Solar PV, Immersun and a possible Combi-Boiler

[MicraShed]

Having long thought of Combi boilers as the work of the Devil, Im finally coming around to the thought that they might not be quite so bad.
I still have my elderly Baxi Solo at home feeding a gravity hot water set up and primatic tank but in my static caravan I have a Morco Combi that produces oodles of piping hot water and takes up little space.

Im wondering, if I re-site a boiler into my airing cupboard ( will have to have a roof venting flue) are there any DHW tanks that would work with the combi boiler and with the Immersun - my way of thinking is that if the water in the tank was the correct temp for the taps ( say 55 degrees) then it would go to the taps, but if it was cooler than that then it would be fed to the boiler mixing with mains cold water to bring the temp down a bit but bolster up the pressure? Oh and I forgot to mention the DHW tank would be sited in the loft above the boiler, but itself not have a CWT feed, so I would be looking at some sort of mains fed tank...

Or am I dreaming these things up and should stick to reading Flash Gordon comic books?

My present set up, despite being 21 years old works brilliantly and the Immersun gives us stacks of hot water in the summer months, and the Baxi is working well ( touch wood) The only reason Im thinking about it is the kitchen where the boiler lives is tiny and Im thinking if I can move a boiler upstairs I can get another big cupboard in the kitchen....

 

[Leesparkykent]

Why not move original boiler or install new conventional/system boiler to airing cupboard? What's the reason for wanting a combi? Personally if it was me id upgrade to fully pumped with something like a Worcester Ri boiler and an unvented cylinder..... It will pee all over a combi.

 

[CBR600]

You might find this interesting;

Simple Solar Water Heating with Combi Boiler or Cylinder

 

[Leesparkykent]

You might find this interesting;

Simple Solar Water Heating with Combi Boiler or Cylinder

Don't think the op has solar thermal as an immersun is mentioned. An immersun uses the excess to heat the hot water.

 

[CBR600]

Lee

Have a read of the link and you will see that it works with either PV or thermal. It is also specifically compatible with an Immersun (although it will work with most load controllers I understand).

 

[Leesparkykent]

Lee

Have a read of the link and you will see that it works with either PV or thermal. It is also specifically compatible with an Immersun (although it will work with most load controllers I understand).

My bad....didn't read that far down.

 

[Worcester]

There are a number of ways to use a cylinder with a combi.

The problem with combis is the maximum flow they can give, OK for one bathroom and kitchen, you'll struggle when you get more bathrooms.

Pop over here: there's loads of help : Central Heating Forum

Check out also this: Plumbing in solar thermal to a combi boiler (combination boiler / geyser) | Solartwin ? From Genfit (ignore the solar thermal element and substiute immersion and immersun)

Some combis can accepted preheated water , some not.

Also http://www.alpha-innovation.co.uk/products/Solarsmart/SolarSmart


In general combis are only suitable for smaller properties.

 

[MicraShed]

Why not move original boiler or install new conventional/system boiler to airing cupboard? What's the reason for wanting a combi? Personally if it was me id upgrade to fully pumped with something like a Worcester Ri boiler and an unvented cylinder..... It will pee all over a combi.

The original boiler is wall vented - the airing cupboard is on a party wall and as much as my neighbours get on my chuff, finishing them off with CO fumes isnt something I want to be responsible for - so a powered flue venting through the roof with the DHW tank above this (in the loft) would be ideal.

There isnt the space on an external wall to place the old boiler now as where I would have put this in the loft is taken up with the inverter and PV array gear. The loft isnt that big.

I'll have a look at that document - thank you.

 

[Martyfox]

Although it'd be adding more new kit, Sunamp PV and their knowledge of feeding pre-heated water to a combi via proportional controllers, may be able to provide a neat solution for you. No personal install/operation experience, but it's interesting.

SunampPV | Sunamp

 

[LeeH]

I've just had a unvented system fitted, would never go back to a combi.

It made the PV more straight forward too.

 

[solarsavings]

Integas combi, Rapid, Hre or Eco will take pre-heated water. Couple that with a small 90-100ltr unvented.