Calorifier and Gas Heater or Just Calorifier?

[lewisericeric]

Hi guys

 

I'm at a bit of a crossroads with my new build. I always thought I'd go with a calorifier and a gas water heater on my new build, but now not sure. (Mostly as I hate the idea of the gas heater unit on the walls).

 

I'm not having diesel central heating, so will have no other means to heat hot water, and always hated the fact I'd have to have my engine on in summer JUST for hot water when it otherwise wasn't needed as solar would take care of the electrical side of things.

 

I am having a solar dump put on my calorifier by my electrician, although he advises these work better on smaller calorifiers and I am having a 95/100litre calorifier...

 

What's the general consensus around having the gas water heaters as well as calorifier? Do any of you have a preference for one over the other? Be good to hear some thoughts!

 

 

[Tony Brooks]

1 minute ago, lewisericeric said:

Hi guys

 

I'm at a bit of a crossroads with my new build. I always thought I'd go with a calorifier and a gas water heater on my new build, but now not sure. (Mostly as I hate the idea of the gas heater unit on the walls).

 

I'm not having diesel central heating, so will have no other means to heat hot water, and always hated the fact I'd have to have my engine on in summer JUST for hot water when it otherwise wasn't needed as solar would take care of the electrical side of things.

 

I am having a solar dump put on my calorifier by my electrician, although he advises these work better on smaller calorifiers and I am having a 95/100litre calorifier...

 

What's the general consensus around having the gas water heaters as well as calorifier? Do any of you have a preference for one over the other? Be good to hear some thoughts!

 

 

 

Depends on how much money you are happy to spend but first are we to understand that you will have no space heating on the boat. No gas, no diesel so that suggest you might have a sold fuel stove so one with a back boiler can heat a calorifier when the stove is alight.

 

There are gas caravan heaters such as this https://propexheatsource.co.uk/heaters/malaga-water-heater

but I expect it will be expensive. Also look at Truma https://www.truma.com/int/en/products/truma-heater

 

If cost is no barrier you could look at installing an Alde 3xxx as boiler for the hot water but they say no copper pipework so if you go this way the sooner you talk to the builder about the plumbing the better.

[Tony Brooks]

PS you could always plumb a small hot water cylinder in series and after the calorifier so you have a small volume cylinder for the solar dump heating. As the solar dump is electric with a thermostat there is no danger of getting scalding water when the engine and solar dump are working together, unlike a calorifier and instant gas water heater, so no extra valves are required.

[Alan de Enfield]

If you are not having a water heater (of any type) then its going to rely on you running your engine for an hour or two just to get hot water - alternative view - you'll probably be running the engine anyway when cruising, or to charge your batteries anyway (unless you have sufficient solar to keep your batteries up to 100%)

 

Or boil the kettle when you want hot water.

 

Only you know how much tyou need / want hot water.

[Mike Tee]

Just a thought - if you end up iced in somewhere, it's a lot easier to carry 10 litres of diesel down the towpath than a full 13kg gas bottle (smaller bottles are so much more expensive than 13KG). So I know you don't want a Ebbersplutter or whatever, but it is worth having a think and maybe changing your mind before the builder gets too far.

[lewisericeric]

1 minute ago, Tony Brooks said:

PS you could always plumb a small hot water cylinder in series and after the calorifier so you have a small volume cylinder for the solar dump heating. As the solar dump is electric with a thermostat there is no danger of getting scalding water when the engine and solar dump are working together, unlike a calorifier and instant gas water heater, so no extra valves are required.

Hi Tony

 

This is interesting. Sorry, gave half a story. The boat builder just built the shell. Fit out is now a combination of me/friends and then an electrician and, of course, gas will be done by a professional too.

 

I could use two  calorifiers then? A larger and a smaller.... is the 'series' plumbing of them a complicated task? Limited knowledge here so any more info would be really useful.

 

Thanks

Just now, Mike Tee said:

Just a thought - if you end up iced in somewhere, it's a lot easier to carry 10 litres of diesel down the towpath than a full 13kg gas bottle (smaller bottles are so much more expensive than 13KG). So I know you don't want a Ebbersplutter or whatever, but it is worth having a think and maybe changing your mind before the builder gets too far.

Thanks Mike

 

The way I see it, the diesel central heating would cost £5k to install and realistically, I don't think I'd be using it at all in another year or two the way diesel prices are going.... I know the same is happening with gas, but gas heaters are a few hundred quid (Morco). It terrifies me I've had another diesel engine(!) never mind chucking money on plumbing/rads/units for central heating....

 

I'm building this boat as an 'apocolypse' boat!!! It's 70ft, two woodburners (not going down the back boiler route) and no central heating. Valid point re lugging the gas bottles v diesel and I am still considering getting a cheap diesel blow heater for additional heat should I need it/can't be a*sed firing up one of the woodburners, but it's options for hot water that's a bit of a bamboozle at the moment.

[rusty69]

For many years our water was heated successfully only by a paloma gas water heater.  Whenever we went anywhere, I always felt a bit robbed that I was losing out from 'free' heat from the engine cooling, so later added a calorifier. I also added an immersion heater, and even dabbled a bit with solar hot water heating.

 

So, to answer your question, a lot will depend on what kind of boating you do, and whether you prefer to lug heavy gas bottles around more often to deal with the increased demand. If you are a summer only boater that does a lot of cruising, then a gas water heater is less of a requirement. If you plan to be in a marina with an electric hook up, you can always use an immersion heater.

 

One thing is for sure. It's likely easier to fit one at the fit out stage than retrofit one later, as I did.

[Tony Brooks]

1 minute ago, lewisericeric said:

Hi Tony

 

This is interesting. Sorry, gave half a story. The boat builder just built the shell. Fit out is now a combination of me/friends and then an electrician and, of course, gas will be done by a professional too.

 

I could use two  calorifiers then? A larger and a smaller.... is the 'series' plumbing of them a complicated task? Limited knowledge here so any more info would be really useful.

 

Thanks

 

The plumbing is not complicated, it is just a length of pipe from the main calorifier hot outlet to the inlet of the small auxiliary one, but make sure there is no NRV between the two or you will need another PRV and expansion tank. Just be aware this is unusual and might waste a bit more heat. In winter when the solar would be doing nothing you may have to run the taps longer to purge any cool water from the auxiliary calorifier. But as it has no water coil connections and as long as the interlink pipe was well insulated the initial water flow may well be hot enough for most tasks after cooling overnight.

 

Best wait for other comments on this idea.

[Alan de Enfield]

 

As the old saying goes "Tis better to have and not to need, than need and not to have."

[lewisericeric]

1 minute ago, Tony Brooks said:

 

The plumbing is not complicated, it is just a length of pipe from the main calorifier hot outlet to the inlet of the small auxiliary one, but make sure there is no NRV between the two or you will need another PRV and expansion tank. Just be aware this is unusual and might waste a bit more heat. In winter when the solar would be doing nothing you may have to run the taps longer to purge any cool water from the auxiliary calorifier. But as it has no water coil connections and as long as the interlink pipe was well insulated the initial water flow may well be hot enough for most tasks after cooling overnight.

 

Best wait for other comments on this idea.

Thanks tony, interesting idea. So the main, larger calorifier would be linked direct the engine, with the smaller calorifier linked to the large, main calorifier, but with no non-return valve.... 

 

If water can pass between the two units, would the engine also eventually heat up the smaller 'solar' unit too? 

[Tony Brooks]

10 minutes ago, lewisericeric said:

If water can pass between the two units, would the engine also eventually heat up the smaller 'solar' unit too? 

 

If they are vertical calorifiers, stacked vertically and joined by a short length of 28mm+ pipe the water MIGHT thermo-syphon between the two, but I doubt it. There might also be a height problem.

 

At the risk of complicating things you could plumb the coils in the two calorifiers in series with the small one receiving water straight from the engine In fact, if you do this the primary calorifier could be smaller because when the engine is running both calorifiers will reach the same temperature after a bit of time.  If you did this I think coil bleed points on both calorifiers might be vital for getting rid of airlocks.

 

First question - Yes.

 

Edited September 5, 2022 by Tony Brooks

[lewisericeric]

16 minutes ago, Tony Brooks said:

 

If they are vertical calorifiers, stacked vertically and joined by a short length of 28mm+ pipe the water MIGHT thermo-syphon between the two, but I doubt it. There might also be a height problem.

 

At the risk of complicating things you could plumb the coils in the two calorifiers in series with the small one receiving water straight from the engine In fact, if you do this the primary calorifier could be smaller because when the engine is running both calorifiers will reach the same temperature after a bit of time.  If you did this I think coil bleed points on both calorifiers might be vital for getting rid of airlocks.

 

First question - Yes.

 

Interesting, thanks.

 

Just going back to an earlier point about lugging bottles in winter, the idea I think would be that the gas heater would be used mostly in summer - when I DON'T want to have an engine running if I'm not going anywhere.

 

In winter, you'll have engine on more for charging, so you'll always have a vast array of hot water via the calorifier. 

 

Does anyone know how complex the Morco heaters are to plumb in? (I'm not talking about gas connection, but rather where abouts they need to sit on the plumbing line?)

[Tony Brooks]

1 minute ago, lewisericeric said:

Does anyone know how complex the Morco heaters are to plumb in? (I'm not talking about gas connection, but rather where abouts they need to sit on the plumbing line?)

 

Anywhere convenient and between the hot and cold lines BUT -

 

If a calorifier is involved you need to fit a two-way valve so hot water from the calorifier can't pas through the gas boiler. If it did there would be a good chance of getting superheated steam from the taps.

 

The valve can be in the cold feed or the hot supply pipe.

[lewisericeric]

1 minute ago, Tony Brooks said:

 

Anywhere convenient and between the hot and cold lines BUT -

 

If a calorifier is involved you need to fit a two-way valve so hot water from the calorifier can't pas through the gas boiler. If it did there would be a good chance of getting superheated steam from the taps.

 

The valve can be in the cold feed or the hot supply pipe.

Thanks Tony, really useful stuff there.

[David Mack]

1 hour ago, Tony Brooks said:

In winter when the solar would be doing nothing you may have to run the taps longer to purge any cool water from the auxiliary calorifier.

You would have to run an entire  small calorifier of water through before you would get any hot water. So unless the auxiliary calorifier is tiny you would be wasting a heck of a lot of water. And if it is tiny, then you haven't provided a useful amount of hot water to avoid the need to run the engine. Better in my view to put the calorifiers in parallel with an L-port valve to select which you draw water from.

If you want to get sophisticated you could have a powered valve driven by some electronics and temperature sensors on each calorifier to automatically choose which tank to use.

[Tony Brooks]

25 minutes ago, David Mack said:

You would have to run an entire  small calorifier of water through before you would get any hot water. So unless the auxiliary calorifier is tiny you would be wasting a heck of a lot of water. And if it is tiny, then you haven't provided a useful amount of hot water to avoid the need to run the engine. Better in my view to put the calorifiers in parallel with an L-port valve to select which you draw water from.

If you want to get sophisticated you could have a powered valve driven by some electronics and temperature sensors on each calorifier to automatically choose which tank to use.

Not if he piped the coils in series, they would just act as one larger calorifier.

[ditchcrawler]

Quote

If its a vertical coliflower and the immersion heater is in the top then size doesn't make much difference as the water heats from the element upwards. Lots of domestic systems have two immersion heaters, one near the bottom on offpeak electricity and one near the top on day time rate to top up if you use all the hot water produced over night. If its a horozontal one its a different story.

 

[lewisericeric]

Just changing tack slightly, what about a diesel heater - aka something similar to the cheap chinese blow heaters, to heat the water in the calorifier? 

Does anyone currently do this? Is it possible? I had Webasto on my last boat, but oddly, for it to heat the water in the calorifier I still had to have one rad open in the boat in summer otherwise it never seemed to heat the calorifier water up? 

[lewisericeric]

1 hour ago, Tony Brooks said:

Not if he piped the coils in series, they would just act as one larger calorifier.

Tony, may I send you a DM somehow?

[Tony Brooks]

1 minute ago, lewisericeric said:

Tony, may I send you a DM somehow?

Yes, or email me if it is easier. Tony@tb-training.co.uk (address already in the public domain so no need to warn me about spam bots etc.)

[Tony Brooks]

1 hour ago, lewisericeric said:

Just changing tack slightly, what about a diesel heater - aka something similar to the cheap chinese blow heaters, to heat the water in the calorifier? 

Does anyone currently do this? Is it possible? I had Webasto on my last boat, but oddly, for it to heat the water in the calorifier I still had to have one rad open in the boat in summer otherwise it never seemed to heat the calorifier water up? 

 

Yes, but often with a valve to isolate the rads. It all depends upon the way it is piped. My guess is that your coil was in series with the rads so if the rads were turned off no water could circulate. One would normally plumb the calorifier coil in parallel with the rads, just like another rad. If it feeds too much hot water back into the boiler when the calorifier is hot then you may need a restrictor valve, but I never found that with my gas  Alde