Perkins 4.108

Liz_I

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Does anyone know how to test the heat exchanger for leaks. The calorifier was slowly losing fresh water and it seems that the heat exchanger is the most likely problem.
TIA.
 

pappaecho

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Most calorifiers are smaller versions of the copper hot water tanks used in the UK in housing, and as such the heat exchanger is a simple copper coil. If you disconnect it from the engine colling system, you can use a car type pump to test it. Such coil could withstand 30 bar without problems, even though 2 bar will be adequate for onboard pressure.
Frankly it is very rare for a coil to fail because of its thickness
 

Tranona

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If the calorifier is losing water it is unlikely to be connected with the heat exchanger on the engine as the flow from the engine cooling system through the coil which is isolated from the boats water system.
 

ukmctc

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If the calorifier is losing water it is unlikely to be connected with the heat exchanger on the engine as the flow from the engine cooling system through the coil which is isolated from the boats water system.

Incorrect, on the Perkins 4 108, the water pipe used is the hose from to the heat exchanger, it goes into the calorifier and back out, then connects back to the engine water system and goes back to the rad to cool. if water was being lost it would either be leaking into the fresh water system or fresh water into the engine system.
Try running food dye through the engine rad and see if it turns up in the water system or visaversa in the frest water tank and see if it appears in the engine rad. at least then you'll see if its leaking at all.
You will also then see overboard if the heat exchanger is leaking out into the exhaust system. Worth a try if there is no water, fresh or otherwise in the bilges.
 

Billjratt

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The calorifier losing FRESH water CANNOT be due to the heat exchanger on the engine.
The fresh water is only in contact with the calorifier walls - any leaks visible? or the heating coil containing engine coolant. If it is getting lost into the engine coolant, the engine header tank will give evidence of over-filling*, however, the problem will be a leak in the calorifier coil, not the heat exchanger.
Note * On mine, the overflow tube just runs down into the bilge, find yours and stick it's end in a bottle to see if it fills.
How do you know you're losing fresh water from the calorifier and not somewhere else in the system?
Have you tested the "fresh" hot water for additional antifreeze? - When the engine is up to temperature, the pressure in it's cooling system could be greater than that of the hotwater system- especially when the hot tap is turned on.
Does the domestic pump "burp" occasionally all on it's own (more noticeable during the night).
If fresh water from either hot or cold system goes missing, the pump will try to make it up again to keep the accumulator under pressure.
What's in the bilges - and where. Talcom powder may need to be applied to trace the leak.
 
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