Measure the voltage through the
temperature limiter (FD1).
Has the temperature limiter been
mechanically tripped?
NO
YES
NO
Is there 230 V between J8:45-46
on the relay board (AA6)?
Check wiring.
Can it be reset mechanically when
the temperature is < 80 °C?
Is the voltage supply OK?
Replace relay card AA6.
YES
NO
YES
Was the hot water temperature
greater than 90 °C when the alarm
was tripped, according to the
alarm log?
Action.
Replace temperature
limiter.
NO
YES
Check the function of contactors
QA1, QA2 and QA3.
YES
Check the characteristics
of the immersion heater
sensor and that it is
correctly positioned.
NO
Is the voltage supply OK?
YES
NO
Check contactor QA10 and wiring
to the outdoor unit.
Action.
Action.
Has miniature circuit breaker FA2
tripped?
NO
YES
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