A.O. Smith CAWH 8-455-6 Installation, User And Service Manual page 68

Indication
Insufficient or no hot
water
EN
Earth leakage circuit
breaker is out
Abnormal sounds
A safety device is acti-
vated
66
Cause
The water heater is off.
The temperature is set too low.
There is no supply voltage.
The hot water supply is used up.
A safety device is activated.
There is not enough water in the tank.
One of the heating elements is defec-
tive.
Normal expansion and contraction of
metal parts during periods of heat-up
and cool-down
Sediment buildup on or around the ele-
ments.
The heat pump compressor or fan is
running
The safety thermostat (Q) is activated.
The thermal fuse broke the control cir-
cuit
Measure
Turn on the water heater (see 4.1).
Set the setpoint higher.
Make sure that:
- the isolator is in ON position.
- there is power on the isolator.
- there is power to the electrical connec-
tor block.
The measured voltage must be
400 V (-15%, +10%).
AC
Reduce the hot water consumption. Wait un-
til the water heater heats up.
- Make sure that the voltage between
the connections of the heating ele-
ments is 230VAC (-15%, +10%).
- Refer to indication "A safety device is
activated", next page.
- Make sure that the water heater is fil-
led with water.
- Measure the resistance value between
each heating element connection and
the outside of the tank. The value
must be infinite.
- Determine which element is defective.
- No action required.
- Drain and flush the tank as directed.
See the draining and suction section.
- No action required
- Make sure the water heater is com-
pletely filled.
- Tap off water, so the temperature
drops in the water heater.
- Make sure all connections are connec-
ted properly (refer to the wiring dia-
gram).
- Use the red button to manually reset
the thermostat.
- If necessary, replace the safety ther-
mostat (Q).
- Replace the CCB
Installation, Maintenance and Service part