
→CHECK IGNITION CABLE, GROUND WIRING
CERAMIC INSULATOR AND C A P, A N D
CORRECT
→CHECK BOOT OF THE IGNITION CABLE FOR
SIGNS OF MELTING OR BUCKLING
→TAKE PROTECTIVE ACTION TO SHIELD
CABLE AND BOOT FROM EXCESSIVE
TEMPERATURES
24 volt Thermostat:
Remove jumper across
the red and white wires
at terminal block in
Burner housing. Wire in
a 24v Thermostat in its
place to switch the relay
and power the Vacuum
pump.
GP-MSJV-BX-07A
STV-JZ Manual
RD: MAR 2009
RL: 07A - BA