The following is my understanding: The pump controller (blue box in 54s) receives voltage input from each of the Danfoss compressor controllers. The "fan output" terminal on the Danfoss is the output terminal that connects to the pump controller. The Danfoss fan output is 12 volts, regardless of whether the refrigeration unit is 12 or 24 volts.

Scott, you have me really thinking about this thorn in my side. My boat is on the hard now, but I am going to check the voltage coming out of the pump controller. If it is really 12 volts, then I think I am "missing the boat" by using 24-volt pumps. I no longer have the original Amel installation, so I am at a loss as to what came with the boat. I do feel, though, that running a 24-volt pump at 12 volts is asking for the problems which I have experience multiple times. I will investigate and see what is going on - I am an electrical engineer but do not want to profess any sort of expertise at this time. My old boat used keel-cooled units and I never had any issues - no pump!!
I will find out in the spring here in the US.
Jamie
A54 Phantom.