Just to put some additional pictures with your story
The original pump as found on our Amel (hull 121) is the one in picture 1. It has the code A092819C like the one you specified. Our boat had indeed 2 pumps mounted next to each other, looking quite sad at the time we bought the boat. These are indeed a rebadged Flojet pump.
When I ordered the new pumps from Frigoboat, I received the pump in picture 2 and 3. It has the code R4105343 and Frigoboat put a sticker over it with a serial number and a notification the pump runs on 12 Volt.
As you can see it is a 24 Volt pump that they use at 12 Volt. That seemed a good idea at the time but nine moths in the tropics caused the commutator to look like picture 4. The copper is completely worn away and the pump is beyond repair. According to Flojet this is an intermittent duty pump.
I tried using a brushless mag-drive pump using about 1.3 Amps @ 12 Volt but these are centrifugal pumps that simply do not deliver enough pressure to overcome the resistance in the pipes to produce a decent flow. I’ve been told you need at least 6 liters per minute to keep the compressors happy.
I’m now using the Flojet pump you mention as well, the 4105-512 accepting for now the pump will need replacement quite frequently.
I admire the work that Oliver did with replacing the insulation of the freezer cabinet. That seems by far the best thing to do for the tropics. Also replacing the motor of the Flojet pump with a brushless motor seems a very good idea. These two modifications would solve 80% of the problem.
The remainder ideally would be solved by using a circulation system with heat radiators on the underside of the boat. and using coolant liquid as circulation fluid. But that would mean additional holes in the boat and all the rest,
But for now my first action is to get a brushless motor for the Flojet pump-head.