chouchou
Member
I have a Sun Odyssey 29.2 and want be able to provide hot water and heating for winter sailing. The engine (Yanmar 20GM) is cooled directly so not sure if a heat exchanger for hot water will work. Any advise appreciated.
HEATING/HOT WATER
- Thread starter chouchou
- Start date
Robin2
Well-Known Member
I presume you mean a 2GM (16hp) engine. If it is not fresh water cooled the water temperature will not be high enough for hot water or heating.
jerryat
Well-Known Member
I don't agree with you. Unless the engine you refer to is very unusual or has a faulty thermostat you will get excellent hot water via a calorifier. I agree that the engine water temp won't be as high as for a fresh-water cooled motor, but it is more than good enough for use in a hot water system.
With mine you certainly couldn't keep your hand in what pours into our sinks/shower without adding cold water that's for sure!!!
With mine you certainly couldn't keep your hand in what pours into our sinks/shower without adding cold water that's for sure!!!
NealB
Well-Known Member
I\'ll second Jerry on this one...nm
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TheBoatman
Well-Known Member
It can be done but the system is not very efficient unless the engine is run under load for a relatively long period.
This is how you should go about it.
On the front of your engine you will see the thermostat housing ~ it will have 2 water pipes connected to it ~ 1 coming from the bottom of the engine the other going to the exhaust elbow.
You need to replace the pipe heading for the exhaust and pipe that to the inlet of your tank ~ the exit from the tank goes to the exhaust elbow.
Best of luck ~ it will work and give you hot water, it's just a bit slower than the freshwater systems.
Peter.
This is how you should go about it.
On the front of your engine you will see the thermostat housing ~ it will have 2 water pipes connected to it ~ 1 coming from the bottom of the engine the other going to the exhaust elbow.
You need to replace the pipe heading for the exhaust and pipe that to the inlet of your tank ~ the exit from the tank goes to the exhaust elbow.
Best of luck ~ it will work and give you hot water, it's just a bit slower than the freshwater systems.
Peter.
jerryat
Well-Known Member
Thanks Boatman, but I installed my current system many years ago and it has performed perfectly ever since - including almost ten years full time cruising!
Perhaps your comment was not for me?
I have also installed several similar complete systems on other boats with, so I am assured, equally good results. There is absolutely NO reason for the hot water to be a 'bit slower', it is simply a matter of installing a pump in the circulating pipework, something incidentally, that would dramatically improve many of the indirect cooled engine systems I've come across.
I assure you and others contemplating an installation, that using a pump such as one from the Johnson range of continuously rated pumps will transform many 'slow to warm-up' systems and provide very hot water even from a raw-water cooled motor. However DO check with your engine manufacturer to ensure that the correct sized pump is chosen.
Perhaps your comment was not for me?
I have also installed several similar complete systems on other boats with, so I am assured, equally good results. There is absolutely NO reason for the hot water to be a 'bit slower', it is simply a matter of installing a pump in the circulating pipework, something incidentally, that would dramatically improve many of the indirect cooled engine systems I've come across.
I assure you and others contemplating an installation, that using a pump such as one from the Johnson range of continuously rated pumps will transform many 'slow to warm-up' systems and provide very hot water even from a raw-water cooled motor. However DO check with your engine manufacturer to ensure that the correct sized pump is chosen.
VicMallows
Well-Known Member
Surely the water flowing to the exhaust elbow is a mix of cold incoming water and just the amount of hot from the engine block necessary to maintain the desired block temperature ?
The usual method as far as I am aware to to tap the calorifier off two connections to the block so that once the engine is warmed up it receives the full temperature.
As Jerry says, it really needs a circulation pump (can be electric), though some people claim to get by with gravity feed.
Vic
The usual method as far as I am aware to to tap the calorifier off two connections to the block so that once the engine is warmed up it receives the full temperature.
As Jerry says, it really needs a circulation pump (can be electric), though some people claim to get by with gravity feed.
Vic
jerryat
Well-Known Member
Chouchou, have PM'd you. In case you don't know, just click on the little flashing flag next to 'User Options' to read it.
TheBoatman
Well-Known Member
Jerry
Sorry they were for the original poster.
Peter.
Sorry they were for the original poster.
Peter.
TheBoatman
Well-Known Member
[ QUOTE ]
The usual method as far as I am aware to to tap the clarifier off two connections to the block so that once the engine is warmed up it receives the full temperature.
[/ QUOTE ]
Agreed but what two connections are you using on a 2GM raw water cooled engine?
As far as I'm aware the raw water cooled 2GM has 1 connection to the block + a bypass and hot water exits the engine at the thermostat.
The system/method I described is one I have seen used but that doesn't mean that it's the only system available.
It seems that other posters have a better way of doing it and I would bow to their method if it proved better than mine.
Peter.
The usual method as far as I am aware to to tap the clarifier off two connections to the block so that once the engine is warmed up it receives the full temperature.
[/ QUOTE ]
Agreed but what two connections are you using on a 2GM raw water cooled engine?
As far as I'm aware the raw water cooled 2GM has 1 connection to the block + a bypass and hot water exits the engine at the thermostat.
The system/method I described is one I have seen used but that doesn't mean that it's the only system available.
It seems that other posters have a better way of doing it and I would bow to their method if it proved better than mine.
Peter.
wotayottie
Well-Known Member
I have a Volvo 2003 raw water cooled engine connected to a calorifier by Moody when first made. The system works poorly because the hot water flow to the calorifier is along approx 15 ft or half inch rubber pipe and because the flow is only the "surplus" cooling water when the engine has warmed enough to begin to open the thermostat. But the same engine in a smaller Moody with shorter pipe runs heats water passably. Neither installation will heat above the 60deg C that the engine thermostat on a raw water cooled engine opens at - but then thats the recommended temperature for the water in your home hot water tank. So its ample is you can ever get it that high.
People say that the answer is a pump, and Sadler yachts used to fit one from new. But I have yet to find an electric pump that is rated for hot salt water - and friends with Sadlers seem to use one that is fresh water only and cough up the money for frequent replacements.
If you also need boat heating then the obvious answer is one of the diesel powered water heaters that can operate like you domestic system. Mikuni make one - I was looking at it at the boat show.
People say that the answer is a pump, and Sadler yachts used to fit one from new. But I have yet to find an electric pump that is rated for hot salt water - and friends with Sadlers seem to use one that is fresh water only and cough up the money for frequent replacements.
If you also need boat heating then the obvious answer is one of the diesel powered water heaters that can operate like you domestic system. Mikuni make one - I was looking at it at the boat show.
jerryat
Well-Known Member
Hi wotayottie,
One of this range will handle salt water with no problems. Have used one for many, many years to pump the calorifier circuit on our boats.
http://www.johnson-pump.com/JPMarine/products/circulation/px/circulation.jpg
The whole range is available from ASAP Supplies.
Hope this helps.
One of this range will handle salt water with no problems. Have used one for many, many years to pump the calorifier circuit on our boats.
http://www.johnson-pump.com/JPMarine/products/circulation/px/circulation.jpg
The whole range is available from ASAP Supplies.
Hope this helps.
headrowe
Active Member
Added a calorifier to one of my Volvo MD17d 36hp engines this year. It was my first posting on the forum and my first reply was from jerryat. Explained everthing I needed to know! Although many people said the temperature would be too low, I have had gallons of HOT water all summer. My advice would be....take jerryats advice!
wotayottie
Well-Known Member
[ QUOTE ]
Hi wotayottie,
One of this range will handle salt water with no problems. Have used one for many, many years to pump the calorifier circuit on our boats.
http://www.johnson-pump.com/JPMarine/products/circulation/px/circulation.jpg
The whole range is available from ASAP Supplies.
Hope this helps.
[/ QUOTE ]
These are the ones my Sadler sailing pal uses and they are not recommended for salt water according to both manufacturer and re-seller. They work for a period, but they dont last apparently
Hi wotayottie,
One of this range will handle salt water with no problems. Have used one for many, many years to pump the calorifier circuit on our boats.
http://www.johnson-pump.com/JPMarine/products/circulation/px/circulation.jpg
The whole range is available from ASAP Supplies.
Hope this helps.
[/ QUOTE ]
These are the ones my Sadler sailing pal uses and they are not recommended for salt water according to both manufacturer and re-seller. They work for a period, but they dont last apparently
TheBoatman
Well-Known Member
Forgive me guys but we seem to be suffering from thread drift here.
The original poster quoted a particular engine type and model and asked how it could be piped for hot water.
Whether the pumps work/don't work nobody seems to say were you can connect it to the engine.
Peter.
The original poster quoted a particular engine type and model and asked how it could be piped for hot water.
Whether the pumps work/don't work nobody seems to say were you can connect it to the engine.
Peter.
jerryat
Well-Known Member
HI,
Well I can only speak from personal experience (and those of my friends who use these pumps) and can absolutely assure you that they will last a hell of a long time.
For example, I have owned my boat for about 19 years and have only changed the Johnson pump once (last year!) in that time. That also includes giving it a LOT of use while full time cruising. If you have a look at the specs for these pumps (and the price!!!) you'll see why!!
I've no connection etc except as a somewhat amazed and grateful user.
Well I can only speak from personal experience (and those of my friends who use these pumps) and can absolutely assure you that they will last a hell of a long time.
For example, I have owned my boat for about 19 years and have only changed the Johnson pump once (last year!) in that time. That also includes giving it a LOT of use while full time cruising. If you have a look at the specs for these pumps (and the price!!!) you'll see why!!
I've no connection etc except as a somewhat amazed and grateful user.