Reliable calorifier suppliers?

[Tony Brooks]

6 hours ago, TheBiscuits said:

 

I'm not sure that's correct Tony.  I think the mixer valve always allows some hot water out but adds cold water above the set temperature, so there should always be a way for the pressure to equalise either side of the valve.

 

Certainly Surecal installation instructions tell you to put the expansion vessel after the valve:

 

An expansion bottle should be fitted on the hot supply between the thermostatic mixer and first take off (i.e. Taps) This will relieve the increased pressure caused by hot water expansion.

 

 

 

I  was not sure if any thermostatic valve could totally close off the hot supply so put that stipulation in, just in case. As Surecal seem to ft their own mixing vale at the factory as standard, they can ensure their valve can't close the hot supply off. If the valve always leaves a bypass for the hot water, then it should make no difference to where you locate the expansion vessel.

[Ex Brummie]

19 hours ago, Tonka said:

Are you quoting a fact this time or is it just a hunch

This is fact. Just make sure that there are no non return valves between the vessel and the cylinder.

Eta: That will teach me to read all the post before responding.

Edited October 6, 2021 by Ex Brummie

[MtB]

10 hours ago, TheBiscuits said:

An expansion bottle should be fitted on the hot supply between the thermostatic mixer and first take off (i.e. Taps) This will relieve the increased pressure caused by hot water expansion.

 

Like Tony, I see no reason for the expansion vessel to be fitted before the first take off. A vessel will work if fitted anywhere along the hot water outlet run. 

 

There could be a non-technical reason for that instruction which isn't clear though. Perhaps without that instruction, their technical help line gets more calls questioning expansion vessel location, for example. 

[TheBiscuits]

1 minute ago, MtB said:

 

Like Tony, I see no reason for the expansion vessel to be fitted before the first take off. A vessel will work if fitted anywhere along the hot water outlet run. 

 

There could be a non-technical reason for that instruction which isn't clear though. Perhaps without that instruction, their technical help line gets more calls questioning expansion vessel location, for example. 

 

Dunno, I didn't write their installation instructions.  I fully agree that the pressure will be the same regardless of the location.

 

The only logical reason I can think of for that instruction is that you'll get the cooler water from the expansion vessel out of the tap first followed by a continuous stream of hot water direct from the calorifier. 

 

If the expansion vessel is located further down the pipe you might get a pulse of cold water, probably just as you step in the shower ...

 

I'm only guessing here though - my expansion vessel is located where they recommend, simply because it's the best place for it on my boat.

 

 

[IanD]

Does anyone know of any calorifiers which can have extra-large heating coils fitted to absorb more/all of the heat from a Webasto/Eberspacher?

 

From the measurements Dave Jesse made a standard Surecal one only absorbs 1.1kW, which is not enough to stop the heater cycling if the radiators are off -- even the newest ones only throttle down to a bit less than 2kW.

 

https://www.perseverancenb.com/post/how-to-measure-the-calorifier

 

This means leaving some external radiator(s) on (e.g. towel rail) even if you only want hot water in summer, also doubles the fuel consumption because you have to run it twice as long, and means a long time to warm the tank up since it only heats up by 16C/hour.

 

The only other solution I can see is to use a twin-coil one with both coils connected to the heater (should absorb 2.2kW which will stop cycling), which then means you don't have one free for the engine/genny...

 

[maybe not so bad for an electric/hybrid boat where genny doesn't run for long hours anyway so isn't much use for hot water]

[David Mack]

How about a bespoke calorifier with 3 (or more) coils?

[IanD]

10 minutes ago, David Mack said:

How about a bespoke calorifier with 3 (or more) coils?

Supplier -- maybe here?

 

https://www.coppercylinder.co.uk/

[peterboat]

On 05/10/2021 at 11:25, MtB said:

 

Yes. 

 

Newark Copper Cylinder Co Ltd are another well-regarded cylinder fabricator and I see from their website they have now noticed the marine calorifier market. Their prices for custom cylinders are (or were) surprisingly competitive.

 

https://newarkcylinders.co.uk/marine-calorifiers.html

 

 

 

 

 

I have bought from them twice both times great service, price and quality

[IanD]

15 minutes ago, peterboat said:

I have bought from them twice both times great service, price and quality

coppercylinder or newarkcylinders?

[peterboat]

3 hours ago, IanD said:

coppercylinder or newarkcylinders?

Newark cylinders as they are just down the road Ian they will make you what you want, the last boat had 3 coils one for engine, one for backboiler and the top one for solar. Very good price and service 

[IanD]

30 minutes ago, peterboat said:

Newark cylinders as they are just down the road Ian they will make you what you want, the last boat had 3 coils one for engine, one for backboiler and the top one for solar. Very good price and service 

 

So did you use those (expensive!) combined electric/thermal solar panels?

 

If so, how do you deal with the fact that the water temperature is typically around 45C, which is really a bit low for hot water -- unless you use directly instead of mixing with cold water for showers etc. which means a much bigger tank is needed?

 

https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/545246/Solar_PVT_FINAL__1_.pdf

 

PV-T technology only makes technical and commercial sense where there is a suitable use for
the low-temperature heat that the system can provide. Most of the focus is therefore on
commercial and industrial installations where there is year-round heat demand and adequate
space for hot water cylinders, thermal stores etc.

 

Good applications for PV-T are considered to be leisure centres, sports facilities, nursing homes
and small industrial sites requiring pre-heated water. Relatively few domestic properties have
large enough hot water cylinders and hot water demand, to make retrofitting PV-T an economic
proposition.

Edited October 6, 2021 by IanD

[peterboat]

18 minutes ago, IanD said:

 

So did you use those (expensive!) combined electric/thermal solar panels?

 

If so, how do you deal with the fact that the water temperature is typically around 45C, which is really a bit low for hot water -- unless you use directly instead of mixing with cold water for showers etc. which means a much bigger tank is needed?

 

https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/545246/Solar_PVT_FINAL__1_.pdf

 

PV-T technology only makes technical and commercial sense where there is a suitable use for
the low-temperature heat that the system can provide. Most of the focus is therefore on
commercial and industrial installations where there is year-round heat demand and adequate
space for hot water cylinders, thermal stores etc.

 

Good applications for PV-T are considered to be leisure centres, sports facilities, nursing homes
and small industrial sites requiring pre-heated water. Relatively few domestic properties have
large enough hot water cylinders and hot water demand, to make retrofitting PV-T an economic
proposition.

I had a water solar panel which was pumped it worked really well in summer, I was lucky in so much that a mate had a solar panel business up the road. Unfortunately in 2007 it was flooded, fortunately for me I picked up a load of written off panels for peanuts so I could play on the cheap. Nowadays as you know my excess solar heats an immersion heater which works great as well 

[MrsM]

On 05/10/2021 at 11:25, MtB said:

 

Yes. 

 

Newark Copper Cylinder Co Ltd are another well-regarded cylinder fabricator and I see from their website they have now noticed the marine calorifier market. Their prices for custom cylinders are (or were) surprisingly competitive.

 

https://newarkcylinders.co.uk/marine-calorifiers.html

 

 

 

 

 

Another vote for these guys - they supplied 4 cylinders for our last 2 houses. Really pleased they are going into marine products.

[IanD]

30 minutes ago, peterboat said:

I had a water solar panel which was pumped it worked really well in summer, I was lucky in so much that a mate had a solar panel business up the road. Unfortunately in 2007 it was flooded, fortunately for me I picked up a load of written off panels for peanuts so I could play on the cheap. Nowadays as you know my excess solar heats an immersion heater which works great as well 

I was thinking the same way. Of course you've got a lot more excess solar with ~5kW of panels on a wideboat... 😉

 

If I can get a twin-coil cauliflower with much bigger/finned coils -- like are used for "solar" ones? -- then it might also be worth plumbing the genny into one coil. With the normal ~1kW coils and expected short generator running times it's not worth it, better to use both coils for the diesel (HVO?) heater.

Edited October 6, 2021 by IanD

[PineappleGuy]

 

On 05/10/2021 at 17:37, wetfoot said:

Besides the Webasto only outputs at 72 degrees so the water in the calorifier won't get ridiculously hot. The engine is not run frequently enough nor for long enough to get the water up to full engine temperature. 

 

Which Webasto have you got that only outputs at 72 degrees?

Edited October 6, 2021 by PineappleGuy

[MtB]

22 minutes ago, PineappleGuy said:

 

Which Webasto have you got that only outputs at 72 degrees?

 

Que?

 

72c is more than scalding hot and plenty hot enough for rads and hot water!

 

 

[PineappleGuy]

OK thanks. Can the engine coolant get hotter than that? If you run the engine for a few hours would you get hotter water than a Webasto boiler would ever manage?

[MtB]

4 minutes ago, PineappleGuy said:

OK thanks. Can the engine coolant get hotter than that? If you run the engine for a few hours would you get hotter water than a Webasto boiler would ever manage?

 

Yes, a modern engine might run at up to 85c. But why would you want your cauliflower to be so dangerously hot?

[PineappleGuy]

I don't but at the moment there is no control. Should there be a thermostatic valve in the engine coil circuit to limit the temperature reached in the calorifier?

[Tony Brooks]

4 minutes ago, PineappleGuy said:

I don't but at the moment there is no control. Should there be a thermostatic valve in the engine coil circuit to limit the temperature reached in the calorifier?

 

Normally you can either fit a lower temperature engine thermostat, or fit a  thermostatic mixing valve to the hot outlet pipe from the calorifier so it mixes hot and cold water.  In theory fitting a cooler engine stat would increase wear and fuel consumption, but in practice it's not detectable.

[IanD]

12 hours ago, Tony Brooks said:

 

Normally you can either fit a lower temperature engine thermostat, or fit a  thermostatic mixing valve to the hot outlet pipe from the calorifier so it mixes hot and cold water.  In theory fitting a cooler engine stat would increase wear and fuel consumption, but in practice it's not detectable.

 

Normal practice is to fit a mixing valve on the calorifier output, then the calorifier can run as hot as possible (85C), this stores more heat and gives up to 2x more hot water for showers compared to running the calorifier cooler.