Perkins mc42 heat exchanger

[patrickr]

Good evening. I am new to this world so I hope this is not a daft question.I am in the process of putting anti freeze in my engines cooling system, which is a closed sytem with a side tank in the stern the engine is a perkins mc42 and it also has a heat exchanger sorrounding the exhaust manifold, which supplies hot water to the boats heating sytem and hot water tank. My question is . Is the heat exchanger water all connected togethter in the exchanger so that the antifreeze will go into the boats heating sytem as well as the engine cooling syetm , or are they seperate . If they are seperate do people put anti freeze in their internal boat heating sytems for the winter and if so what do they use. Tahnks Patr

[jelunga]

I can see nothing against putting antifreeze in the system. My boat (well soon to be my boat) has an Eberspacher boiler, which provides hot water through the calorifier and also heats radiators around the boat. Eberspacher recommends 40 % anti freeze. The engine's cooling circuit will, i fitted, also heat the hot water via a calorifier coil. This will no doubt be the cooling circuit also. it should have antifreeze in, not only to prevent the circuit freezing, but also as an anticorrosive medium.

 

K

 

Good evening. I am new to this world so I hope this is not a daft question.I am in the process of putting anti freeze in my engines cooling system, which is a closed sytem with a side tank in the stern the engine is a perkins mc42 and it also has a heat exchanger sorrounding the exhaust manifold, which supplies hot water to the boats heating sytem and hot water tank. My question is . Is the heat exchanger water all connected togethter in the exchanger so that the antifreeze will go into the boats heating sytem as well as the engine cooling syetm , or are they seperate . If they are seperate do people put anti freeze in their internal boat heating sytems for the winter and if so what do they use. Tahnks Patr

[Keeping Up]

Good evening Patr and welcome.

 

As an MC42 owner and devotee I hope I can answer your question.

 

The usual setup is that the engine cooling system includes the engine itself, the manifold water-jacket, the skin tank, possibly an oil-cooler for the gearbox, and a pair of pipes which take some of the hot water and pass it through a coil in a calorifier tank. The pressure cap is normally on the top of the manifold jacket. All of these share the same water/antifreeze mixture, so if you add antifreeze through the top of the manifold jacket (or, if there is one, to the additional header tank that connects into the top of it) that antifreeze will protect all those components assuming it has been properly circulated through the system.

 

The calorifier tank itself is filled with water from the boat's fresh water system (which does not of course want antifreeze in it); the heating coil which is fed from the engine transfers heat to it but keeps the water systems separate. This gives you the hot water for the taps. It would be very unusual for the boat's heating system to be run directly from the engine - although of course anything is possible - and it would be normal for it to be heated by either a boiler (gas, diesel, or solid-fuel powered). As such the heating system would need to be protected by a separate infusion of antifreeze.

 

It is also normal that the boiler which heats the radiators, if it is either gas or diesel, to heat also the hot water by means of a second coil in the calorifier. This doesn't make any difference to the antifreeze situation. Where the calorifier does have two coils in this way you can get a smaller amount of heat into the radiators by switching on the circulation pump without the boiler. The engine heats the first coil which heats the water in the calorifier tank which heats the second coil which passes some heat to the radiators. Is this perhaps why you state that the engine heats both the hot water and the heating system, or does the boat have an unusual and possibly unique setup of some type?

[patrickr]

Good evening Patr and welcome.

 

As an MC42 owner and devotee I hope I can answer your question.

 

The usual setup is that the engine cooling system includes the engine itself, the manifold water-jacket, the skin tank, possibly an oil-cooler for the gearbox, and a pair of pipes which take some of the hot water and pass it through a coil in a calorifier tank. The pressure cap is normally on the top of the manifold jacket. All of these share the same water/antifreeze mixture, so if you add antifreeze through the top of the manifold jacket (or, if there is one, to the additional header tank that connects into the top of it) that antifreeze will protect all those components assuming it has been properly circulated through the system.

 

The calorifier tank itself is filled with water from the boat's fresh water system (which does not of course want antifreeze in it); the heating coil which is fed from the engine transfers heat to it but keeps the water systems separate. This gives you the hot water for the taps. It would be very unusual for the boat's heating system to be run directly from the engine - although of course anything is possible - and it would be normal for it to be heated by either a boiler (gas, diesel, or solid-fuel powered). As such the heating system would need to be protected by a separate infusion of antifreeze.

 

It is also normal that the boiler which heats the radiators, if it is either gas or diesel, to heat also the hot water by means of a second coil in the calorifier. This doesn't make any difference to the antifreeze situation. Where the calorifier does have two coils in this way you can get a smaller amount of heat into the radiators by switching on the circulation pump without the boiler. The engine heats the first coil which heats the water in the calorifier tank which heats the second coil which passes some heat to the radiators. Is this perhaps why you state that the engine heats both the hot water and the heating system, or does the boat have an unusual and possibly unique setup of some type?

 

 

Many thanks for this, it clears up most of my questions. I may well have it wrong in assuming the radiators recieve heat from the engine. I have a solid fuel stove that also heats radiators, I think I assumed that the engine heated them as well. So that leaves me two questions. The first is roughly how much anti freeze will I need, the set up is as you describe, from the engine manual it would be about 4 litres of antifreeze, but I doubt that applies to the tanks and pipes in the boat, a rough guide will do. secondlyhow do I get antifreeze or failing that inhibitor into a squirrel stove central heating system ? or is it not necessary unless very cold weather comes. I assume that what you all call a calorifier is what looks like a hot water tank in the shower room. Thanks Pat

[Keeping Up]

Many thanks for this, it clears up most of my questions. I may well have it wrong in assuming the radiators recieve heat from the engine. I have a solid fuel stove that also heats radiators, I think I assumed that the engine heated them as well. So that leaves me two questions. The first is roughly how much anti freeze will I need, the set up is as you describe, from the engine manual it would be about 4 litres of antifreeze, but I doubt that applies to the tanks and pipes in the boat, a rough guide will do. secondlyhow do I get antifreeze or failing that inhibitor into a squirrel stove central heating system ? or is it not necessary unless very cold weather comes. I assume that what you all call a calorifier is what looks like a hot water tank in the shower room. Thanks Pat

First the easy one: yes the calorifier is the thing that looks like a hot water tank and it may well be in the shower room (not having seen your boat I can't tell if it's the shower room or not )

 

The next easy one, yes you do need antifreeze in the central heating system, even when it is driven by a Squirrel. There should be a header tank somewhere, that you can top up; it could be anywhere, so you'll just have to search for it. The only clues I can give you are (1) it will be higher up than the top of the stove or any of the radiators and (2) it is connected to the pipework somewhere. OK they're pretty obvious clues, I know, but from there onwards you're on your own! When you've found it, the way to get antifreeze in is first to drain some (or all) of the water, usually at a radiator, then pre-mix some water and antifreeze and add it to the header tank; of course you need to ensure it gets mixed in by perhaps daraining some more so it runs out of the header tank, then by running the system.

 

You don't of course need antifreeze until the cold weather comes - but the "morning after" could be too late. Also you should use conventional antifreeze just like the type you put in a car, and that includes an inhibitor so it's best to put it in anyway.

 

Now for quantities. Difficult. You'll need more than 4 litres, that's for sure. The engine manual won't include the pipework, as you say, but the pipes aren't going to hold a lot. But before you breathe too big a sigh of relief, the skin tank is likely to hold at least as much as the engine. And as for the heating system, well that's anybody's guess. You could perhaps estimate it by finding out the capacity of the radiators and work from there.

 

Personally, particularly as you don't know what if anything is in there already and how long it has/hasn't been there would be to drain everything - engine, skin tank radiators, the lot - and see how much comes out, then refill it as appropriate. As for how to do all that, it's a long story, so can you do it OK?

[steelaway]

Many thanks for this, it clears up most of my questions. I may well have it wrong in assuming the radiators recieve heat from the engine. I have a solid fuel stove that also heats radiators, I think I assumed that the engine heated them as well. So that leaves me two questions. The first is roughly how much anti freeze will I need, the set up is as you describe, from the engine manual it would be about 4 litres of antifreeze, but I doubt that applies to the tanks and pipes in the boat, a rough guide will do. secondlyhow do I get antifreeze or failing that inhibitor into a squirrel stove central heating system ? or is it not necessary unless very cold weather comes. I assume that what you all call a calorifier is what looks like a hot water tank in the shower room. Thanks Pat

 

 

Hi

 

I think you should mix up 5 gallons at 25-40% antifreeze and keep pouring it in 'till it's full

If you mix too much you can save it for 'top ups'

 

Alex

[WotEver]

... the way to get antifreeze in is first to drain some (or all) of the water, usually at a radiator, then pre-mix some water and antifreeze and add it to the header tank...

I just wanted to point out that it's essential that you follow Allan's advice here. Don't be tempted to just drain out say a gallon of water and put a gallon of anti-freeze in expecting it all to mix automatically. It almost certainly wouldn't.

 

Tony

[RLWP]

I just wanted to point out that it's essential that you follow Allan's advice here. Don't be tempted to just drain out say a gallon of water and put a gallon of anti-freeze in expecting it all to mix automatically. It almost certainly wouldn't.

 

Tony

 

Now, I know that advice is true for gravity fed central heating, but in a boat engine with a pump, it's going to mix when the engine runs. So run the engine when you have put the anti-freeze in. You should to drive air out anyway.

 

Richard

[WotEver]

Now, I know that advice is true for gravity fed central heating, but in a boat engine with a pump, it's going to mix when the engine runs. So run the engine when you have put the anti-freeze in. You should to drive air out anyway.

 

Richard

But that advice was with relevance to the solid fuel stove fed radiators, not the engine coolant.

[RLWP]

But that advice was with relevance to the solid fuel stove fed radiators, not the engine coolant.

 

My mistake. Sorry.

 

Richard

[Johnboy70]

Good evening Patr and welcome.

 

As an MC42 owner and devotee I hope I can answer your question.

 

The usual setup is that the engine cooling system includes the engine itself, the manifold water-jacket, the skin tank, possibly an oil-cooler for the gearbox, and a pair of pipes which take some of the hot water and pass it through a coil in a calorifier tank. The pressure cap is normally on the top of the manifold jacket. All of these share the same water/antifreeze mixture, so if you add antifreeze through the top of the manifold jacket (or, if there is one, to the additional header tank that connects into the top of it) that antifreeze will protect all those components assuming it has been properly circulated through the system.

 

The calorifier tank itself is filled with water from the boat's fresh water system (which does not of course want antifreeze in it); the heating coil which is fed from the engine transfers heat to it but keeps the water systems separate. This gives you the hot water for the taps. It would be very unusual for the boat's heating system to be run directly from the engine - although of course anything is possible - and it would be normal for it to be heated by either a boiler (gas, diesel, or solid-fuel powered). As such the heating system would need to be protected by a separate infusion of antifreeze.

 

It is also normal that the boiler which heats the radiators, if it is either gas or diesel, to heat also the hot water by means of a second coil in the calorifier. This doesn't make any difference to the antifreeze situation. Where the calorifier does have two coils in this way you can get a smaller amount of heat into the radiators by switching on the circulation pump without the boiler. The engine heats the first coil which heats the water in the calorifier tank which heats the second coil which passes some heat to the radiators. Is this perhaps why you state that the engine heats both the hot water and the heating system, or does the boat have an unusual and possibly unique setup of some type?

[Johnboy70]

Can i quiz you on my MC42 cooling issue as you seem to be a guru on the said beast.

 

The outlet from the header tank to the skin tank gradually warms up. Is this correct or should it get hot quickly as the stat opens as i have seen in other boats? Changed the stat a while back but i'm not entirely sure i put it back into it's housing the right way round, should it go big spring facing out or inwards. Anyway the problem was the same before i changed it. Also if i go on a long cruise eventually the engine over heats and blows out coolant into the bilge. Was wondering if the head gasket was leaking and blowing the coolant out or there might be a blockage in the system somewhere which could be flushed. Engine smokes a bit when it's cold. Any thoughts most welcome. Cheers.

[Keeping Up]

I've never checked how quickly the pipe between the header tank and the skin tank warms up, but I would have expected it to remain cool until the stat begins to open and then to warm up fairly quickly. And sorry I can't remember which way up the stat fits.

 

I would suspect that a blockage is making it overheat. I know that mine will blow coolant out if it gets blocked; A couple of years ago the area around my stat got blocked with rubber debris from elderly hoses and I would lose about a pint or two of water every day which then led to the engine overheating and blowing the rest out.

 

What colour is the smoke when cold? White smoke might suggest a head gasket problem, blue or black would not.

[Tony Brooks]

Can i quiz you on my MC42 cooling issue as you seem to be a guru on the said beast.

 

The outlet from the header tank to the skin tank gradually warms up. Is this correct or should it get hot quickly as the stat opens as i have seen in other boats? Changed the stat a while back but i'm not entirely sure i put it back into it's housing the right way round, should it go big spring facing out or inwards. Anyway the problem was the same before i changed it. Also if i go on a long cruise eventually the engine over heats and blows out coolant into the bilge. Was wondering if the head gasket was leaking and blowing the coolant out or there might be a blockage in the system somewhere which could be flushed. Engine smokes a bit when it's cold. Any thoughts most welcome. Cheers.

 

 

The big spring as you call it normally fits pointing into the engine. If you look inside the spring you should see the small brass or copper "cylinder" that contains the copper/wax capsule. This has to be in the hot part of the engine so the stats will open. If you managed to fit it upside down (and on many engines that is not possible) I would expect boiling, not a slow warm up.

 

Many stats have a small air bleed hole in the lip and I doubt that many bare absolutely watertight when closed so you will always get a small amount of water leaking past the thermostat. This may well heat the pipework & outlet up slowly. Even when the stats opens it does not open fully. It will open a a certain amount, then as the colder water is circulated back into the engine it is likely to close either full or partially until the water in the engine is heated again.

 

Then if the boat has a calorifier fitted that will usually extend the warm up time.

 

On the face of it you seem to be trying to cure a non-fault.