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Today for the first time we had no hot water, now a technical question my boat is keel cooled and where the pipes go through the hull there is a “T” piece which goes to the Calorifier. My question is why is it not plumbed in series with the keel cooler as the water would then pass through the keel cooler then the Calorifier and back to the engine.  
 

Thanks in advance.  

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The hot water circuit should really be on a bypass of the thermostat so the water gets heat long before the keel cooler gets any hot water, while the engine is under temp no hot coolant shoud flow through the keel cooler or it would take forever to warm up.

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Up until today we always got lots of good hot water. The engine temp normally runs at 85’ but today it was just over 90’  but the header tank was only 80’.   My best guess is air in the hot water circuit somewhere but bleeding it is not easy. 

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Hey Doug - 'B.A' has loadsa hot water always in stock, lashings of the stuff in fact and it is also the 'Good' stuff too.

We'll see you at the wooden boat show at Beccles if not before - you can have some if you like?  Shall I bring another bucket? :default_icon_e_biggrin:

Griff

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13 hours ago, BrundallNavy said:

Up until today we always got lots of good hot water. The engine temp normally runs at 85’ but today it was just over 90’  but the header tank was only 80’.   My best guess is air in the hot water circuit somewhere but bleeding it is not easy. 

You don’t just get air in the circuit. So unless you ran low you have an air leak. 
Do you mean the header tank on the engine or the hot water tank?

 

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1 hour ago, Cheesey69 said:

You don’t just get air in the circuit. So unless you ran low you have an air leak. 
Do you mean the header tank on the engine or the hot water tank?

 

The engine was out over the winter and being keel cooled it’s a right pig to bleed. The only way is to connect a hose pipe to the pipe into the keel cooler and let it flood out of the header tank, trouble is it take the path of least resistance bypassing the Calorifier. 

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Have you checked the condition of the impellor? It sounds like the coolant isn't being pumped properly around the engine and apart from low coolant, can only really be air lock, worn or failing impellor or jammed thermostat.

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I've got the same set up as you on Chloe Jane Doug.

I take the upper engine fed pipe off the calorifier and pour coolant into the removed pipe manually until water starts to come out the connection you took the pipe off of. Then quickly reconnect the pipe. Job done!

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Hi The supply to the calorifierer should come from the top of the engine head at the rear (in a vehicle this would be the heater ) this is pumped/moved by the engine impeller, the cooling hose to the keel cooling or heat exchanger should come from the top hose connection after the engine thermostat( which maintains a constant temp in the engine), the impeller if you have one only pumps river water from strainer in hull through heat exchanger then into exhaust pipe, you need to bleed the hose at the top of the calorifirer  by removing the rad cap then slacken the hose clip pull the hose of so it just makes contact start engine on fast tick over allow hose to come free to leave a gap until just water comes out push hose back on then top up engine with 50/50 coolant, the hose from the engine should go to top connection on calorfier and lower pipe ie return goes to the water pump, this applys to the engine hoses to keel cooling /hot in top return from bottom/lower, if you have any thing different it is not correct, even if it works. your tee piece might be for the return from the califierer into bottom hose of engine.You should have a 50/50 mixture in cooling system other wise you will get corosion and rust in cooling system which will block flow have you checked thermostat? to do this start up after a short while feel top hose this should be cold if thermostat is closed if warm thermostat is faulty hose should be coldish until thermostat opens at correct engine temp then will get suddenly hot. John

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Oh one other point if you fit a bleed screw or small dia hose back to header tank from top hose on keel cooling tank( from car radiater) this would make bleeding easy and not loose your coolant. John

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1 hour ago, Meantime said:

Have you checked the condition of the impellor? It sounds like the coolant isn't being pumped properly around the engine and apart from low coolant, can only really be air lock, worn or failing impellor or jammed thermostat.

The engine cooling circuit should be pumped by the engine circulation pump. The impellor would, in most circumstances, have nothing to do with this. Keel cooled engines would generally only require raw water to cool the exhaust, assuming it's a water-cooled exhaust. 

 

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If you fit a bleed screw or two in convenient places you could suck the coolant through with an oil sucker (pela type) and be fully mess free as all the coolant will be in the oil sucker ready to be tipped straight back into header.

I use one for bleeding my diesel system at filter changes, makes the job an absolute doddle.

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On 25/07/2021 at 11:37, annv said:

Hi The supply to the calorifierer should come from the top of the engine head at the rear (in a vehicle this would be the heater ) this is pumped/moved by the engine impeller, the cooling hose to the keel cooling or heat exchanger should come from the top hose connection after the engine thermostat( which maintains a constant temp in the engine), the impeller if you have one only pumps river water from strainer in hull through heat exchanger then into exhaust pipe, you need to bleed the hose at the top of the calorifirer  by removing the rad cap then slacken the hose clip pull the hose of so it just makes contact start engine on fast tick over allow hose to come free to leave a gap until just water comes out push hose back on then top up engine with 50/50 coolant, the hose from the engine should go to top connection on calorfier and lower pipe ie return goes to the water pump, this applys to the engine hoses to keel cooling /hot in top return from bottom/lower, if you have any thing different it is not correct, even if it works. your tee piece might be for the return from the califierer into bottom hose of engine.You should have a 50/50 mixture in cooling system other wise you will get corosion and rust in cooling system which will block flow have you checked thermostat? to do this start up after a short while feel top hose this should be cold if thermostat is closed if warm thermostat is faulty hose should be coldish until thermostat opens at correct engine temp then will get suddenly hot. John

Spot on John, was an air lock in the tank and the hose support had broken allowing the hose to drop creating a vertical pipe which the water would not climb. Pipe re supported and bleed, now back to normal service.  

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  • 2 weeks later...

After a couple of days of having hot water we now don’t. Going over John’s post I think it may be plumbed wrong. In my defence I didn’t remove the engine so I am not sure what came off where. 
the hose from the thermostat goes into the header tank and the hose out goes to the keel cooler which also has the return from the calorfier the bottom hose from the engine also goes to the keel cooler. 

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578471D9-7DBD-490E-845B-1EDE3161C601.jpeg

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Hi Doug the hoses orientation sound ok providing the top hose goes into the top of keel cooler and bottom hose comes from the bottom/lower outlet, if you had hot water but not now re bleed the top hose into calorfiere if air is there you have a hose that's not air tight ie as engine cools it creates a vacuum in header tank (providing) rad cap is sealing, check all joints or pressurize the cooling system if no leaks and holds pressure re torque the head bolts/nuts as head gasket could be not sealing. Why/what did you have done to require hoses to be removed/taken off? John

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14 minutes ago, annv said:

Hi Doug the hoses orientation sound ok providing the top hose goes into the top of keel cooler and bottom hose comes from the bottom/lower outlet, if you had hot water but not now re bleed the top hose into calorfiere if air is there you have a hose that's not air tight ie as engine cools it creates a vacuum in header tank (providing) rad cap is sealing, check all joints or pressurize the cooling system if no leaks and holds pressure re torque the head bolts/nuts as head gasket could be not sealing. Why/what did you have done to require hoses to be removed/taken off? John

Hi John. 
The engine was removed by Martham at the end of November last year to allow me to replace two broken ribs underneath the engine tray but due to lockdown we didn’t get round to doing them so put the engine back in in May. After a few problems bleeding the keel cooler. It has been fine until last weekend when we suddenly lost hot water. 
 

I have just had another look and the keel cooler pipes must be correct as they won’t fit the other way round as one is a lot shorter than the other. I removed the bottom hose from the calorifier and ran the engine but no flow, top hose removed and very little flow next the hose from the rear of the cylinder head and a good flow which leads me to a collapsed hose. I will change this any way and see if that cures it as that would go with suddenly losing hot water. 

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Hi You wont get any flow from bottom hos to calorfiera the flow should be from top/rear of engine to top of calorfiera then out of calorfira back to engine bottom hose if no flow from hose its blocked/collapsed replace, dont forget 50/50 antifreeze. John

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Had this in the past with dads boat, also installed with a keel cooler. They can be prone to air locks normally if there is a small leak or if the pipe feeding the clarorfiera has dropped. If not tried already flush it through with a hose pipe, so there’s only water coming from the feed back to the engine. With quick hands remake the connections. 

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