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Troubleshooting Without Status Indicator Assistance
Follow diagram in Fig. 6.
Thermopile Output Check
1. Turn device knob to OFF.
2. Disconnect thermopile leads.
3. Turn device knob to PILOT, hold down knob to light
pilot burner. Hold the knob down for five or more
minutes.
4. After five minutes, check thermopile output by
connecting the voltmeter to the positive red lead
and negative white lead.
5. Output should be at least 350 mV. (See Fig. 7.)
Connect the 3.6 ohm resistor between the two ther-
mopile leads, the voltage should be at or higher
than one half of the open circuit voltage.
6. The terminal housing prevents miswiring of positive
and negative leadwires.
7. Flame must envelop thermopile at Hot Junction (3/8
in. below tip).
8. Keep heat away from cold junction (brass sleeve of
the thermopile) for maximum output.
THERMOPILE OUTPUT WITH TIME
900
800
700
600
500
400
300
200
100
0
0
1
2
3
Fig. 7. Thermopile output.
TROUBLESHOOTING GUIDE WITHOUT STATUS LIGHT
TURN DEVICE KNOB FROM OFF TO
PILOT, PRESS DOWN KNOB AND HOLD,
LIGHT PILOT BY DEPRESSING PIEZO
IGNITION BUTTON, PILOT SHOULD
LIGHT.
– WATER TEMPERATURE IS BELOW
THE CUT-OUT LIMIT
YES
STATUS LIGHT SHOULD FLASH AFTER
1 MINUTE, LED WILL FLASH NORMAL
SINGLE BLINK, RELEASE THE DEVICE
KNOB, PILOT SHOULD REMAIN LIT
YES
TURN DEVICE KNOB TO DESIRED
TEMPERATURE SETTING, BURNER WILL
TURN ON ONLY IN ACTIVE CALL FOR
HEAT (WATER TEMPERATURE IS LESS
THAN TEMPERATURE SETTING MINUS
DIFFERENTIAL); LED FLASHES 1 TIME
EVERY 3 SECONDS WHILE IDLE AND
STROBES EVERY 3 SECONDS DURING
A CALL FOR HEAT.
YES
SYSTEM OK
Fig. 6. Troubleshooting without status light.
NORMAL RANGE
OUTPUT TOO LOW
4
5
6
7
8
TIME (MINUTES)
CHECK:
• INLET PRESSURE
NO
• MAKE SURE AIR IS BLED OUT OF SYSTEM
• PIEZO SPARKING TO THERMOPILE
• CLOGGED PILOT ORIFICE
• GAS LEAK IN PILOT TUBING CONNECTIONS
CHECK:
• WIRING OF THERMOPILE LEADS
NO
• FLAME COVERAGE OF THERMOPILE
– THERMOPILE OUTPUT IS TOO LOW-RUN
•
THERMOPILE OUTPUT CHECK
CHECK:
NO
• EXCESSIVE INLET PRESSURE
• TANK TEMPERATURE IS AT OR CLOSE
TO SET POINT
INSTRUCTIONS TO THE
HOMEOWNER
WARNING
Fire or Explosion Hazard.
Can cause severe injury, death or property
damage.
1. IF YOU SMELL GAS:
•Turn off the gas supply at the appliance service
valve.
•Do not light any appliances in the house.
•Do not touch electrical switches or use the
phone. Leave the building and use a
neighbor's phone to call your gas supplier.
•If you cannot reach your gas supplier, call the
fire department.
2. The water heater control must be replaced in
event of any physical damage, tampering, bent
terminals, missing or broken parts, stripped
threads or evidence of exposure to heat.
WARNING
Scalding Hazard.
Can cause burns, severe injury or death.
Never move temperature setpoint knob past the
HOT setting without checking water temperature
at the faucet, and readjusting until comfortably
warm to the touch. Consider the ages and health
of all who will come into contact with heated water.
9
10
M22535B
7
WV8840A WATER HEATER CONTROLS
M29431
69-2247—05
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