Calorifier

NickB

Anyone else installed a Calorifier for hot water in their self build?
I specified pre disposition pipework (the pipework for rear heaters in minibuses) when I placed the order for my new Ducato.
I chose an insulated stainless steel Nautic model15ltr that gives 15ltr at 85°C but through the blender 26ltr at 43°C with a built in back up 500w immersion heat built in.
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wildebus

Forum Member
looks good. good use of engine energy when driving.
So you could specify the plumbing but not have an actual heater as part of the FIAT build? That is handy (I presume they just looped the pipes?)
If I kept my T5 I was tempted to swap out the rear HVAC unit for a calorirfier but changed vehicles again.

Be interesting how you get on with it and if anything you would alter after using it for a few months (I'm mentally planning my next build for the winter and this kind of hot water system would be of interest to add in, teeing off the coolant pipes :) )
 

NickB

Yes you are correct the 2nd picture shows the loop back. There is a Fiat switch on the dash which operates an electrovalve which allows the hot coolant from the engine to flow onto the habitation area.
I've been using it for a couple of months usually switch it on for 30mins before stopping.. lovely tank full of piping hot water. As it's insulated the water temperature only drops a few degrees overnight. The blender valve compensates for this temperature drop by using less cold water.
The Fiat dealership said that they had never been asked for the pre disposition of pipework ever.
I worked it out a few years ago when I discovered that 'every?' Canal boat /cruiser has one fitted... an engine is an engine is an engine... unlike garages if you go to a chandler it's off the shelf technology.... even listed in the Force4 catalogues Etc.
 

wildebus

Forum Member
Cheers. I didn't notice the detail in the 2nd pic and your clear description of fiat providing it! doh! Neat to have a electrovalve there as a master control.

My own solution in my current is a purely electric one (a 10L insulated on-demand water heater) as I didn't consider retro-fitting coolant pipes, but I take a similar approach to you in usage terms... switch it on when I start out on a trip but rather than using the engine to transfer heat to the tank, it uses alternator power to help feed the inverter via the split-charge kit. I find if I leave the heater enabled, it kicks on for a few minutes every few hours to maintain the temp.

Your solution I prefer though (y)
 

NickB

Thank you... so far so good I'm happy with it.
BTW I did put two boiler fix valves in as well in case I want to take the calorifier out without having to drain all the coolant from the engine.
 

wildebus

Forum Member
NickB said:
Thank you... so far so good I'm happy with it.
BTW I did put two boiler fix valves in as well in case I want to take the calorifier out without having to drain all the coolant from the engine.
Click to expand...
Just to the left of the wooden frame? Can just make them out :)
Always good to have isolation :) (I installed a DHW system in my last house fed by Solar System, Combi Boiler, Immersion Heater and Rayburn Range, and could isolate and bypass any part of it either manually or automatically via various shut-valves and TMVs. Worked very well and great to be able to utilize 'free' energy :cool: )
 

NickB

That's the best way. I did "think" about a heat exchanger for the van on the roof for a few nano seconds. You have a great design there.
In my house which has the slopping roof sides, I fully insulated with 6" kingspan. Creating what's called a warm roof of the attic. I had the combi located up there along with a 50m coil of 25mm dupont pipe on the inlet to harvest the ambient heat to pre warm the water going into the boiler.... the plumber came back the following day (at his own cost) because he didn't believe it would work armed with a digital thermometer. . It had a 4°C gain.... it's been up there for over 4 years... probably paying for itself now.
 

wildebus

Forum Member
NickB said:
That's the best way. I did "think" about a heat exchanger for the van on the roof for a few nano seconds. You have a great design there.
In my house which has the slopping roof sides, I fully insulated with 6" kingspan. Creating what's called a warm roof of the attic. I had the combi located up there along with a 50m coil of 25mm dupont pipe on the inlet to harvest the ambient heat to pre warm the water going into the boiler.... the plumber came back the following day (at his own cost) because he didn't believe it would work armed with a digital thermometer. . It had a 4°C gain.... it's been up there for over 4 years... probably paying for itself now.
Click to expand...
Getting a bit off-topic from your Calorifier, but on the home DHW bit, it took me a few calls to find a heating guy willing to commission the boiler even though all he had to do apart from connect the gas was to connect to the tails that I had already in place as they just didn't understand the idea of a Combi with pre-warmed water (like you have) for one thing. In the summer, the boiler never came on; in the winter I was feeding it with water upto 20C warmer than the mains supply so had summertime-sized HW bills in January (I did have to source a continental boiler as no UK ones supported a pre-heated water inlet at the time).
I was well chuffed with how well it all worked actually as the idea of having a Combi (benefit - no hot water storage) and Solar (benefit - hot water store from sun) don't traditionally go together :)
 

NickB

Yes good you noticed that about the suitablity of your boiler to accept preheated water... I double double checked with Worcester the maximum allowable inlet water temperature. . I can't remember what that is, its in the paper work with my boiler in the attic.
19- 20°C is the average air temperature (so that's the pre heated water temperature as well) now since the insulation installed. The rafter insulation (I put it in) Kingspan designed it. It keeps the attic temperature almost constant winter and summer.
Now the Combi only has to raise the water around 20°C to get to 40°C.
 

wildebus

Forum Member
One of the 'issues' with the pre-heated water with most boilers was they wouldn't operate at part-power (can't recall the proper term) so wouldn't get the best benefit from feeding warmed water. Bought a dutch boiler (they are much more advanced with this kind of stuff) specifically for this.
I had the advantage (if it can be put that way) of inheritating a very poor setup when it came to both CH and DHW so was able to start from Scratch!
The Hot Water was only only supplied by an immersion or the Rayburn; the Gas Boiler only did the heating (weird or what!); the Rayburn was a combo stove and hot-water range but the hot water went to a big radiator acting as a heat dump as well as the hot water and was very inefficient as a water heater - so it was cheaper to run on the immersion!
The only thing which would change in the setup was I bought a thermal store (kind of the opposite way of working to a hot water cylinder) which had an integrated water expansion tank on top. The Thermal Store was great generally but that expansion tank meant the top of the tank wasn't insulated (just a copper skin between the expansion and the store top) and the heat could go to the expansion and then dissipate so not as efficient as it could be (I ended up draining down as much as would be allowed and put some polysytrene insulation on the bottom to try and help it, but a separate tank to the store would have been a lot better.

Anyways, back to calorifier .... top job :) might ask you some more questions on this in a few months :p
 

NickB

Anytime. .. thanks again. .
BTW was modulating the word you were looking for?
 
SquirrellCook

SquirrellCook

Forum Member
NickB said:
Anyone else installed a Calorifier for hot water in their self build?
Click to expand...

We've been using one in "Murky" for about 14 years now. Replacing the electric element for a 500w one was a very useful upgrade. Allowing it to be heated from a small generator, or as Dave pointed out using surplus solar electric energy to heat it.
We also have a 12kw eberspacher that can preheat the engine and or heat the calorifier and other heaters.
One problem we found that you might encounter is heating the cold water. It doesn't happen very often, but annoying when it does.
On the new build "Betty" we are going to try and isolate any cold parts away from the calorifier. Water pump, expansion tank and plumbing.
As you mention it's really good how long they hold their heat. We try to get ours as hot as we can to maximise the benefit.
Ours is normally kept in the heating circuit whilst driving, so we always have hot water.
The main thing that upsets me is no one told me about them sooner.
I'm so impressed I purchased another one for the kitchen at work.

Mark
 

ScoTTyBEEE

Forum Member
Is there any specific reason for the electrovalve switch? Since the whole unit is insulated I wouldn't see a problem with it being permanently connected, it's only excess heat in the summer I could envisage as a problem.
 

NickB

Not that I can see other than maybe a slight energy save. As the volume of coolant water would be less most of the time.
 
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