Hot water from raw water cooled engine

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headrowe

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Hi, Iwas wondering if anybody has ever linked up a calorifier to a raw water cooled engine? I have twin Volvo MD17D raw water cooled engines and was hoping to run my domestic hot water from one. I know the temperature would be lower than an indirect system but would it be hot enough and would there be any problems with the circulation in view of the system relying on the external raw water pump only
I would be grateful for any advice on this topic or any other suggestions. My aim is to eliminate the gas fuelled Paloma heater situated in the shower compartment.
Thanks in advance.
 
Our 2GM20 is raw water cooled and runs the calorifier .. it takes the feed inbetween the output from the engine and the inject into the exhaust.
It isn't very warm though (replacement thermostat on the way!)
 
I've been wondering about doing this. Does anyone know whether a standard marine calorifier can take hot salt water (fitted with a stainless worm, presumably) or does it need to be specially made?
 
Reading about this elsewhere, there seems to be some with raw water cooling who get their water hot enough and those who don't. For the Volvo 2003 there is a conversion kit to indirect engine cooling via a heat exchanger. May be expensive but will undoubtedly get you hot water.
 
Hi,

Have PM'd (private messaged) you. In case you haven't used this before, just click on 'User options' at the top of the page, then on 'Received Private Messages'.

Cheers Jerry
 
Yes, you can use a copper calorifier perfectly well. The one in my raw-water engined boat is now 23 years old and is still in perfect condition. Oh Lord, watch it blow up now or sumfing!!!! /forums/images/graemlins/frown.gif /forums/images/graemlins/frown.gif

Don't remember seeing one with a s/s coil but no doubt someone will be along to prove me wrong!
 
I fitted a standard calorifier to my previous boat (Feeling 346) which had a Volvo Penta 2003 with raw water cooling. I don't remember the make of the calorifier but it was definitely not SS. I remember we had to cut into a water pipe on top of the engine and we fitted three standard plumbing shut off valves (screw driver type) so we could isolate the calorifier if we had a problem. It was quite a neat install and the water was plenty hot enough.

Dave
 
Hi, thanks for your reply. You say your water is not very warm! Jerryat has messaged me and says this is usually the case but if you fit a constantly running pump in either the flow or exhaust side of thsystem your water will be much hotter! Maybe it's not the thermostat?
 
Tee hee! I like the idea of using a B and Q version!! I stand to be corrected, but I suspect that they wouldn't do one small enough for the average boat - but then you may not have a 'small' boat!

In any case, the 'hose' connections would be far larger than than necessary and maybe even unusable. Someone here may know better but I don't think it's a starter.
 
I HAVE RECENTLY FITTED AN "ISOTEMP WATER CALORIFIER" IN MY BOAT, IT SEEMS EXCELLENT, IN THE BUMPH IT SAYS IT CAN BE USED WITH A RAW WATER COOLED ENGINE, IT HAS A STAINLESS TANK AND COIL, I WOULD BE A BIT WORRIED ABOUT COPPER. THE ISOTEMP HAD A GOOD WRITE UP IN A YM REPORT. I BOUGHT THE SQ ONE AND IT GIVES PLENTY OF WATER FOR TWO SHOWERS.
 
This is an interesting topic for me too, having a Perkins 4.108 with raw cooling and, when i fitted my calorifier, i just assumed it wasn't possible to make use of the cooling water. Time for a rethink me thinks.

I also have problems getting the engine up to opperating temperatures too. Could rerouting the cooling water through the calorifier help at all with this?
 
Just a thought, I had a 4.107 in an older boat, direct cooling and it too never reached operating temperature when we first got it. Having delved into it's innards discovered a dodgy stat, swopped that over, changed over the temp gauge sensor (they seem to "fur" up) hey presto reached operating temp, excess water injected into the exhaust via the by-pass.

So for hot water, wouldn't you need to tap into the block? My Thorneycroft has spare tappings plugged off in the head. As the water at these points would be at operating temp wouldn't the engine circulation pump send hot water thro' your calorifier. Assumes you have tappings of course, but as many marine engines are basicly adapted road vehicle engines and all of those have heaters???????

Clearly you don't want to try to heat a calorifier with the by-pass water as it probably doesn't get very hot, you need to get it from the engine side of the stat somehow.
 
Ours is definately a thermostat problem ... had it out and apart last year, quick clean up and pop back in ... but wasn't good even then - I'll bung a new one in first then diagnose any further problems.

We did have hot water via this system - so it can only be the thermostat that has b&ggered up.
 
Thinking along same lines, remembered alternative mag. article. They, with assistance from Lancing Marine, removed the temp sender, fitted "T" for sender and tapping. The other connection, same set up at engine block drain. Permanent pump connected to ignition. No mention of temp or control, but stat connected to pump should stop overheating.
 
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