92
Issue 2 14/07/16
10 Appendix
10.5 Service procedure D24-I
10.5.1 Thermostat circuit testing
This procedure assumes the flue damper is in working order. Be
sure damper opens under its own power when the thermostat
circuit is by-passed. Damper must be open or removed during
this test. Do not force damper open using your hands or tools.
Caution
Be Careful When Making Voltage Measurements or
Jumping Terminals Not to Damage or Deform Connectors
or Connector Pins.
Danger
120 volt exposure. To avoid personal injury, use caution
while performing this procedure.
Condition: Water Heater Not
Operating Display shows error code
“31” (Upper Sensor Readings Faulty)
or error code “32” (Lower Sensor
Readings Faulty)
See next page
If sensor clip is
damaged replace
clip. Replace lower
sensor if damaged.
Check Sensor
Resistance
Unplug or disconnect electrical power to
the water heater
Check continuity of wire harness to
affected sensor. Measurement of
ohmmeter should be close to 0 ohms.
Replace wire harness if high resistance
is measured (over 0.5 ohms) Check
wires for intermittent connections, shorts,
frayed insulation. Replace if necessary
If wire harness checks out O.K.check
resistance of sensor. Refer to section on
Sensor Resistance Testing. If sensor
resistance is not near the values shown in
the table, then replace upper or lower
sensor as indicated by error code number.
Turn power on to water heater. Run
water heater through heating cycle and
verify proper operation. Sensor
temperature can be viewed when burner
shuts off (see section on viewing the
display in “Service Mode”.
Check lower sensor. Is the sensor fully
inserted into the well? Sensor is held in
place with a clip fastened to the well
Check lower sensor wire making sure it
is not damaged or has breaks in the wire
insulation. Check upper harness wires to
upper sensor, if used (some models).
Turn power “OFF”. Draw water to cool
tank below 49°C
Condition: Water Heater Not Operating
Display shows error code “65” High
Water Temperature (over 93°C)
WARNING!
Do not reset the display from the hard
lockout state without correcting the
cause of the overheating condition.
No
Yes
Summary of Contents for 24/39
Page 1: ......
Page 112: ...112 Issue 2 14 07 16 ...
Page 113: ...Issue 2 14 07 16 113 ...
Page 114: ...114 Issue 2 14 07 16 ...