boilers, tank, expansion tank, Sunamp alternative, radiator alternative... erm... bit of everything

[Del-inquent]

I wasn't really sure where to post this, as I'm trying to build an overall picture of options and pretty much everything needs looking at, if I've posted it in the wrong place please do correct me, still quite new here.

Overview:

We're trying to purchase a small 3 bed chalet bungalow. I'm trying to get my head around what could / couldn't be done with it. At the moment it's badly laid out, has next to no storage spaces and at some point had a central heating system installed that I think was designed by a 2 yr old with crayons. Very recently a new Worcester boiler has been fitted, though.

There is one real cupboard downstairs. It has the water tank plus a pump in it, that's that cupboard full. It's also in a really bad position and ideally the cupboard would come out completely and be moved. 

There is one usable "cupboard" upstairs in the eaves to one side of the dormer. That has the cold water tank / overflow tank in it...

To make the place "useable" we would like to extend the dormer to enlarge the 3rd bed and install an en-suite to the main bedroom but that would leave no space at all to have a cold water tank / overflow tank. 

I'm looking at the sunamp thermino as that would fit in a space in the kitchen and remove the need for the cold water tank, plus allow for solar top up. What could I do about the overflow tank for the heating, though? What's the most compact solution for replacing that? The alternative to this would be replace the almost-brand-new boiler with a combi, but I've lived in three places with combi boilers and hated it every time - wife washing up, 14 yr old running hot taps full blast for no apparent reason meanwhile I'm stood turning blue in the shower and the heating has turned off for half hour because the boiler couldn't cope. 

When it comes to the heating system itself, the specification appears to have been "please place the largest possible radiators in the most inconvenient / useless location, preferably offset to ensure they line up with nothing at all". Half under a window, just off centre in the middle of the only usable wall, behind a door so you can't open it properly...

So as they're all going to have to come out and be re-sited I was wondering about the alternatives, thinking maybe thermal skirting, but not finding a lot of positive feeback stories on those so far.

[JohnMo]

Over flow tank for central heating is the easy bit make it pressurised.

 

Radiators need to be sized to suit the room requirements, skirting heating pretty small output, but it depends on your heat losses.  You would need to do a heat loss calc, to establish what you need kW wise and then look at the options.

 

A combi can be a good option, but you have to plumb it differently from normal. You need a small preheat cylinder, the below shows a 25 and 50l cylinder that sits below the boiler.

Some reading info

 

Combi-SuperFlow-White-Paper-v1-2-4.pdfCanetis-SuperFlow-Product-Sheet-WE-050318.pdf

I have a similar system and water production is great.

 

Certainly you get the cylinder and a combi that takes pre heat water for less than sunamp. And it will take up less room.

[Del-inquent]

3 hours ago, JohnMo said:

Over flow tank for central heating is the easy bit make it pressurised

leaves me with a tank still though, looking for methods that don’t involve a tank but potentially retain boiler as-is if possible.

 

interesting in the preheated though I’ll look at that, cheers  

[Nickfromwales]

11 hours ago, Del-inquent said:

looking for methods that don’t involve a tank

Do you have room for a horizontal unvented cylinder in an eave space?

 

[Del-inquent]

14 hours ago, Nickfromwales said:

Do you have room for a horizontal unvented cylinder in an eave space?

 

 

Could probably just about fit a coke bottle on its side in the eaves at the front, that's about it 😂

(hence wanting to get rid of the tank from its current space, storage is seriously non-existent and the planned works to extend the dormer will mean even less as the only bit of eave that is bigger than a mouse hole will be gone)

 

[Nickfromwales]

From a cost / simplicity PoV, you could easily and quickly install a high-flow heatstore combi such as a Vaillant 938. Deeper than a regular combi but DHW output is very good as it has 2x 7.5L tanks which store hot water at high temp to blend into the outgoing, instantaneously produced, DHW flow. As you say, no good for solar but with space at such a low premium maybe electrical batteries vs a heat battery would be a better investment. There's only so much DHW you can use all summer at the end of the day!

The SA would fit under a worktop if you get the model 3rd biggest in the range, but they're just eye-wateringly expensive these days. 

Do you have PV atm?

[Del-inquent]

On 17/01/2023 at 07:03, Nickfromwales said:

From a cost / simplicity PoV, you could easily and quickly install a high-flow heatstore combi such as a Vaillant 938. Deeper than a regular combi but DHW output is very good as it has 2x 7.5L tanks which store hot water at high temp to blend into the outgoing, instantaneously produced, DHW flow. As you say, no good for solar but with space at such a low premium maybe electrical batteries vs a heat battery would be a better investment. There's only so much DHW you can use all summer at the end of the day!

The SA would fit under a worktop if you get the model 3rd biggest in the range, but they're just eye-wateringly expensive these days. 

Do you have PV atm?

No PV at the moment but I have been given notice that some might be available in the very near future at a very, very attractive price. I'll have a look at the Vaillant 938, cheers. The SA is "rather pricey" as you say but if it does the job well, I'm not adverse to getting one. As long as I can sort the heating out in such a way that I don't have to have the overflow tank any more!