calorifier

baggypipes

baggypipes

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Hi Flushed through the water system begining of winter. Run the engine for half hour, no hot water comming through (no problem when using the emersion). One of the pipes to the calorifier gets warm the other stays cold. tried as you would with a car, ie airlock, tried flushing through with hose pipe water passing through, no probs. Still water to the taps is cold, any advice welcome. Many thanks
 
We have that problem. The engine doesn't get hot enough in cold seawater to heat the engine enough to heat the calorifier water. If yours has worked before I would check the impellor hasn't lost some bits and the thermostat is working properly.
 
I'd still bet on an airlock.( because the inference is that it was working before you flushed it)
Maybe not in the calorifier coil circuit, but somewhere else in the engine cooling system. Have you run the engine in gear long enough to ascertain that it's temperature is same as last year?
Does the thermal gradient on the heat-exchanger seem normal?
My 4108 has plugs in the head and exhaust manifold for bleeding air from the system. Do you have an extra pump to assist the calorifier flow?
Engine type?
 
The one time we ran into this problem after the winter, when I checked the coolant level in the heat exchanger, it was a bit low. Topped up the collant, ran the engine for about 15 minutes under load and warm water was the result.

If the coolant level is OK, then it sounds like you may have an airlock in the calorifier. Try undoing the end of the cool hose and using a pumpt to suck coolant through it to clear the airlock - remember to top up the levels to compensate for this.
 
Billjratt said:
I'd still bet on an airlock.( because the inference is that it was working before you flushed it)
Maybe not in the calorifier coil circuit, but somewhere else in the engine cooling system. Have you run the engine in gear long enough to ascertain that it's temperature is same as last year?
Does the thermal gradient on the heat-exchanger seem normal?
My 4108 has plugs in the head and exhaust manifold for bleeding air from the system. Do you have an extra pump to assist the calorifier flow?
Engine type?
Click to expand...

Hi This time i ran the engine for half hour last time i tried to sort this, a couple of months ago i ran for over an hour always in gear, as you will be aware the sea is still rather cold. I changed the thermostat & checked the impellor. I also ran a hose through the engine water system & through the calorifier. The engine temp gauge only whent upto about 50 iv'e been told the normal working temp should be 75-80. May be thats a problem. Has a plug on the heat exchanger, water comes out there ok. Dont have a pump to assist the calorifier never needed it.
Engine is Lister petter 40 hp.
When one hose is off the calorifier no water comes out unless the engine is running fast, this is why i wonderd if it is an airlock, having had trouble with a car system.
 
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I had the same problem (Bukh DV20, raw water cooled). Turned out to be a bit of crud blocking the hot outlet at the base of the manifold.

John
 
It sounds very much like an airlock. Try blocking off the fresh water supply to the heat exchanger with a mole wrench to divert the full flow through the calorifier. The ultimate method is to remove one hose from the calorifier coil, lift it up and backfill with water until it flows permanently from the other.
 
I'm not familiar with your engine, but if you can see into the header tank through the filler, you may be able to check for water flowing in from the system.
Normally, ( I think) you shouldn't see anything until the thermostat opens, then there will be a gush which may stop again if the fresh fluid in the heat exchanger is cool enough. (the calorifier circuit should be flowing all the time and the pipe should feel warm long before the thermostat opens)

So, if it's flowing all the time, the thermostat may not be closing or wrong type or badly seated. If it doesn't gush, there may be an airlock causing flow disruption, but assuming the header tank is full, I would expect the guage to register an overheat after a short time.

You say there is no heat in the calorifier return pipe. Is the input side really hot? - ie a huge temperature gradient across the calorifier?

You haven't got the pipes mixed up have you?

Can you think back to EVERYTHING you've done/moved since the system was working correctly please, it's got to be something (or a result of something) on that list.

What happens if you "short" the input and output pipes at the calorifier with a piece of clear hose - heat all the way? evidence of movement, bubbles?

Is the water coming out of the tap OK (no antifreeze!!!)?

That's me exhausted. Now it's your turn, good luck!
 
Billjratt said:
I'm not familiar with your engine, but if you can see into the header tank through the filler, you may be able to check for water flowing in from the system.
Normally, ( I think) you shouldn't see anything until the thermostat opens, then there will be a gush which may stop again if the fresh fluid in the heat exchanger is cool enough. (the calorifier circuit should be flowing all the time and the pipe should feel warm long before the thermostat opens)

So, if it's flowing all the time, the thermostat may not be closing or wrong type or badly seated. If it doesn't gush, there may be an airlock causing flow disruption, but assuming the header tank is full, I would expect the guage to register an overheat after a short time.

You say there is no heat in the calorifier return pipe. Is the input side really hot? - ie a huge temperature gradient across the calorifier?

You haven't got the pipes mixed up have you?

Can you think back to EVERYTHING you've done/moved since the system was working correctly please, it's got to be something (or a result of something) on that list.

What happens if you "short" the input and output pipes at the calorifier with a piece of clear hose - heat all the way? evidence of movement, bubbles?

Is the water coming out of the tap OK (no antifreeze!!!)?

That's me exhausted. Now it's your turn, good luck!
Click to expand...

Sorry can you repeat that wasn't concentrating the wife making me eat rosemary bread. lol
Very many thanks for your input much appreciated:
The ONLY thing i have done is to drain the system & fill with antifreeze, not taken any pipes off to muddle up. As i said water only comes out if running the engine fast. It does seem to be an airlock but cant clear it, will have another go now the weather has improved here in Troon. Will post any result. Cheers
 
If the engine is not getting hot, the calorifier won't either.
It could be the thermostat has failed in the open state. This would also mean the engine does not pump water around the bypass/heater circuit (as it would be on a car) where the calorifier is, it dumps it to the heat exchanger.

If the cylinder head is getting hot, then think airlock, blockage, freshwater pump failure or other cause of no circulation.
 
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