Thermostats & calorifiers etc.

stuhaynes

stuhaynes

Well-Known Member
Joined
25 Dec 2009
Messages
707
Location
Yorkshire
www.best-camping-stoves.com
Now celebrating! :D:D. Calorifier hooked up and working!

I want to isolate the calorifier when it gets up to temperature and propose using a thermostat to do that, one that closes when the calorifier is up to temperature, as opposed to a car type that opens at a pre-determined temperature. Anyone know of a beast like this that does not require mains power to operate? We're 24 volts by the way.

We haven't given the setup a run yet under load, and isolation may not be necessary, but if it is needed it would be handy to be prepared.
 
As far as I know my calorifier has no shut-off thermostat and I frankly do not see the benefit of one. Once your engine has reached its working temperature, there is no risk of overheating your calorifier, and I do not think that it will matter much whether your engine has to pump the water through the calorifier or not. Unless there are finer points that I am not aware of, which is perfectly possible...:)
 
Calorifier limit temp

Forgive me if I am teaching my grandmother but I imagine that you want to limit the calorifier temperature to avoid having scalding hot water from the tap as we had on our Westerly.
Our newer boat has a thermostatic mixer at the calorifier so that as hot water is drawn off it is mixed with cold so as to limit the temperature, this probably makes the hot water go further as well although I am not totally convinced.
I don't know but are all newer boats fitted with these? (I know a Halberg of the same age did not)
See
http://www.quickitaly.com/?lng=us&ms1=10&ms2=11&ms3=46&ctm=0&cs1=1&cs2=1
 
Last edited:
A "cylinder stat" is what you are looking for. It looks like a household radiator thermostat but has an external sensor which is lashed to whatever you want to monitor but also has an internal sensor which might be enough for your application. The temperature is fully adjustable and it needs no electrical connections. There are many brands on sale but probably the most reliable is this one, made by Drayton, called a "Tapstat:-

18a49342-02fe-402d-aa92-4780bd15e9af.jpg


The diverting one in the middle would be the best choice
.

Incidentally, I am curious as to your reasons for wanting a lower temperature in your calorifier than the 83C which is engine temp. Is it for child safety? Most want the largest quantity of hot water and are content to dilute it with cold in a mixer tap to get enough water for showers for the whole crew.

Chas
 
Last edited:
KellysEye said:
All calorifiers come with a thermostat set at 70 degree C to stop legionnaires disease. If the temperature goes higher than that then the thermostat is broken.
Click to expand...

I think you will find it's the other way around. Temperatures above 70C fully disinfect systems contaminated with legionella. Below 70C the bacteria can survive. See http://en.wikipedia.org/wiki/Legionellosis

None of the calorifiers I have owned had a thermostast.
 
Fitting a thermostat between the engine and the calorifier may create engine problems.

On my engine the calorifier feed and return are connected to the engine either side of the engine thermostat thus acting as a bypass when the engine is cold.

My engine manual states that the bypass must NEVER be shut off. So water must always be allowed to flow through the calorifier. Therefore on my setup a calorifier thermostat is a definite no-no.
 
harstonwood said:
What happens on shore power? Does it rely on the pressure relief valve?
Click to expand...

When it is on shorepower the water is heated by an immersion heater,[electric element] this is controlled by a thermostat.

I believe the OP is referring to the water that passes through through a coil inside the calorifier, this water is heated by the engine and he wishes to control this by another thermostat.
 
theoldsalt said:
Fitting a thermostat between the engine and the calorifier may create engine problems.

On my engine the calorifier feed and return are connected to the engine either side of the engine thermostat thus acting as a bypass when the engine is cold.

My engine manual states that the bypass must NEVER be shut off. So water must always be allowed to flow through the calorifier. Therefore on my setup a calorifier thermostat is a definite no-no.
Click to expand...

Which is why I recommended that he choose the "By-pass" option in my post. Don't you tread other people's responses before posting?

Chas
 
theoldsalt said:
Fitting a thermostat between the engine and the calorifier may create engine problems.

On my engine the calorifier feed and return are connected to the engine either side of the engine thermostat thus acting as a bypass when the engine is cold.

My engine manual states that the bypass must NEVER be shut off. So water must always be allowed to flow through the calorifier. Therefore on my setup a calorifier thermostat is a definite no-no.
Click to expand...

AGAIN: this is why I recommended the "By-pass" option in my recommendation. DO try to keep up!

Chas
 
CharlesSwallow said:
A "cylinder stat" is what you are looking for. It looks like a household radiator thermostat but has an external sensor which is lashed to whatever you want to monitor but also has an internal sensor which might be enough for your application. The temperature is fully adjustable and it needs no electrical connections. There are many brands on sale but probably the most reliable is this one, made by Drayton, called a "Tapstat:-

18a49342-02fe-402d-aa92-4780bd15e9af.jpg


The diverting one in the middle would be the best choice
.

Incidentally, I am curious as to your reasons for wanting a lower temperature in your calorifier than the 83C which is engine temp. Is it for child safety? Most want the largest quantity of hot water and are content to dilute it with cold in a mixer tap to get enough water for showers for the whole crew.

Chas
Click to expand...


To be perfectly honest the reason I thought of isolating the calorifier is because I wanted to maximise the water going through the heat exchanger when the calorifier was up to temperature.

This coming week will tell me whether I need to add a tank isolator as we're away for a few days. I can't really see the cooling system will be a problem but as I am diverting some of the sealed system water away from the raw water heat exchanger I thought it may be a possibility. It's one of those things that I have to get my head around. :confused:


Edited to add: Our engine is more than 60 years old and there never has been the option of an engine thermostat. When running at a river cruising speed of 1600 RPM our temperature guage reads 160F. At lower engine speeds the temperature reads about 140F. By using a stat that cuts the supply off at 160F our hot water supply will go further. As already stated, we're away next week and so will be able to do a 'working' test of whether we need to modify the set up or not.
 
Last edited:
CharlesSwallow,

Yes I did read your post 5, and I do try to keep up. There was no mention of hazard to an engine or reasons for your advise.

I was merely trying to be helpful to the OP and the forum in general by giving my experience even if not applicable in the OP's curcumstances.

Thank you for taking the trouble to use two posts to be critical of someone trying to be helpful.

Perhaps in future you could explain the reasons for your advise so that we can understand them a little more.
 
theoldsalt said:
CharlesSwallow,

Yes I did read your post 5, and I do try to keep up. There was no mention of hazard to an engine or reasons for your advise.

I was merely trying to be helpful to the OP and the forum in general by giving my experience even if not applicable in the OP's curcumstances.

Thank you for taking the trouble to use two posts to be critical of someone trying to be helpful.

Perhaps in future you could explain the reasons for your advise so that we can understand them a little more.
Click to expand...

Thank you Old Salt

I'm in a bit of 'no mans land' at the moment. I've interfered with the cooling system, I've nicked some hot water. When the HW tank has had its fill I'm pretty sure that the Jabsco will be man enough to deal with the detour I've put in the line. (says he biting finger nails!!) We're off tomorrow, no timetable, but off for up to a week or so. In more modern boats this has all been taken care of. We're sort of flying by the seat of our pants. (Fingers crossed) The old girl will cope, and with a bit of luck the engine will be okay too! Kath will kill me if she reads this....... :p
 
theoldsalt said:
CharlesSwallow,

Yes I did read your post 5, and I do try to keep up. There was no mention of hazard to an engine or reasons for your advise.

I was merely trying to be helpful to the OP and the forum in general by giving my experience even if not applicable in the OP's curcumstances.

Thank you for taking the trouble to use two posts to be critical of someone trying to be helpful.

Perhaps in future you could explain the reasons for your advise so that we can understand them a little more.
Click to expand...

Sorry that you were offended.

Chas
 
stuhaynes said:
To be perfectly honest the reason I thought of isolating the calorifier is because I wanted to maximise the water going through the heat exchanger when the calorifier was up to temperature.

This coming week will tell me whether I need to add a tank isolator as we're away for a few days. I can't really see the cooling system will be a problem but as I am diverting some of the sealed system water away from the raw water heat exchanger I thought it may be a possibility. It's one of those things that I have to get my head around. :confused:


Edited to add: Our engine is more than 60 years old and there never has been the option of an engine thermostat. When running at a river cruising speed of 1600 RPM our temperature guage reads 160F. At lower engine speeds the temperature reads about 140F. By using a stat that cuts the supply off at 160F our hot water supply will go further. As already stated, we're away next week and so will be able to do a 'working' test of whether we need to modify the set up or not.
Click to expand...

What is your engine? Are you sure that there is no thermostat in the fresh water circuit somewhere? Even in the 50s they were usually fitted. Has it perhaps been removed by a previous owner. If there were a thermostat this would solve your problem of the engine running too cool. Can you post a picture of the joint where the water comes out of the cylinder head?

Chas
 
Yon engine temps are very high if measured from the closed water side. I would suspect raw water cooling system need attention !!!
 
You must log in or register to reply here.

Share this page

Top