Storage combi or UVC choices for new build

[Chablais]

we used 10mm Hep20 to all basins and sinks, some pipe runs will be 15-19m, as Peter W says, flow rate at 3 bar will be fine, people staying at ours comment how quick the hot comes through. Although I have to say, most people are happy to wash their hands in cold water. We used 15mm to utility sink and all showers, 22 to the bath. Hope that helps

 

[ruggers]

Thanks guys. I'm surprised with the 10mm providing the flow, I didn't think it would be up to the job, it makes life easier dropping smaller pipes down the wall from upstairs & hiding them, then just step it back up before the sink & add a couple of 15mm iso valves. I work it out as being 2/3's of the internal diameter of a 15mm pipe. I don't have very good water pressure in my current property, not sure if this plays a part in delivery time.

 

If i use 10mm, there might not be a need for the HWRC with bronze pump unless theres advantages to one I'm unaware of. @Chablais @dpmiller Do you have secondary hot water circuit or not required?

 

@Beckside Thanks for the detail. The info when searching has been limited and varying on it running 24/7 and some saying it cant be turned off so it's good to hear from someone who has it installed, I know it's been around a long time but it's still quite rare in the UK it seems for the majority. On off features are a definite no, WC vs load comp are my choices. The log burner choice was decided some time ago as we liked the idea of one & we have about 8 years worth of logs, but i know what you mean. 

 

 

[PeterW]

6m doesn’t need a HWRC - if you had 15m runs to basins (again they can be 10mm) then it’s different. 

[JohnMo]

WC vs load compensation.  You can have both.

 

Master thermostat, just decreases flow temperature, but it applies to all rooms not just the room the master thermostat is in.

[Chablais]

Defo not HWRC for us, purposely designed NOT to need it, tbh couldnt see the point of making thehouse super efficient and then running HW around the pipe syetem just so you can have instant HW.

If you are super insulated and more importantly, airtight, then a log burner will almost certainly over heat your house in next to no time. We chose not to have one mainly due to pollution issues, but also because the times we could actually light it and remain comfortable would be extremely limited, even here in the Lake District.

 

[Adsibob]

On 13/06/2022 at 20:34, ruggers said:

The 222F has a 100L built in storage tank

My friends have this in a large house and are very happy with it. I almost went with it but we have a giant bath so to be safe I went with a system boiler and UVC. Happy with my choice of Veissman Vitodens 200-W 35kw system boiler. I went with one wiring centre and manifold per floor and then put a Tado thermostat in each zone. I have 12 zones, one in each room. Expensive, but I’m happy with it.

[ruggers]

Chablais, I share your view on the HWRC, if it can be avoided. The 10mm sounds like a good way to avoid this for my furthest outlet.
 

@Adsibob Do you have UFH on both floors, and using the Tado stats, are these still linked to WC or do they replace it? 12 is a lot.

[Adsibob]

17 minutes ago, ruggers said:

 

@Adsibob Do you have UFH on both floors, and using the Tado stats, are these still linked to WC or do they replace it? 12 is a lot

We have UFH on all three floors. I’ve not lived in the house during winter yet, but I doubt we will ever use the ufh on the top floor. I know a lot of people here said not to bother with central heating for the top floor… I should have listened. Could have saved £300 on tados for that floor and a lot more on the UFH itself.

 No WC, not really necessary or helpful with all the Tado smarts.

[ruggers]

Have you found your top floor doesn't need it and is too warm due to the heat rising? It's a shame your limited to Tado with them being so expensive. The prices seem to range from £100-160 each. Did you choose RF or wired stats, is the wiring centre tado too and does it control actuators or jus tell the pump & zone valve to kick in?

[ruggers]

Can ASHP's modulate down as low as a good condensing boiler or does short cycling affect them more if zones were applied?

Does rising electricity prices affect COP?

[JohnMo]

Think the turndown on an ASHP is 3 - 4 to 1.  If you have a 5 kW heat pump you getting down to 1.5kW.  Think the best boiler can do 17 to 1.  But it starts at 30 plus kW, so can come down to sub 2 kW.

 

That's why it important not to over spec a heat pump.