what boiler system if low mains water pressure

[MikeJEN]

Hi, with a loft conversion due in the near future I'm starting to research various boiler systems. At the mo we have a conventional boiler on the ground floor, hot water cylinder on the first floor and could water tank in the loft. House currently has 1 bathroom with shower powered with a water pump. The loft conversion will add an ensuite shower room and obviously the cold water tank will have to go.

I'd like a boiler system to enable both bathrooms to be used at the same time with no loss of hot water. My research suggests an unvented cylinder would probably be best...but only if there is suitable mains water pressure. What are the options if mains water pressure is low?? Have an electric shower in the loft ensuite and combi to power everything else? I ideally don't want an electric shower. Any advice greatly appreciated.

Thanks
Mike

 

[PullerGas]

I think you're trying to walk before trying to crawl Mike. First establish your dynamic incoming mains water pressure & flow rate. You may need an incoming mains upgrade, but that'll save you money in the long run.

 

[MikeJEN]

Yes Pullergas, should probably get the pressure and flow rate established first then decide but was just wondering the options if flow rate was low. May never come to need to it but was just curious.

What is the approx cost of upgrading incoming mains feed? We have a water meter on the footpath out the front of our house approx 10-15 feet from the front door.

Thanks

 

[PullerGas]

Yes Pullergas, should probably get the pressure and flow rate established first then decide but was just wondering the options if flow rate was low. May never come to need to it but was just curious.

What is the approx cost of upgrading incoming mains feed? We have a water meter on the footpath out the front of our house approx 10-15 feet from the front door.

Thanks

If your water meter is that close Mike I think it would be very favourable to get it upgraded regardless. Check the incoming main performance first though eh.

Unvented, as you say, is the way to go & with a brand new incoming supply there's limited chances of an issue.

 

[MikeJEN]

Cool, thanks.

 

[dilalio]

If the CWS is going, which a loft box usually dictates, then unvented or a good combi is the route you'll need to take.
As PG said - check the flow. At kitchen sink then open another cold outlet and check again. If poor, could be a stopcock change, then rerun incoming main change which is always recommended anyway due to old underground pipework. But, bear in mind that local water providers seem to be diminishing the minimum flow and pressure they have to supply you with lately (in North London anyway) and if it's poor at the meter you'll need to be considering an accumulator and break tank - we've had to install these on occasion.

 

[MikeJEN]

Ok, a few things to consider but will get the water pressure flow rate checked first and take it from there. I'm based in north London so let's hope it's not too bad! Any idea of cost to get decent water pressure sorted if it needs it? The cold water tap on the down stairs toilet, which is right next to the boiler (not sure if relevant or not), literally has the water shooting out and sprays everywhere when it hits the sink so hopefully that's s good sign.

Thanks for the info guys.

 

[dilalio]

A few of us on here are in north London. PM if you wish.

 

[MikeJEN]

Ok, just more thinking out loud on this...

Is having one unvented cylinder and new boiler to supply hot water and heating for the whole house more cost effective than having a new combi to supply loft hot water and heating to loft conversion and another combi to supply hot water and heating to rest of house. Loft conversion pipes, etc would be totally separate from pipes in rest of house.

 

[dilalio]

It's more than just about cost effectiveness! Luxury, comfort and redundancy come at a price!

 

[bernardgreen]

We have a water meter on the footpath out the front of our house approx 10-15 feet from the front door.

Equally important is the length and diameter of the service pipe from the mains in the street to the water meter. The water company will be reluctant to improve that pipe if your supply already meets the minimum flow and pressure requirements of the supply contract.

 

[Agile]

You should aim for a minimum of 22 litres per minute whilst leaving 1.0 bar pressure in the pipe work.

Someone I know usually charges about £500 for a new 32 mm supply if close to street.

Then a new or existing boiler heating an unvented sized at 50 li plus 50 li per person.

Tony

 

[MikeJEN]

£500 sounds ok...I was expecting a lot more. Water meter is about 4.5m from the front door so not far. Drive nothing special so a poured concrete finish would be fine. My water supplier (affinity water) have said that if I upgrade to 32mm from meter to my house they will do from meter to mains for free if lead pipes still in place. Seems a no brainer really.

In terms of set up I assume unvented cylinder and one boiler is better than two separate combi's?

Yep, been doing a bit of googling on cylinder size and will go for 200li minimum if unvented cylinder is the best option.

Thanks for everyone's input.

 

[Agile]

That price is normally when the front can be easily dug so the pipe can be moled. Probably more if concrete has to be broken through.

Thats also if he can access meter connection by digging from property side so supplier is not involved.

Could be up to £1500 or more if supplier and concrete involved.

Tony

 

[MikeJEN]

The meter is right outside the drive in the pavement so assume easily accessible. Can't be more than a couple of days work can it to dig up concrete lay a pipe and pour new concrete in??