Calorifier not working

[yerffoeg]

I fitted a calorifier on my boat some years ago but it has never worked: the coolant in the hose from engine to calorifier (Volvo penta 2020) gets hot only about 6 inches from the engine, but no further. The calorifier is mounted below the engine block. The problem may be because of the curve in the hosing, which goes down into a deep locker where the small calorifier is located. Vyv Cox gave me some useful advice and suggested an additional pump to assist the coolant circulation, as per the diagram on his website, but I was wondering if there were any other possible solutions.

 

[PCUK]

The calorifier should be roughly at the same height as the engine to allow natural circulation.

 

[Otter]

If the hot water pipe from the engine slants down at a steep angel I'm not surprised the hot water won't go down there! If Vyv has suggested a pump then that's the way to go, it's only about £17 and it's only running when the engine's on.

 

[RobBrown]

When I retro-fitted a calorifier to my raw water cooled Bukh DV 20, the take -off etc kit included a Johnson circulating pump. I agree with Vyv that one is likely to be required to get any circulating hot water in that situation, tho I believe a 2020 is indirect cooling, so it might be different.

 

[vyv_cox]

If it is an indirectly cooled engine I would expect the engine's pump to be perfectly capable of doing the job, just like the heater in your car. If that is your engine type then the problem is an air lock. Remove the hoses from the engine, fill the calorifier coil with a hose pipe until you are certain it is full.

If indirectly cooled then an auxiliary pump will probably be needed. Airlocks are also a problem and make sure that the pump is working with the thermosiphon in the calorifier, i.e. Hot water in at the top, out at the bottom.