A.O. Smith BTF-75 - Manual (Page 19)

19
SV9560/SV9570 SMARTVALVE ® WATER HEATER CONTROL
TROUBLESHOOTING GUIDE
START
l
CHECK FOR PROPER VOLTAGE AT
CONTROL HARNESS (SEE INSET A).
VOLTAGE SHOULD BE 120V
BETWEEN 120V COMMON AND
120V HOT.
TURN ON GAS SUPPLY PLUG
HARNESS INTO SmartValve
®
CONTROL. INITIATE A REQUEST
FOR HEAT. COMBUSTION BLOWER
SHOULD BE ON AND PREPURGED.
IGNITER WARMS UP AND
GLOWS RED.
MAIN VALVE OPENS AND MAIN
BURNER LIGHTS.
SYSTEM IS OKAY.
CHECK:
• LINE VOLTAGE POWER
• WIRING
WARNING
Line Voltage Hazard.
Can cause property damage,
severe injury or death.
Only a trained, experienced service
technician should perform this trouble-
shooting. Be certain to avoid contact
with pressure switch and/or electrical
connections.
CHECK:
• IS AIR PROOFING SWITCH STUCK
OR CLOSED.
• IS THE FLUE BLOCKED.
• IS THE WIRING CONNECTED
PROPERLY TO THE SWITCH AND
COMBUSTION BLOWER.
WITH IGNITER CABLE CONNECTED,
MEASURE VOLTAGE AT HSI ELEMENT
OUTPUT (SEE INSET B) 120V NOMINAL
CHECK DAMAGED OR BROKEN HSI
ELEMENT.
WARNING
Line Voltage Hazard.
Can cause property damage,
severe injury or death.
Only a trained, experienced service
technician should perform this trouble-
shooting. Be certain to avoid contact
with pressure switch and/or electrical
connections.
REPLACE HSI
CHECK:
• IS THE APPLIANCE EARTH GROUNDED
(120V BETWEEN HOT AND CHASSIS
GROUND).
• IS GAS SUPPLY OFF OR TOO LOW
PRESSURE TO OPERATE THE
CONTROL.
• DOES BURNER FLAME MAKE GOOD
CONTACT WITH THE FLAME ROD.
• IS FLAME SENSE ROD CONTAMINATED
OR IN AN INCORRECT LOCATION.
• IS THERE APPROXIMATELY 100 VAV
BETWEEN FLAME ROD AND BURNER
PAN WITH 120VAC INPUT TO
CONTROL.
• IF ALL OF THE ABOVE ARE GOOD,
REPLACE IGNITER AND FLAME ROD
ASSEMBLY.
CYCLE THERMOSTAT OFF AND BACK ON
MAIN BURNER LIGHTS REPLACE SmartValve ® CONTROL
NOTE: BEFORE TROUBLESHOOTING
BECOME FAMILIAR WITH THE STARTUP
AND CHECKOUT PROCEDURE.
REPLACE SmartValve ® CONTROL
WHEN MEASURING VOLTAGE
AT CONNECTIONS, USE CARE
TO ASSURE TERMINALS ARE
NOT DAMAGED.
1
1
1
NO
NO
NO
NO
NO
YES
YES
NO