Looking at replacing an original circa 1985 G rated boiler (with storage tank) for a combi.

Considering replacing the radiators (8) also as I assume there have been design improvements since then. Most of them don't have fins on etc.

Any makes to go for or avoid? Any idea of cost?

Looked at a Worcester Bosch Greenstar cdi(?)

Also I think most of the rad pipe work is micro bore - is this going to cause a problem?

Just about to go and check if the gas supply pipe is 22mm - does it definitely need changing if it is 15mm?

It's a small ish 3 bed detached house.

Considering getting British Gas in just for some feedback and ideas / checks then getting an independent to do it.

The house is tenanted and apart from this week I am 4k miles away so apart from measuring up etc I won't be able to save money by doing any of it myself.


Thanks in advance for any advice.

[Edited on 1/1/13 by hobbsy]

Just making sure I get notifications

Dont use BG, they're expensive and no guarantee of a good job. Do you know any good gas installers in the area of the house? Or, tell use where the house is and maybe someone can recommend.

Greenstar is a popular boiler. Im pretty sure that all combis need 22mm feed.

Your existing microbore might be quite smeg'd up, but it could also be quite a messy job repiping the full lot.

I found the cheapest option was to buy the boiler and then pay for a days labour to have it fitted, paid £300 for the labour and a few extra fittings and £750 for a biggish Valliant boiler and new control unit, all in about £1100, bit better than the £3K BG wanted.

I got one of these last year, it's been fantastic.

Potterton GOLD 33HE Combi Inc Std Flue & Clock

And here's the place it came from, easily the cheapest I could find and radiators in there packages are very good quality.

http://www.mrcentralheating.co.uk/the-boilers/boilers-by-brand/potterton-boilers-and-accesories/potterton-combination-boilers/potterton-titanium-33-he -with-free-std.-flue-clock?cPath=213_209&

Modern condensing boilers have a very fine matrix in the heat exchanger so retrofitting to old dirty rads can and probably will lead to issues as this gets blocked.

The boiler is very quiet, and delivers a full force shower that you have to mix cold with, having had a smaller combi before big is best.

I found a chap that would verify and sign off for £100 so installed myself, most corgi plumbers also want to mount the boiler, if they provide the boiler expect to pay £2000 for the same item we had quotes which were massive !

Regards Mark

[Edited on 1/1/13 by mark chandler]

quote:

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Originally posted by zetec
I found the cheapest option was to buy the boiler and then pay for a days labour to have it fitted, paid £300 for the labour and a few extra fittings and £750 for a biggish Valliant boiler and new control unit, all in about £1100, bit better than the £3K BG wanted.

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We had a Vaillant fitted with our extension, I'm afraid I can't remember the cost but it wasn't considerably more than the others. We've had absolutely no trouble with it, our annual service consists of 'cover off, quick look, cover on', compared to our previous boiler which warranted an almost complete strip down and rebuild just to keep it running.

If it's 15mm unless you fit a stupidly small boiler I think you'll need to change. I fitted a WB 30cdi (well I did all the work and just got a gas man to solder up the pipes and nip up the nuts and sign it off) and he insisted I go for 28mm pipe on the basis that the boiler was in the kitchen and at some point someone might want to fit a gas hob so makes sense to cover both a boiler and a gas hob. He said that if it was definitely just the boiler I could use 22mm but going smaller would cause problems. I'm sure somewhere there's equations for flow rate, pipe length, boiler consumption etc but that's what he said anyway....

I've got a 30cdi, installed it with the help of a gas fitter mate about 5 years ago, and it's been golden. Coupled it up with a Worcester wireless programmable room thermostat and it's excellent. We did have to upgrade from 15mm to 22mm gas. I did find that as I replaced an old conventional system, with the combi running at higher pressure, it blew a couple of pin holes into one of the old rads.

Just had a Worcester Bosch Cdi fitted by British Gas. We had a couple of independent quotes and BG were about the same, but the BG quote is fixed price and as its an old house we went for that expecting quite a bit of extra work.

The chaps who did the work were very good and it all works fine. They were very keen to involve us in siting etc and replaced a few old valves and pipework for us (and yes you do need a 22mm gas pipe). Boy they drank a lot of tea!
Got remote wireless thermostat and controller (same cost as standard) so can alter the temp and turn on/off etc from the computer or away from home over the internet or by text. You get a years worth of BG homecare which seems good.

Just be careful with the salesman. e.g.:

BG offer a 1% per month finance package which were told we could pay off at any stage without charge - now find they want 50-something days worth of interest if we pay off the balance in a oner. We switched to BG as the supplier as it included £200 rebate and included free smart meters (which will apparently be compulsory before too long, supposedly at a cost of £700-800) but which we now find are being fitted for free anyway. Intend to switch once the meters are fitted and the rebate is in. Customer service so far is pretty poor.

It seems I had the same package as Geoff. Had numerous quotes and went for BG, not the cheapest and not the dearest but very professionally fitted.

Generally 22mm would be the minimum gas supply needed.

If fitting a new boiler onto an existing heating system it is importanat that the system is cleaned thoroughly before the new boiler is connected, the waterways in plate/plate heatexchangers a very small and it does not take much to block them, diverter valves etc are also very easily trashed by dirty systems.





Consider fitting a magnaclean filter (about £80) or similar for extra protection of your new expsive boiler.



Don't assume that a Gas Safe registered installer will giarantee you a good job, Gas safe only relates to gas regs, it doesn't relate to the wet side of the installation. The chartered institute of plumbing and heating engineers, register people as registered plumbers and also as registered heating proffesionals, it might be worth checking out their website. You can also ask you're local trading standards.

Be carefull about the years free homecare from BG, it is generally less than you would be getting from a decent independant installer anyway. For as long as I can remember Worcester greenstars (cdi and si) have come with a 2 years parts and labour warranty from Worcester. and for the last 6 months or so they have come with a 5 year warranty as standard. I am a Worcester registered installer and when they came with a standard 2 year warranty ours were extended to 5 years, and now that they are 5 years as standard ours are extended to a 7 year warranty from Worcester. you could look for a worcester registered installer.

When considering the size of your combi, even the crappiest 24kw boiler from one of the diy sheds would heat the house, your main consideration should be your hot water requirements. Generally we recommend the 38cdi classic to most people in semis or if on a budget the 30si.

[Edited on 2/1/13 by rotax78]

I fitted a vaillant 8 years ago in our house. Just topped the pressure up 3 times (not a lot each time either) over the 8 years, never been touched apart from that.
Potterton in a conversion 9 years ago, needed a pcb after 18months, but fine since.
WB 24ijunior fitted 3 years ago. Had a leak a couple of months ago, and just started leaking again. May be fitter at fault (not me this time, the others got certified but I fitted)

The 24i is in a 5 bed rental, 2 bathrooms one of which is bath with combi-fed shower over (the other leccy shower, ideal for times like now when the boiler goes down)
Plenty of heating for the rads, enough hot water supply too.
My place the combi is the bigger version of teh vaillant, bath runs reasonably fast, and we have an excellent shower in the en-suite

However, for a rental, I would get the cheaper one and spend the difference on something more useful to me. Would buy vaillant again I think. However, boilers often have a kickback to installers, so many only want to fit their preferred make (ie ones where they get the best kickback)
I would seek recommendations from locals to the area if at all possible.


As to rads, worth changing if not too expensive, otherwise they will need a good flush. Also worth fitting a magnaclean. Collects lots of crap if you re-use the rads (even after a powerflush) though in my house with all new rads and plastic pipework it is still pretty clean after 8 years. But can save on bills so on balance I would fit one.

Having been involved in some of the DECC stuff over the last couple of years, don't pay for a smart meter. If they become compulsory, it won't be down to you to foot the cost directly.