new boiler + unvented cylinder - mains flow rate at 14 l/m

[Snoop]

Dear all - first post, having spent sometime reading the various posts related to flow rates, unvented cylinders and new boilers, I think I need some advice:

- 1 bathroom + 1 shower, possibly another one to be added
- water flow rates on 1st floor are very poor; upstairs bath / shower is poor
- currently a vented system with a cold water tank in the loft, no real height hence poor flow
- 4-5 adults in the house during mornings and evenings, kids have grown up!
- hence the unvented cylinder + new boiler seems best option

Thames water measured pressure and flow rates, 2.5 bar and 14 l / min.

Questions:-

1. what would happen with such a low flow rate? Most cylinders states 20 l/m. Would the energy efficiency be impacted or just get a lower flow rate to the taps?

2. is it worth buying the boiler / cylinder from the same manufacturer - I like the sound of the Vailiant ecoplus 637 + IStor cylinder

3. any issues with putting both into the airing cupboard - replacing existing cylinder and Potterton nettaheat boiler.

4. I have TW coming to provide cost of upgrading mains pipe to a higher bore, but they do so only to the property boundary. Any views on expected costs?

5. should we just replace boiler + cylinder, then if required upgrade the water supply, as suggested by one of the plumbers quoting?

Thanks
Snoop

 

[Reg Man]

Is it possible to upgrade your incoming mains water to a larger diameter pipe? You should then size it to achieve more than 20 litres per minute. Your pressure sound fine.

 

[Snoop]

Thank you, Reg Man. Thames Water are coming to give me a cost to upgrade the incoming water main.

I do wonder whether we go for the boiler + cylinder, regardless?

 

[SimonJohns]

Boiler and cylinder IMO

Far better system

Also fit 2 immersions for when boiler packs up (cant do that on a combi)

 

[lame plumber]

if the pipework is on your lnd, cheaper to use your own plumber/ground workers to link back to stop valve/meter.

 

[Ermintrude]

Don't water co do free change of meter if lead service??