What's up with my calorifier?...UPDATE

[NormanS]

My point is that it needs an electric pump. The one quoted on my website is stated to be unsuitable for salt water. Despite this Sadlers fitted them to all their raw-water cooled Bukhs as part of the calorifier installation and they lasted for years. The one originally in my boat lasted for 15 years, the replacement was about 6 years old when I changed out the engine.

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When I converted my old Gardner from raw cooling to fresh with a heat exchanger, I used a belt-driven Jabsco for circulating the fresh. Mind you, the Gardner was designed to run cooler than modern engines. It was to be between 130ºF and 140ºF, or "as hot as the hand can momentarily bear", according to the hand book.
The Jabsco pump did the job well, without any unforseen problems.

 

[J*O*A*M*O*N]

another guess????

My guess, works as a bypass around the thermostat (like the heater core of your car), engine not working at operating conditions....thermostat doesn't open and close so no flow through the heating coil. Flow powered by water pump.Possibly why you get warmed water till your engine reaches opp temp and the thermostat opens. Thermostats open and close to maintain the temp of your engine, and would therefore cycle flow through the water heater..hoses would also stay "warm" but not enough flow to heat water. Ed

 

[vyv_cox]

I suppose it depends on the internal passage ways. Could be that the flow through the calorifier only occurs as the thermostat opens and even on a steamer, as the Bukh is sometimes called, the thermostat will only open partially at light loads. The answer would be to take the thermostat housing off and look at the passageways.

But I agree with you - the easy option is a pump.

Yes, I had reached the same conclusion overnight. The 'brass manifold' is an extension to the thermostat housing. When the thermostat is closed there is no water flow through the engine, so nothing can pass to the calorifier. As the thermostat opens flow commences to the exhaust and the bypass is progressively closed. It would appear that water is now able to flow to the calorifier, although I still don't really understand why.

When motoring at the pontoon at lower revs the engine never gets hot enough to fully open the thermostat.

So between us all we seem to have answered the original question

 

[status]

In the photo of the manifold housing, what is the item with the grey cable running to it, my initial thought was temperature switch for over heat alarm but it seems quite large.

Dont think my bukh has one here but it is a younger model and a bit dificult to check at present.

Not a solenoid valve of any description is it?

Stuart

 

[vyv_cox]

It's the temperature switch. You can see it a little better in Snooks' original photo. There have been several designs of the thermostat housing, this looks like an early one.

 

[andythilo]

Sorry to jump on this bandwagon, but when you talk about a circulation pump, I assume your talking about on the cooling side, not the actual fresh water delivery?

Also is this pump in addition to the engines impeller pump? My system solely relies on the engine driven impeller pump to circulate the raw water through the various parts (engine, oil cooler, calorifier, etc..).

 

[Bosun Higgs]

Also is this pump in addition to the engines impeller pump? My system solely relies on the engine driven impeller pump to circulate the raw water through the various parts (engine, oil cooler, calorifier, etc..).

Yes it is. Sometimes it isnt necessary - a pals Moody 31 heats its water fine without an extra pump but my old Moody 336 needed one and my other pals Sadler 29 always had one.

Really raw water cooled engines arent ideal for calorifiers. The engines should be running round the 50 to 60C mark to minimise salt deposition and this is the typical tempoerature that a domestic hot water system is set at. So if you are taking small volumes of relatively cold water from the engine to try and heat your calorifier, you can see the basic problem.

Volvo technical told me that my old 2003 wasnt suitable for running a calorifier for the above reason but that didnt stop them selling the engine to Moody to do just that!

 

[andythilo]

My boat is freshwater only (rivers). Where would you install the in-line pump?

 

[vyv_cox]

My boat is freshwater only (rivers). Where would you install the in-line pump?

See my website, under engines. The pump is better on the return side, rather than the supply side as shown. Put it low down, around the bottom of the engine.