Calorifer issues, Im baffled

[volvopaul]

Hi , I’ve read all posts .

The boats domestic water pump that supplies clear hot or cold water to any taps or showers is nothing to do with the problem you have so dismiss any comments .

The issue is clearly that there is no heat transfer between the fresh domestic water inside the calorifier and the heating coil from the engine that circulates from the engine through the coil and back to the engine .
On some boats there is an in-line valve that can control the Temperature of the hot water produced irrespective of the engine temp should the engine temp exceed the stat temp setting .

There could either be a faulty fresh water pump, that is the pump on the engine not the boats domestic pressure pump , although if this was the case it would definitely overheat when the engine was run hard .
The engines fresh water pump is driven from the same belt as the alternator not the camshaft drive belt .
The engines sea water pump is located on top of the engine rear of the camshaft cover driven by a separate belt taken from the rear of the camshaft .

You problem sounds like a pure airlock which can be quite easily bled once the engine has some heat in it by disconnecting the return hose from the calorifier to the engine , just undo the clip , slide the hose away slightly and purge the air , you will loose some coolant but top up as req.
Check there is no inline restriction by possibly taking the hoses off and physically blowing through them .

If the circuit is blocked try attaching the marina hose pipe on to the system but not to the engine .
Enough there to keep you going .
Looking at your pics I may have serviced that boat or similar once at Penton Hook .

 

[Heckler]

Hi , I’ve read all posts .

The boats domestic water pump that supplies clear hot or cold water to any taps or showers is nothing to do with the problem you have so dismiss any comments .

The issue is clearly that there is no heat transfer between the fresh domestic water inside the calorifier and the heating coil from the engine that circulates from the engine through the coil and back to the engine .
On some boats there is an in-line valve that can control the Temperature of the hot water produced irrespective of the engine temp should the engine temp exceed the stat temp setting .

There could either be a faulty fresh water pump, that is the pump on the engine not the boats domestic pressure pump , although if this was the case it would definitely overheat when the engine was run hard .
The engines fresh water pump is driven from the same belt as the alternator not the camshaft drive belt .
The engines sea water pump is located on top of the engine rear of the camshaft cover driven by a separate belt taken from the rear of the camshaft .

You problem sounds like a pure airlock which can be quite easily bled once the engine has some heat in it by disconnecting the return hose from the calorifier to the engine , just undo the clip , slide the hose away slightly and purge the air , you will loose some coolant but top up as req.
Check there is no inline restriction by possibly taking the hoses off and physically blowing through them .

If the circuit is blocked try attaching the marina hose pipe on to the system but not to the engine .
Enough there to keep you going .
Looking at your pics I may have serviced that boat or similar once at Penton Hook .

My bad, the fresh water pump is driven by the fan belt. But the rest of the blurb stands. On mine if I run it for 30 mins the calorifier gets warm enough for her indoors and that is at 1500 rpm in neutral. I would normally run it in gear but at anchor not possible. The handbook says that there is a threaded plug on top of the thermostat housing which can be removed to bleed the calorifier system. I repeat my advice, start the engine from cold, feel the top of the thermostat housing whilst the outlet from the fresh water pump is also being felt. The outlet to the hose and the calorifier connection will warm up before the top of the thermostat housing until the thermostat opens. You will also feel the warmth going to the calorifier through one pipe and coming back through the other if there is circulation going on.

 

[Keith-i]

Quite simply there must be a blockage in the coolant pipes that run from the engine to the calorifier heat exchange coil. Either an air lock or debris. As the pipes warm up over a period of time it would suggest the 'blocakge' is close to or within the calorifier coil rather than at the engine end.

 

[lynallbel]

Hi , I’ve read all posts .

The boats domestic water pump that supplies clear hot or cold water to any taps or showers is nothing to do with the problem you have so dismiss any comments .

The issue is clearly that there is no heat transfer between the fresh domestic water inside the calorifier and the heating coil from the engine that circulates from the engine through the coil and back to the engine .
On some boats there is an in-line valve that can control the Temperature of the hot water produced irrespective of the engine temp should the engine temp exceed the stat temp setting .

There could either be a faulty fresh water pump, that is the pump on the engine not the boats domestic pressure pump , although if this was the case it would definitely overheat when the engine was run hard .
The engines fresh water pump is driven from the same belt as the alternator not the camshaft drive belt .
The engines sea water pump is located on top of the engine rear of the camshaft cover driven by a separate belt taken from the rear of the camshaft .

You problem sounds like a pure airlock which can be quite easily bled once the engine has some heat in it by disconnecting the return hose from the calorifier to the engine , just undo the clip , slide the hose away slightly and purge the air , you will loose some coolant but top up as req.
Check there is no inline restriction by possibly taking the hoses off and physically blowing through them .

If the circuit is blocked try attaching the marina hose pipe on to the system but not to the engine .
Enough there to keep you going .
Looking at your pics I may have serviced that boat or similar once at Penton Hook .

Thanks Paul, looks like Im going to be busy.
This boat came from Norfolk and I believe was up there for most of its life, but apparently there were only 25 hardy 27s made and there were several engine options, there cant be to many with the v/p n/a lumps so you never know.

 

[lynallbel]

Well finally got around to fixing this whilst servicing engines, new cambelts/fan belts/stats/oil/filters/impellors/sound insualtion/shaft greasers/engine bay lights/fire exts/water injection elbows and so on, the engine temp is now running higher (new stat) and hot water seems to be doing its thing, how long for we shall see!
I even cleaned the engines/bay and the bilge, came up quite smart.

 

[lynallbel]

Well once again we have no hot water when running the engine, so disocnnected engine hoses and coolant ran freely from them, so assume good, stuck a hose into the heating coil and got some brown lumps which eventually cleared, removed immersion element and checked tank all appears clean. inside.
Ran engine and we actaully have hot water, so I reckon them brown lumps were moving around as every now and then we would get a little hot water.

But and there is always a but I have somehow damaged the immersion element, which is now throwing the trip.
A direct replacement from a chandlers is 80 quid, yet a dual stat one from ebay is 20 quid, is there any good reason I have to buy the dearer version?

Original unit is made by Howden and is 1.25kw 11 inches long dual stat, cheapie from ebay is same length again with dual stats, but cannot see kw rating.

 

[lynallbel]

Cheapie

 

[lynallbel]

Acorn engineering, sensible prices and on the shelf.

 

[simonfraser]

How many more brown lumps are there
i‘d be thinking of cleaning the hoses out to prevent further issues

 

[Silvercloud]

Disconnect both pipes from the calorifier and then put a garden hose connected to the mains water ashore into the connection on the calorifier and push pressurised mains water through the coil.
This should clear any debris from the coil in the tank.
Then give the pipes from the engine a good clean out and this should solve your problem.

 

[plumbob]

Well once again we have no hot water when running the engine, so disocnnected engine hoses and coolant ran freely from them, so assume good, stuck a hose into the heating coil and got some brown lumps which eventually cleared, removed immersion element and checked tank all appears clean. inside.
Ran engine and we actaully have hot water, so I reckon them brown lumps were moving around as every now and then we would get a little hot water.

But and there is always a but I have somehow damaged the immersion element, which is now throwing the trip.
A direct replacement from a chandlers is 80 quid, yet a dual stat one from ebay is 20 quid, is there any good reason I have to buy the dearer version?

Original unit is made by Howden and is 1.25kw 11 inches long dual stat, cheapie from ebay is same length again with dual stats, but cannot see kw rating.

Very recently I have done the same job and replaced the same immersion heater as yours. Do not buy one from the plumbers merchant as these have no upper limit thermostat. Howdens still sell your model at over£150 . Simply go to Midland Chandler's and get the same length, made in Incaloy, twin stat, excellent service and approximately £25. Just make sure you get an immersion heater washer from Toolstation or the plumbers merchant as the new one comes with an O ring and probably won't seal under the pressure of the pump. A smear of Boss white on the washer face is vital too.
The new one is easy to wire in situ as the stat pocket allows the immersion to be fitted first and the stat after wiring.
Hope this helps.

 

[Rappey]

An indication of just how long it can take for the engine to heat water. A 2 hour run at 1000 rpm, hot water at tap barely manages luke warm

Wow. That's really bad. I have a bmc 1.5 .The calorifier feed leaves the engine where a car heater would have been fitted pumping hot cooling water before engine thermostat opens. In less than a mile the heated water is quite warm.
15 -20 mins and it's very hot. I also have a car heater matrix running from the same outlet which blows lovely hot air.
All of it is circulated by the engines own freshwater pump and has no apparent cooling effect on the engine.
Calorifier is higher than engine so bleeding the air out is a right pain but once done it works faultlessly.