Extension about to get underway - new CH system advice.

[enrm6]

Hi and thanks in advance.

I've read a fair bit here but I'm not sure I've gleaned enough to know what to do, so here goes:

We currently have a 3 bedroom detached house with an extended downstairs which is quite large. We currently have a total of 11 rads fed by a Worcester Bosch Highflow 400.

At present the boiler is fine (we've not owned this house long) but whilst it is a bit of a beast, size wise, it provides loads of extemely hot (even when turned down) water, pretty much instantly which is much nicer than the Ravenheat in our last house. My understanding is that this boiler keeps a supply of water constantly heated so it is available when required hence the instant hot water.

We currently have one bathroom and the boiler seems good enough for one shower though the flow does drop if we run a tap at the same time as the shower being on.

Now here's where I need some advice. We are having an extension to increase upstairs to match downstairs and will end up with 5 bedrooms and two bathrooms.

We will in this process be updating the central heating and in advance of what a plumber or three is going to recommend me I wanted to understand a bit more what my options are likely to be so that I at least go into the conversations with my eyes open.

I guess I could go like for like and get another WB Highflow 440 but I wonder whether these are a bit overkill, but then my shower and tap experience suggests otherwise. I also wonder about whether my mains pressure is up to a massive boiler but I guess a good plumber will be able to give me some truths about that. Maybe a CDi 37 is more appropriate? The alternative is a System boiler setup which seems interesting but I've never had one and cant help but think keeping water hot all the time seems like a waste but perhaps its all more clever than that. It would at least on paper seem to be the thing if we want to have two showers running at the same time which is certainly possible.

I've also read about weather compensation which sounds like a great idea but then the forums also give the idea that its not for everyone.

Anyway, enough waffle from me, any help massively appreciated.

 

[Agile]

Unless you upgrade your mains water there are no easy solutions.

But I question why you are making all these bedrooms?

The obvious question is how many people are to live there ?

If you are opening a B&B then you will have to invest in a proper water supply strategy.

If its only two people living in such a large house then what you have will continue to cope.

Your boiler can also heat an unvented cylinder but that still needs adequate mains flow rate.

Tony

 

[Hugh Jaleak]

Just my thoughts, but it may be an option (space permitting) to have a cylinder fitted with a cold storage tank to feed one bathroom. Existing boiler can be used to heat the cylinder on a Y or S plan arrangement, and continue to serve second bathroom as current setup. (With a twin coil cylinder, solar energy is also an option to help heat the water). Should 2 showers be required simultaneously then boiler can feed one, tanks the other, especially if the mains supply isnt man enough.

Modern cylinders are supplied with a factory fitted foam jacket, heat loss is minimal, so the boiler will effectively only have to heat the water to replenish that used.

 

[looneyfitter]

I would bin the CWST idea as you will still have poor pressure. If upgrading your cold main isnt an option then you can also look into accumulators. As mystery said. The viessmann 222 and 242 are awesome....

Worcester is completely overpriced and living in the past if you ask me.

 

[Agile]

The latest Worcester HiFlows are nice bits of equipment and the W/C is better than the Vitotronic 200 in my opinion.

Thats because it allows you to set the proportion of inside/outside temp that it works on.

Tony

 

[enrm6]

Thanks for the info.

So if I understand correctly the suggestions are mostly some form of variant of what we have already: combi with built in water storage (storage combi?), WB or Viessmann. The viessmann seems somewhat more expensive though.

All with the caveat of the mains water flow.

 

[looneyfitter]

Thanks for the info.

So if I understand correctly the suggestions are mostly some form of variant of what we have already: combi with built in water storage (storage combi?), WB or Viessmann. The viessmann seems somewhat more expensive though.

All with the caveat of the mains water flow.

You get what you pay for matey the 242 is solar ready too and very cleaver.