Calorifier connections

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Graham_Wright

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I read a magazine response to a question concerning bleeding a horizontal calorifier advising that the hot water take-off pipe at the top of the calorifier was bent upwards within the cylinder ensuring the minimum air space above. As cold water entered the bottom, air would be expelled from the hot water take off until the water level reached the top of the bend.

My Surecal calorifier does indeed have an internal pipe bent towards the wall of the cylinder but it is labelled "Cold in". The "hot out" connection is around 30mm separated from the wall. "Cold in" is required (sensibly) to be at the bottom.

Checking with Surecal, they assure me that the labelling is correct.

Accepting that there is no danger resulting from this (except perhaps with a huge angle of heel and heating supplied by the central immersion heater;- very unlikely due to the non-availability of mains power at times of heel) it would seem at least odd.

Any opinions please?
 
My understanding is the same as yours. The instruction book drawings for mine, by Sigmar Marine, clearly show the discharge pipe sloping upwards inside the calorifier, to a point at which it touches the wall. The text makes it clear that this should be absolutely at the top.
 
I have just fitted a 40lt Surecal horizontal calorifier. Its all plunbed and wired in but untested until the weekend. I will let you know what happens.
 
Sometimes there is a non-return valve between the hot and cold systems, otherwise the pressurised air in the calorifier can push the hot water back into the cold system. In that case, with zero airspace, hot tap might spurt a bit. Or the pressure relief valve might drip into bilge just enough to get really mouldy!
Not saying an air space is right, just suggesting possible reasons for wanting it.
Personally I would want the minimum airspace, to minimise sloshing noise near my bunk for one reason.
I think if you have an immersion, you may get localised boiling on the element, so you will need a bit more expansion capacity?
I don't think losing a litre or so of hot water capacity will matter - at least until I'm the last to shower!
PS when I re-did my system, I found 10mm plastic plumbing was good for the supply to the shower, adequate flow rate, runs warm quicker, and I could run the pipes with no joins.
Hope that Helps.
Cheers,
 
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Sometimes there is a non-return valve between the hot and cold systems, otherwise the pressurised air in the calorifier can push the hot water back into the cold system. In that case, with zero airspace, hot tap might spurt a bit. Or the pressure relief valve might drip into bilge just enough to get really mouldy!

[/ QUOTE ]Wouldn't disagree but a better answer is to have a second accumulator or expansion vessel connected between the NRV and the inlet to the calorifier like this.
 
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Wouldn't disagree but a better answer is to have a second accumulator or expansion vessel connected between the NRV and the inlet to the calorifier like this.

[/ QUOTE ]An even better answer might be to have the expansion tank on the outlet side of the thermostatic mixer.
 
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An even better answer might be to have the expansion tank on the outlet side of the thermostatic mixer.

[/ QUOTE ]Maybe. The reason I didn't do it that way in my installation was that the accumulator then fills with hot water from the top of the cal. This would then cool down (wasting the heat) and, when you turned the hot tap on, you would have to run off the tepid water (wasting the water) before the pump cuts in and you got the hot stuff.

Pretty minor consideration, I'll admit, but I couldn't think of any disadvantage in connecting it to the input side of the cal. (and it worked perfectly).
 
Because if the thermostatic mixer blocks backwards flow into the cold feed, the expansion tank in the position you've recommended wouldn't work. Someone mentioned Surecal calorifiers - they fit thermo mixers as standard and their installation instructions include an expansion tank on the hot outlet pipe.
 
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when you turned the hot tap on, you would have to run off the tepid water (wasting the water) before the pump cuts in and you got the hot stuff.

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As the feed to the heads is a long run, I am fitting a whale in-line pump to recirculate the hot feed back to the tank inlet. In the heads it passes through a SS tube fiddle which when hot serves as an indicator that the hot water has arrived. The recirculation is then switched off and the faucetor shower tap turned on.

That's the theory!
 
Won't your ss tube fiddle get too hot to touch?
Or is it downstream of the thermostatic mixer?
With an eberspacher, the hot water can get very hot, wouldn't want the grab rail in the heads to be nearly that hot!
Probably misunderstanding your plan!
Didn't have the thermo mixer in my system, in a future boat i'd possibly put in a thermostatic shower?
 
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Won't your ss tube fiddle get too hot to touch?
Or is it downstream of the thermostatic mixer?
With an eberspacher, the hot water can get very hot, wouldn't want the grab rail in the heads to be nearly that hot!
Probably misunderstanding your plan!
Didn't have the thermo mixer in my system, in a future boat i'd possibly put in a thermostatic shower?

[/ QUOTE ]

It is downstream of the thermo mixer but it could still get too hot.
I think if I put the rail in the return line, once the recirculator stops, it will cool down again. Thanks for the thought!
 
pvb, I think you've misunderstood my setup. It doesn't require any backwards flow through the thermostatic blender to work. Any expansion in the cal leads to water flowing back out of the inlet. This flow would normally be blocked by the NRV but in this setup is 'absorbed' by the extra expansion vessel - and returned into the cal when a hot tap is turned on.
 
[ QUOTE ]
As the feed to the heads is a long run, I am fitting a whale in-line pump to recirculate the hot feed back to the tank inlet. In the heads it passes through a SS tube fiddle which when hot serves as an indicator that the hot water has arrived. The recirculation is then switched off and the faucetor shower tap turned on.

That's the theory!

[/ QUOTE ]Sounds like a really good way of saving the water already in the pipe.
Another good way of saving water is to have a really noisy pump. That way you know when others are hogging the shower!
 
[ QUOTE ]
Another good way of saving water is to have a really noisy pump. That way you know when others are hogging the shower!

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Many years ago, Sue and I took a party of sea cadets, boys and girls, for a weeks charter out of Ipswich. Because of the mixed sexes, the girls ended up on our boat (one of three).
We slowly became aware of the pump running for too long. Investigating, we found that one of the girls with long hair, had just emptied the whole tank washing her hair.

Fair dos;- thereafter, she used a bucket of seawater!
 
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