Re: New Thread on A54 fridge pumps (ATTN: OLIVER Vela Nautica)

Dean Gillies

Bill, in answer to your burning question.

The 24V supply comes from the Danfoss interface on the pins adjacent to the F pins. So, numbering the pins on the pump  interface From left to right as 1 thru 7. Pins 1,3 and 5 carry 24V supplied from Danfoss unit, pins 2,4 and 6 carry the F signals (0V or 12V) each of from the Danfoss controllers, pins 7 and 8 feed the pump and pin 9 is 0V (Negative battery terminal).

The F pins driving to 12V triggers the 51385 to operate the pump, using the power derived from pins 1,3 and 5.

If there is 24V on the F terminals then the Danfoss unit is indeed broken. I think this is highly unlikely. Wish I was on a boat to check too.

However, I'll stick my neck out here and say that I believe that 24V driven to the pump indicates a failed 51385 and not a failed Danfoss controller 🤔

best regards
SY Stella

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