Replace gravity system with combi boiler

Yaayuh! · 11 Nov 2013 at 12:05

Some point soon i will be looking to get our boiler/central heating system changed.

We have a 12 year old boiler (which is 90%+ efficient, so not too bad) on a gravity system which is old.
Whilst the boiler is efficient, the system isn't. I think our thermostat on the cylinder is bust, the heating controls are old, we have no TRVs, old pipes, cold loft, and a mess of an airing cupboard.

Taking it all into account, i really miss the combi boiler at our last place so i want to get the system updated with a new combi boiler.

What are the costs involved here, including TRVs and maybe a few new radiators? Any estimates?
I wouldn't do any of this my self as i HATE plumbing but the loft tanks can be emptied and left there, wouldn't ask for them to be removed, just disconnected would be fine.

pitchfork · 11 Nov 2013 at 12:32

How long is a piece of string?

Get some plumbers in to quote.

You're basically asking the equivalent of "how much will a new engine for my red car cost"

MaxP779 · 11 Nov 2013 at 12:34

I got something similar done in my 2 bed semi for ~£3k. Comes to £2.3k after the green deal cashback is factored in (not the loan, that's the bad part of the green deal).

Most quotes i had were ~£2.8k, thats for a combi boiler, filter, new shower, TRV's, new thermostat, re-jigging the pipework so it works, power flush, upgrading gas line to 22mm as well. They removed the hot water cylinder and a bunch of copper pipes (all of which i kept) and disconnected the cold tank.

I kept the same radiators though and i dont know if you need a power flush (i did based on the amount of black stuff that came out :eek:

). It could probably be cheaper than what i got as i specced most of the parts myself and they were more towards the high end side.

Yaayuh! · 11 Nov 2013 at 12:48

MaxP779 said:
I got something similar done in my 2 bed semi for ~£3k. Comes to £2.3k after the green deal cashback is factored in (not the loan, that's the bad part of the green deal).

Most quotes i had were ~£2.8k, thats for a combi boiler, filter, new shower, TRV's, new thermostat, re-jigging the pipework so it works, power flush, upgrading gas line to 22mm as well. They removed the hot water cylinder and a bunch of copper pipes (all of which i kept) and disconnected the cold tank.

I kept the same radiators though and i dont know if you need a power flush (i did based on the amount of black stuff that came out ). It could probably be cheaper than what i got as i specced most of the parts myself and they were more towards the high end side.

Ah nice, that's cheaper than i thought. Thanks for sharing.

What boiler did you get?

MaxP779 · 11 Nov 2013 at 18:45

Rossi~ said:
Ah nice, that's cheaper than i thought. Thanks for sharing.

What boiler did you get?

Vaillant ecotec 831 boiler. Was thinking worcester bosch 29CDi initially but the stainless steel heat exchanger in the vaillants swung it for me, apparently stainless steel > aluminium which the bosch uses.

The other stuff was 6 drayton TRV4's and a fernox TF1 compact filter. I left the shower and thermostat choice up to them, ended up with danfoss TP5000RF Si thermostat/programmer and a methven bar mixer shower, pleased with both.

Nightglow · 11 Nov 2013 at 21:37

Valiant has the edge over Worcester Bosch in my opinion.

Google, there are firms doing Valiant Combination Boiler Packs, comprising boiler, flue, stat & programmer.

http://www.plumbnation.co.uk/site/vaillant-ecotec-plus-831-combi-boiler-packs/

Participant · 11 Nov 2013 at 21:53

Just to throw it out there, is combi definitely what you want as opposed to unvented cylinder + system boiler?

Mickie · 12 Nov 2013 at 01:07

if you want to save on gas, dont get an unvented cyliner..

the boiler will constantly be on heating the tank even when you arent using it.. it'll loose upto 3kw a day in heat loss, which costs money..

buy a 28kw combi boiler and it'll do the same job, just not turn on randomly all the time..

Yaayuh! · 12 Nov 2013 at 08:18

Mickie said:
if you want to save on gas, dont get an unvented cyliner..

the boiler will constantly be on heating the tank even when you arent using it.. it'll loose upto 3kw a day in heat loss, which costs money..

buy a 28kw combi boiler and it'll do the same job, just not turn on randomly all the time..

Participant said:
Just to throw it out there, is combi definitely what you want as opposed to unvented cylinder + system boiler?

Yes, i am sure.

Nightglow said:
Valiant has the edge over Worcester Bosch in my opinion.

Google, there are firms doing Valiant Combination Boiler Packs, comprising boiler, flue, stat & programmer.

http://www.plumbnation.co.uk/site/vaillant-ecotec-plus-831-combi-boiler-packs/

Cheers buddy.