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bargebird

Calorifier not heating when moored-up

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When I'm cruising at 1200 to 1300rpm my calorifier heats the water perfectly but when i'm moored and using the engine at 900rpm or so for battery charging the calorifier water doesnt heat up.

It has been suggested that maybe the engine water pump isnt pumping the hot engine water around the calorifier at that engine speed ? There are no restrictions or air locks in the system.

I have spoken to others who dont seem to have a problem at battery charge engine speed so I'm lost as to what it might be.

Has anyone any ideas how I might cure this please.

Thanks everyone

JULES

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If the engine is not running hot enough to open up the thermostat the flow of heating water through the calorifier may be negligible.

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Hi MartynG

Thanks for your advice I know the thermstat is a genuine replacement but I do see what your suggesting and you may be right at that.

JULES

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You should be able to buy a replacement thermostat that opens at a lower temp fairly cheaply to test that theory. You'll obviously need to find out what thermostat you've already got first.

Edited by blackrose

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Whats the engine make & model?

I have a vetus, which didn't heat up, the thermostat had fallen over in the hose!  allowing cold water from the skin tank to flow around the engine unhindered.

Mariniser had moved the thermostat from the normal expected housing, to the top hose to allow calorifier connections to use hot engine coolant, before the thermostat.

 

Bod

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The take off point for the water to the calorifier should be before the thermostat. On a marinised vehicle engine it usually uses what would have been the heater connection. Check on your engine where the connection is made if after the thermostat it has been incorrectly installed. The calorifier should get water hot before the thermostat opens. On our boat 30mins running at idle speeds gives us plenty of hot water.

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28 minutes ago, MartynG said:

If the engine is not running hot enough to open up the thermostat the flow of heating water through the calorifier may be negligible.

That very much depends on the engine. I would say the majority of engines will send far more water through the calorifier circuit with the thermostat closed than when its open. The exceptions are those like the Shire ranger that have a separate calorifier thermostat.

 

As Bod asks make and model of engine.

 

At 900 rpm it will take ages for the engine  to come up to temperature, especially if it is also heating a clarifier so there may be nothing wrong with it AND it is engine abuse to run at idle or just above for long periods, especially when battery charging. Engines, especially diesels get on better when they are under load.

 

For battery charging run at whatever speed gives you the maximum charging current, this could start at 2000 rpm. Then as the batteries charge and the current reduces slow the engine (to economise on fuel) so the speed is still giving the maximum output the batteries will accept. I tend to run at 1000 to 1500 rpm for such things.

Just now, Richard T said:

The take off point for the water to the calorifier should be before the thermostat. On a marinised vehicle engine it usually uses what would have been the heater connection. Check on your engine where the connection is made if after the thermostat it has been incorrectly installed. The calorifier should get water hot before the thermostat opens. On our boat 30mins running at idle speeds gives us plenty of hot water.

Not necessarily true, A Shire won't, they get the engine up to temperature first and I think some marine conversions of "vintage" engines may do the same..

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20 minutes ago, bargebird said:

Hi blackrose & Bod

I have an 82 degree genuine Isuzu thermostat fitted and its an Isuzu 55.

 

JULES

Have you checked that the waterpump drive belt is correctly tensioned and in good condition ?

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Thanks for the replies so far. I will try and check on connections tomorrow.

Any further ideas will be welcomed.

Many thanks

 

JULES

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Diesel engines need to work to produce heat. I used to have a Nanni/kubota that heated the water perfectly when boating it took hours when moored. Nothing wrong its just physics ;)

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If you can be arsed, trace out the water/cooling circuit and post in here. That is if you want direct focussed help.

Edited by mark99

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11 hours ago, bargebird said:

Hi blackrose & Bod

I have an 82 degree genuine Isuzu thermostat fitted and its an Isuzu 55.

 

JULES

I think that engine will start to warm the calorifier circuit from the moment it starts band long before the thermostat opens to allow the bulk of the coolant to flow into the skin tank The calorifier feed pipe that comes from high up on the engine (not the one that is usually Td into the return pipe/hos to the engine water pump) should start to get warm (by no mean shot) within 10 minutes or so of starting. The other lower down calorifier pipe will stay cold at that time because most of the heat will be given up to the domestic water. This applies whichever way round the calorifier is piped. If this does not happen and the top pipe never heats really hot really close to the engine then I suspect an air lock. If its a vertical calorifier there is every chance the top connection is higher than the engine and I would be tempted to fit a bleed valve at the highest point on that hose/pipe.

 

However before doing too much more try running at 1500 rpm in neutral and see if it helps.

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One thing that is not clear to me is how long are you leaving the engine running and expecting hot water?  I would leave the engine running at 1200rpm and every 20mins run the hot tap for (say) 30 secs so you know water from the calorifier has arrived and it should a bit hotter each time.  My beta engine with a large calorifier takes about an hour for warm water and about 2 hours for hot.  If the hot water has not become at least Luke warm within an hour then there is no flow from the engine.

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I could never get my cauliflower to heat up when static -

UNTIL I fitted a header tank as high as I could - since then no problems, though if I want some hot water / heating in a reasonable time, then I use the Ebersplutter.  

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The difference between engines as regards flow to a calorifier seems to be where the hot water take off the engine is located with respect to the thermostat.

The engines where the take off is on the rear of the cylinder head seem to do better, as far away from the thermostat as possible.

Its vital to get all the air out of the flow and return pipes, an air bubble will reduce or stop the flow instantly. The current use of plastic pipes  which sag between clips causes air locks, its better if they are clipped on the top of a rigid batten with a constant rise to the air discharge point, preferably an open header tank.

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Guest
18 hours ago, Tony Brooks said:

That very much depends on the engine. I would say the majority of engines will send far more water through the calorifier circuit with the thermostat closed than when its open. The exceptions are those like the Shire ranger that have a separate calorifier thermostat.

 

As Bod asks make and model of engine.

 

At 900 rpm it will take ages for the engine  to come up to temperature, especially if it is also heating a clarifier so there may be nothing wrong with it AND it is engine abuse to run at idle or just above for long periods, especially when battery charging. Engines, especially diesels get on better when they are under load.

 

For battery charging run at whatever speed gives you the maximum charging current, this could start at 2000 rpm. Then as the batteries charge and the current reduces slow the engine (to economise on fuel) so the speed is still giving the maximum output the batteries will accept. I tend to run at 1000 to 1500 rpm for such things.

Not necessarily true, A Shire won't, they get the engine up to temperature first and I think some marine conversions of "vintage" engines may do the same..

Thtat is what we have found after nearly 15 years of Vetus ownership.

Edited by Guest

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The above posts seem to cover things, but when it's sorted consider putting a temperature gauge on the carolifier.  I have a cheap gauge off eBay described as an aquarium gauge. It's great for deciding if engine needs to be run before you can have a shower! :-)

Just tape the sensor as close to the carolifier outlet as possible.

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38 minutes ago, Floating Male said:

The above posts seem to cover things, but when it's sorted consider putting a temperature gauge on the carolifier.  I have a cheap gauge off eBay described as an aquarium gauge. It's great for deciding if engine needs to be run before you can have a shower! ?

Just tape the sensor as close to the carolifier outlet as possible.

I just turn a tap on to see if hot water comes out.

  • Greenie 1

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has your engine control panel got a temp gauge on it? if so does the engine actually get fully warm when running at tick over. My izusu 43 runs at 65 degrees on prolonged tick over(600rpm) and would take ages to get the water tank hot, when cruising(1200rpm) it runs about 80-95 degrees and takes the best part of an hour to get a tank full of hot water.

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Hi everyone

I tried your suggestions and ran the engine at 1100rpm checking both calorifier hoses for heat and after 90mins running the water is hot so it was just me not running the engine fast enough.

Many thanks for ALL your suggestions it seems I keep learning all the time ?

 

JULES

  • Greenie 1

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Guest
38 minutes ago, bargebird said:

Hi everyone

I tried your suggestions and ran the engine at 1100rpm checking both calorifier hoses for heat and after 90mins running the water is hot so it was just me not running the engine fast enough.

Many thanks for ALL your suggestions it seems I keep learning all the time ?

 

JULES

Possibly your batteries will get a better charge too. 
We are all learning all of the time.

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