Calorifier heating engine .

[andy59]

While doing some odd jobs on the boat at the weekend , i noticed that when the hot water is on the heating circuit gets hot and the starboard engine is warming up nicely £££££££ . Does anyone know how i can stop this happening or shall i just leave the hot water on in the cold weather to keep the engine bay nice and toasty .

 

[LionsDen]

While doing some odd jobs on the boat at the weekend , i noticed that when the hot water is on the heating circuit gets hot and the starboard engine is warming up nicely £££££££ . Does anyone know how i can stop this happening or shall i just leave the hot water on in the cold weather to keep the engine bay nice and toasty .

I would keep it on as will keep th eengie bay reasonably dry or install a couple of tube heaters instead

 

[LionsDen]

While doing some odd jobs on the boat at the weekend , i noticed that when the hot water is on the heating circuit gets hot and the starboard engine is warming up nicely £££££££ . Does anyone know how i can stop this happening or shall i just leave the hot water on in the cold weather to keep the engine bay nice and toasty .

I would keep it on as will keep the engie bay reasonably dry or install a couple of tube heaters instead

 

[andy59]

I wouldnt mind leaving it on apart from the fact that the little red flashy thing on the metermaid seems to speed up .

 

[oldgit]

present boat does same thing......as did previous one,prob some gadget out there to fix it but apart from cost of etrickery appears to do no harm

 

[BGW]

While doing some odd jobs on the boat at the weekend , i noticed that when the hot water is on the heating circuit gets hot and the starboard engine is warming up nicely £££££££ . Does anyone know how i can stop this happening or shall i just leave the hot water on in the cold weather to keep the engine bay nice and toasty .

It is due to the run of the pipes - they need to go down a reasonable distance from the calorifier before they go back up to the engine to stop the thermosyphon effect.

I am sure I read that keeping the engine warm like this was bad as it encouraged the oil to run off components rather than stay stuck for the next start-up.

 

[gravygraham]

Not sure how sensitive you are to big electric bills? Fwiw I'd fit one or two tubular heaters coupled to a thermostat set at say five or ten degrees.

 

[andy59]

I think I will put a drop down loop in one of the hoses to see if it stops it . Have been looking for a 12v valve that would open when engine is running but can't seem to find one . Also i would think that when at anchor after a run with a nice full tank of hot water , the thermosyphon has the effect of losing the heat fom the calorifier to the engine

 

[Tugw]

Doesnt your calorifier have its own isolation switch?

 

[andy59]

Not sure how sensitive you are to big electric bills? Fwiw I'd fit one or two tubular heaters coupled to a thermostat set at say five or ten degrees.

I already have those Graham , I'm just trying to stop losing heat from calorifier to engine .

 

[PaulGooch]

I think I will put a drop down loop in one of the hoses to see if it stops it . Have been looking for a 12v valve that would open when engine is running but can't seem to find one . Also i would think that when at anchor after a run with a nice full tank of hot water , the thermosyphon has the effect of losing the heat fom the calorifier to the engine

http://www.ebay.co.uk/itm/motorized...80995417984?pt=UK_Gadgets&hash=item416ca1cf80

I'd be inclined to go the loop route i think.

 

[Glyn-2008]

I think I will put a drop down loop in one of the hoses to see if it stops it . Have been looking for a 12v valve that would open when engine is running but can't seem to find one . Also i would think that when at anchor after a run with a nice full tank of hot water , the thermosyphon has the effect of losing the heat fom the calorifier to the engine

You could always use a 230volt valve (normaly open) and join it to the wires feeding the heating element in the calorifier. When the imersion heater is switched on the valve will be closed. As soon as the shore power is off (ie. when you leave the berth) the valve will be naturaly open.

 

[andy59]

You could always use a 230volt valve (normaly open) and join it to the wires feeding the heating element in the calorifier. When the imersion heater is switched on the valve will be closed. As soon as the shore power is off (ie. when you leave the berth) the valve will be naturaly open.

I had thought of that Glyn but when at anchor the heat will still thermosyphon back to the engine , I think I need a 12volt sprung return valve that only opens when engine running , then when engine off , valve closes and thermosyphon stops

 

[PaulGooch]

I had thought of that Glyn but when at anchor the heat will still thermosyphon back to the engine , I think I need a 12volt sprung return valve that only opens when engine running , then when engine off , valve closes and thermosyphon stops

Like the one i linked to ?

Or this one : http://shop.solarproject.co.uk/sp333-three-port-motorised-valve-p-20.html

Diverts flow when two wires are given 12V feed. If you put a blank in one of the default ports there would be no flow with the engine off, wire it to the ignition on the engine that is connected to the calorifier and with the engine run the water is allowed to flow through the calorifier.

 

[andy59]

Like the one i linked to ?

Or this one : http://shop.solarproject.co.uk/sp333-three-port-motorised-valve-p-20.html

Diverts flow when two wires are given 12V feed. If you put a blank in one of the default ports there would be no flow with the engine off, wire it to the ignition on the engine that is connected to the calorifier and with the engine run the water is allowed to flow through the calorifier.

Thanks Paul , that's perfect . Will get it fitted and let you know how well it works .

 

[Momac]

Just a thought - would a check valve do the job?
http://www.bes.co.uk/product/98~PL~1732~1732~-Swing-Check-Valves-.html

I guess it might restrict the flow when using the engine for water heating?

 

[andy59]

Don't see why it shouldn't Martyn , if the engine water pump has enough "push" to overcome the check valve . And TBO it's a much cheaper option if it works .

 

[Hoolie]

Along similar lines, you could use a central heating non-return valve. They're a spring loaded ball that the pump can easily overcome but gravity thermal circulation can't.

 

[Dave_Seager]

When the engine is running, water should be pumped from the engine to the top of the coil in the calorifier and will return from the bottom.

When the engine is stopped and is cooler than the calorifier you may get convection from the top of the hot calorifier to the engine where the water cools, becomes denser and flows back to the bottom of the calorifier.

Since the unwanted flow is in the opposite direction to the normal operation a simple non-return valve (check valve) can be used to prevent it. As the flow will be quite slow, mount the valve so that it will close under gravity rather than relying on the flow of water to close it or use a valve with a light spring.

 

[vyv_cox]

Don't see why it shouldn't Martyn , if the engine water pump has enough "push" to overcome the check valve . And TBO it's a much cheaper option if it works .

I use exactly this method at home to prevent hot water from circulating through the radiators by convection when only the domestic hot water tank is being heated. It works perfectly and has done for many years.

However, this is a well known issue with calorifiers in boats, which a down loop in the supply hoses will eradicate.