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Problem solving
Over-temperature detected by
outlet temperature sensor on hot
water pipe.
Temperature > 185°F
1. Check that the sensor is firmly attached to the vertical section of
the hot water pipe (see Fig. 69, page 52).
2. Check red wire connections at outlet temperature sensor.
Clean terminals with an eraser. If badly corroded, replace sensor
and wire harness. Check sensor resistance (see
Fig. 59, page
43
.
3. Clean inlet filter screen per chapter
6.2, page 27 and clear any
debris out of shower heads, faucet aerators and whole house
filters.
4. In areas where water has a high mineral content, periodic
descaling may be necessary. See chapter
6.3, page 27 for
directions.
Cold water temperature sensor
fault.
1. Check connector on wires coming from top of watervalve for a
secure connection. See Fig.
63, page 46.
2. Sensor may trip if water temperature drops below freezing to
protect heater from freezing conditions Any damage due to
freezing conditions is not covered under warranty.
Backflow temperature sensor over
309°F.
The appliance will close the burner
and lock.
1. Check combustion air and backflow vent piping for blockage.
2. Check if secondary fan connections are disconnected.
3. Check venting specifications are met. Long vent lengths,
venting with more than three elbows, blocked vent or combination
venting may cause this failure.
4. Check sensor resistance (see
Fig. 61, page 44).
Overheat sensor (ECO) open
circuit (should reset when cooler
temperatures are detected).
1. Disconnect power supply cord and check wire connections on
overheat sensor (top right of heat exchanger) and the two
connectors on the control board. See Fig.
63, page 46.
2. Check white wire connections at overheat sensor. Clean
terminals with an eraser. If badly corroded, replace sensor and
wire harness.
3. Check venting specifications are met. Long vent lengths,
venting with more than three elbows, blocked vent or combination
venting may cause this failure.
4. Clean inlet filter screen and clear any debris out of shower
heads, faucet aerators and whole house filters.
5. In areas where water has a high mineral content, periodic
descaling may necessary, see
chapter 6.3.
6. Unplug power supply cord to the water heater. Open a hot
water tap for several minutes to allow cold water to pass through
heat exchanger. Close hot water tap and disconnect lead wires to
overheat sensor. Using a multimeter, check continuity through
overheat sensor contacts. Replace sensor if open.
Display Cause Solution
Table 20
* By installer or service technician only.