New boiler and heating system

[boatboy]

Hi, new to this forum.

I'm looking to upgrade my boiler (potterton profile, 25yrs old but running fine - touch wood).

House is 3 bed semi, 1 bathroom, wetroom with electric shower and possibly looking to do loft conversion in Thames water area.
Indirect conventional boiler heating system, 2 tanks in loft and copper hot water cylinder etc

Have checked incoming supply (lead pipe), pressure seems about 2.5bar+ but flowrate is only 9l/min (measured at kitchen tap with bucket and stopwatch).

I've had a few quotes and most were leaning to a combi, which I could see the benefit of - space, gas bill etc. However, with a poor flow rate any shower or bath will be painfully disappointing - currently got a power shower which is great 17l/min.

Have looked into unvented cylinder and system boiler, and like the compromise - good showering and free loft space. Only concern is still with mains incoming flow rate. All the blurb on tanks and boilers generally only talks about pressure and not flow rate.

Can anyone give me some advise on this

Rough cost of upgrading incoming lead main, incl TWUL input, is £3-4k and a lengthy process so not a goer really.

Thanks in advance

 

[kevplumb]

to be honest neither is a combi or unvented unless you can do something about the incoming supply

 

[doitall]

Power shower would have to go, if you have a combi for starters.

Do you have a basement or outbuilding you could use as a plant room for an storage tank and pump set, plus unvented cylinder.

 

[kevplumb]

could always fit an accumulator

 

[doitall]

could always fit an accumulator

True, and a 6ft x 3ft tin can standing in the lounge would be quite a talking point.

 

[boatboy]

No, not really any space other than existing airing cupboard and loft.

An accumulator I presume is some sort of holding tank

Is 9l/min too low for a 180l/210l unvented tank, and presumably 9l/min in from the mains is what I would get out of the unvented tank in terms of showering performance.

 

[doitall]

Too low for anything by x 3.

 

[kevplumb]

No, not really any space other than existing airing cupboard and loft.

twas a joke

 

[boatboy]

what are my options ?

Upgrade existing conventional boiler?

 

[doitall]

A storage tank and a pump, or what you have now.

Yes you can upgrade the old boiler to a heat only condensing boiler.

 

[D_Hailsham]

I'm looking to upgrade my boiler (potterton profile, 25yrs old but running fine - touch wood).

If the boiler is working properly, the only valid reason for up grading is if it is unable to meet your heating and hot water requirements.

Which Profile is it?

possibly looking to do loft conversion in Thames water area.

You need to make up your mind about this before deciding what to do about the boiler.

It would mean either relocating the two tanks (say into the apex of the roof or an unusable part of the loft), or replacing by a combi, or a sealed system with a mains fed cylinder for hot water.

 

[bengasman]

At more than 2.5 bar, it is likely that the 9 l/min is caused by a restriction somewhere. Could be small bore kitchentap or stopcock not fully open, or even a problem with the streetvalve.
Worth investigating before spending thousands on a new heating system.

 

[doitall]

It's an old lead mains Ben, probably has a 3/8 bore, and the 2.5bar is a guestimate.

 

[bengasman]

Guess I missed the bit about the guestimate.
Nothing better than a custard giving you accurate info.