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

Rudolf Waldispuehl

Hi all  

First I have to say the Fridge-cooling on WASABI is running fine and constantly since 3 years without any issue (living 8-10 Month per year on WASABI). I never replaced the pump and it’s running many hours a day. Nevertheless I bought a spare Frigoboat Pump and a spare controller just in case (see pics).

I have no idea why these pump is always breaking @ other A54. Maybe not using the original pumps? So I hear Bill Rouse saying: “Always use original parts as designed for the boat” ;-)


I try to explain what the E51385 is doing in my opinion and excuse me if I bother you with broadly known information. 

-       The Frigoboat E51385 is a DC24-12V converter and power driver to source the needed AMP’s to the pump, because the Fan output F port (which is minus) is not designed to deliver enough Amp’s for the pump on 12V. The E51385 is a Voltage driver (converter) as noted on the schema, which was in my Pump-Box (see Pictures attached).

-       The mentioned schema also shows that if I run a 12V boat Voltage, I can connect the pump with an extra relay controlled by the Fan output, but power-sourced for the pump is the house-battery. Electrically the same as Bill’s proposal. 

-       I opened my spare box and you can see in the middle of the board the blue 12V potentio-meter (or trimmer, - sorry my English is not perfect). It’s the converter regulator to bring any 24V down to 12V. Therefore the Frigoboat controller should never deliver 24V to the pump.


I know it’s very confusing that the controller shows the 24V LED on. The LED just indicates; “these is a 24V driven boat”. The LED shows 24V because the Battery Minus goes directly to the E51385. So it shows the 24V between the minus and the plus coming from the FAN-Output (+).  The plus from the Danfos controller is the same plus as the input source and gives 24V against the minus at the E51385. The F wire (-) is only the trigger wire. All together it sounds strange but these 24V is converting to 12V at the E51385 for the pump. Don't be confused with the 24V LED.

Bill’s proposed project is more clear and will certainly run as well. But it’s more or less the same with electrical (discrete components) as the E51385 which is build with transistor components electronically.  In conclusion: 

I don’t think Bill's solution will change the wear of a pump and the problem will stay unless these Frigoboat converters are doing something strange which harms the pumps (but I don’t think so).

Hope this helps a bit to get light into the blue Frigoboard “magic box”, and excuse my limited English.


Best regards

Ruedi and Sabina Waldispuehl

AMEL-54 Nbr. 55

Currently in Santa Maria di Leuca 

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