View Full Version : Central heating boilers. Advice please. (U.K.)

Noah Zark.
20th Apr 2009, 20:27
My fellow Prooners.
The possibility of having a new central heating boiler looms into view for Noah. The last person to undergo this ordeal that I spoke to (quite a while ago) says that condensing boilers were being shoved to the fore, but I have heard quite a few stories in the Caveat Emptor vein. I didn't know that there is now available a condensing combi boiler. So, any comments, advice, warnings, hints, tips, w.h.y? all gratefully received.

20th Apr 2009, 20:34
I have only had combi boilers these last 20 years and as long as it's a good make, Vaillant, Potterton, can't remember, and it's installed by British Gas or a recommended corgi accredited engineer, then hot water, heating and hassle-free living are yours.

I've just this last week had mine re-pressurised, which fixed an intermittant problem due to low pressure which can happen due to leaks, but mostly due to evaporation etc. However, 2 mins later back to better than normal. Unless you share with many users there's always enough water on-demand.

If you have a large property then there are perhaps other options that might do the job better and more efficiently with newer technology.



20th Apr 2009, 20:45
Condensing boilers are now mandatory in the UK.

If you are on gas, British Gas are as competitive as anyone and offer the benefits of a more comprehnsive guarantee and aftercare programme.
If it's oil then you have quite a wide range of options and the choice will depend on how many radiators you have or might need in the future, number of bathrooms and other outlets for hot water it needs to serve.

You can buy the boilers direct, but you won't save a great deal of cash if you factor in the time it will take you to install it and get it up and running. Some insurance companies have also started to exclude any claims resulting from appliances not installed by professional tradesmen.
Unless you really know what you are doing, get a CORGI registered plumber to source and install it for you.

green granite
20th Apr 2009, 20:53
Had a combie boiler for 25 years (a Worcester) replaced it with another Worcester condensing combie a couple of years ago no problems at all.

20th Apr 2009, 20:54
But be aware that "CORGI" is no more.

Since 1st April a new scheme named "Gas Safe" has replaced it.

20th Apr 2009, 20:58
Court a local plumber, (like 'our Trevor), and keep the boiler you've got.

The modern stuff has to be bled, tinkered with, and only lasts about 4 years before the b*gger breaks down and you have to get into some messy contract with British Gas.

Despite the promises of being an "A" rating, it won't save you anything in the long run. Or for that matter, the short run.

Either that, or claim income support,and get the local authority to install a log burner (European Grant) with a back burner.:)

Capt Chambo
20th Apr 2009, 22:07
If you go down the condensing boiler route just be aware that they can be noisy! I had a Keston installed as part of an extension some years ago, very efficient but a lot of induction noise.
Sold the place a few years ago so can't tell you whether it's still going!

20th Apr 2009, 22:29
I bought a Baxi condensing boiler about 7 years ago. Over the last year I have spent enough on it to have bought a new boiler and it is still not right. Baxi didn't want to know.

I eventually found a website and wished I had seen it seven years ago. It covered three years of serious moaning about Baxi and led me to believe that I have been very lucky.

I think it is worth paying a bit more for a good one like a Valliant.

20th Apr 2009, 22:53
On the basis that less moving parts is less to go wrong

The Atmos Intercombi HE 32 looks like the real deal

Atmos Heating (http://www.atmos.uk.com/product_group.asp?section=000200130003)

21st Apr 2009, 00:23
We are nursing a very old, traditional boiler. It's not condensing, and it has gravity feed hot water. It works flawlessly and has done for the last 25 years that we've been here. It wasn't new then.

I was warned that a condensing one will:
a) cost about 7k to supply and install because the gravity feed hot water will have to come out and all new pipes be installed,
b) last no more than ten years, and probably more like 8,
c) be about 5% more efficient than the old one, but more than offset those efficiency savings by the poorer life expectancy and the need to replace the hot water system.

Daughter has a condensing boiler that's 8 years old and on the way out (it has to be "repressurised" most days, too).

21st Apr 2009, 08:28
Had a condensing boiler in situ for the last year which replaced the old system of cistern/back boiler. Shop around for the system and installation. Worcester Greenstar has a good track record. Priming the system is no problem and any noise is usually caused by a loose panel or bad siting of the boiler. DONT entertain British Gas...rip off merchants! Likewise, dont enter into costly support contracts...shop around for a local. Just to add, we have saved money by changing the system...any system that has to be re-pressurized more than a couple of times a year has a fault which requires the attention of an engineer.

Scumbag O'Riley
21st Apr 2009, 09:41
I was warned that a condensing one will:
a) cost about 7k to supply and install because the gravity feed hot water will have to come out and all new pipes be installed,Sounds a tad high, though obviously don't know size of the gaff. We had a quote recently to do much the same and came in at 2k. After checking the prices of the materials inthe local plumbers merchant, and multiplying days worked by a reasonable day rate for a skilled tradesman like a heating engineer, it still came out a bit high. Not out of the ball park though. Some of these tradesmen don't realise there is a recession. I know my daily rate is being squeezed quite hard right now, and that concept will be passed onto what I pay if my suppliers want the work.

When calculating savings one also needs to factor in the cost of keeping a hot water tank hot even if the water might not be used. One of these new fangled combi boilers will only burn the gas when you need it. Even so, payback is not particularly quick, better to insulate the house me thinks.

21st Apr 2009, 10:02
Noah. I've been a lurker on PPrune for a while and at last may be able to contribute with something useful.

Take a look here -
MLJ Bryant, CORGI plumber, also known as Mike the Boilerman (http://www.miketheboilerman.com/)

I'm in for a new boiler too, this site at least gave me some idea what to expect when an Engineer came and started to explain what needed doing (flushing systems or not, radiator thermostats etc).

I've had a Worcester combi for 17 years, annual service, no problem (a surprise given that it was fit by a bunch of cowboys), anyway, I'm happy to look at a Worcester again.

I haven't had my quote yet - hold 'yer breath!

Noah Zark.
21st Apr 2009, 11:11
Thanks for the replies, folks. They seem to support my original thoughts so far, but any more replies welcome. Thanks again.

21st Apr 2009, 11:55
I live next door to a British Gas Engineer.

Both he and I have looked into replacing the old style large capacity tanks that we have in our properties with new, sleeker combi boilers.

Points to note. Because Combi boilers provide hot water 'on demand' they use a thing called pre-heat. They (combi boilers) can actually cost more to run than a traditional large tank, depending on how much water you use.

If you use a lot, combi may be the way ahead instead of heating large volumes of wate several times a day. (Upon advice, I have my water heater on once a day, for 30 minutes in the morning. This is more than sufficient to heat the water required for the whole day - 2 person household, one person at home most of the day.)

Another problem with changing is the gas pressure, or rather the bore of the pipes required. Depending on your current system, you may find that to install a new one, you need to re pipe the gas supply from the main box entering your house (not the right wordeology I know, but check it out).

I was going to go combi despite the probable extra daily expense of running it, just to gain some cupboard space in th eutility room. The pipe issue has put me off.

My neighbour, the heating engineer, has opted likewise.

Capt Chambo
21st Apr 2009, 13:02
If you haven't already seen this site it might prove useful....



Burnt Fishtrousers
21st Apr 2009, 13:28
Im the property I rent out ive an old faithful 20 year old Valliant that has has one or two replacement parts but is going strong.

The problem with condensing boilers is that the flue gases are at a lower temperature which can lead to condensate and back end corrosion of the heat exchanger...oh and the condensate formed has to drain somewhere sometimes into a soak away which is acidic..which if left to drain down the front of your Cotswold Stone house will erode the stonework.... so it needs proper draining

A storage combi will also have a keep hot facility which will cost more to run than a non storage type and will reduce the SAP rating of your property when you come to sell

In my house I have a Worcester Bosch which is very good and would cost about 750 to replace not 7K

If you are quoted 7K from a plumber ask him to itemise the bill, go on line and do it yourself ...and if its plastic push fit Hep 20 type piping it's a piece of Pi$$ to fit and far quicker than copper and Yorkshire fittings.

21st Apr 2009, 13:34
Replaced my 20yr old gloworm 14 months ago with a Potterton (same as Baxi now, I believe). Condensing boiler straight swap for non condensing, no change to existing heating and hot water system.

System went down last week. Turns out contacts on Flame failure device dirty. five minute job for man who fitted boiler. 30. Showed me how to do it myself next time. I Didn't need showing on the old boiler. I suspect that any savings on fuel use on this one are going to go on maintenance. It's got a PCB, a fan, and a condensate pump that the old boiler managed without. The old boiler was cast iron. This one is sheet steel.

I think I'm going to miss the old boiler.


21st Apr 2009, 16:45
Ours was quoted at 7k +/- 1k by three different firms. The reason is that it's a big house, and the hot water cylinder is in the upstairs airing cupboard in the middle of the house. The condensing boiler would have to go on an outside wall somewhere, and would need all-new pipes and cables to the cylinder - or an all-new system to deliver hot water to the various places in the house.

The old boiler is a massive cast iron thing that will go on for ever, until spare thermocouples and the like can no longer be obtained. We plan to nurse it along until we move to our "retirement home."

I'm a bit miffed that the government seems to want to mandate replacing that with something that is, overall, far LESS green. I'm sure there's more energy wasted in making and installing 3 or 4 condensing boilers than leaving one old one there. Maybe someone has some real numbers to prove or disprove the theory.

21st Apr 2009, 17:30
I'm a bit miffed that the government seems to want to mandate replacing that with something that is, overall, far LESS green. I'm sure there's more energy wasted in making and installing 3 or 4 condensing boilers than leaving one old one there. Maybe someone has some real numbers to prove or disprove the theory.

Bang on the nail Keef. The whole condensing boiler thing was/is all about market, like most things green/environment. In certain ideal conditions, they can save a small amount in energy costs. In practice it rarely happens. Like LPG for cars, if you buy one already installed and it's reliable, they're a benefit: not so quick & easy to recoup the cost if you're the intitial purchaser.

Rather than list the makes I hear to be poor from friends in the trade, I'll say the current consensus seems to be that Worcester-Bosch are about the most reliable. Not cheap though.

21st Apr 2009, 17:45
My elderly boiler (well, the c/h system) gave me a bit of trouble this year, but mainly due to medical problems which usually make it difficult for me to lay out flat to access the flame area.

Once I'd given the thermocouple a few wipes with an emery board (that gas is not the cleanest burning) and the sticky motorised valve had some exercise it was all good for another season.

I could get a new style boiler for around half retail from a good friend, but too many people have told me to stay with what I've got.

21st Apr 2009, 18:19
I believe for about 7K you can get a ground source heat pump which will pay for itself over the years.

I've just had mine replace (for a condenser - I couldn't afford the 7K) but the one thing that pissed me off was all of them quoting for a power flush of the existing system. "You've got to have that done other wise the warranty will be invalid..."

Fair enough, but when I enquired why it was going to cost 600 they went into great lengths to say that they have to do one radiator at a time and it willl take all day etc. Again fair enough, but when asked if this would be done after fitting the boiler they said that "No, it'll be done at the same time".

"So if I'm already paying you a labour cost, why am I paying another one to do the power flush?"


"I'm paying you to be here all day to fit my boiler. What costs 600 to do a power flush. Isn't it just a few pound worth of chemicals that is pumped round?"

"Oh yeah, but we have to go around all the radiators, opening and closing them"

"But I'm already paying you to carry out work here"


No one could fathom out that they were double charging. Several of the people who quoted tried to justify it by saying "Well we're a lot cheaper than British Gas".

The best advice I got though was to fit a magnetic debris filter. They are around the 100 mark but will put years on the life of the boiler.

Noah Zark.
21st Apr 2009, 19:03
Yep, I'm not liking the stories I'm getting. The thing is, my existing boiler, a Potterton Puma Combi, is fine. But it is not in a good place in the house. We (foolishly, as it transpires) had it fitted in the front bedroom of our house, when & where the old immersion tank and associated sundries came out.
Unfortunately, all of this is diagonally opposite where most of our hot water is needed, in the kitchen.
The result is that whenever you want to run a sinkfull of hot water in the kitchen, the boiler is running a long time, wasting water and gas, before the water in the kitchen sink is hot enough for whatever. It seems that if this boiler is taken out of its current position to move it to a place where it would be far more efficiently used, nearer the kitchen (Lord knows where as yet, that's the next problem!) it might by law (Don't know for sure, still trying to find an unbiased answer to this) have to be replaced by one of the accursed condesificators, which I cannot get enthused about!

21st Apr 2009, 20:39
NZ, my dad's a central heating engineer, I'm speaking to him later, I'll ask him then, see what he says.

EDIT: he's not absolutely certain, but says that the old boiler may well be condemned by whoever is asked to move it by virtue of its age/condition, or possibly by the fact that the flue might no longer meet regulations or be convertible to a fan flue.... Difficult to say for sure without seeing the installation.

Noah Zark.
22nd Apr 2009, 01:21
B & T's,
I was afraid that was the case, I kind of suspected it would be. Thanks anyway. N.Z.

Scumbag O'Riley
22nd Apr 2009, 11:05
I still fail to see how 7k is a fair price for replacing a boiler and putting a few pipes around the house.

The most expensive boiler on screwfix is 1004 (used screwfix as easy to get price). Flue kit maybe 100. 22mm copper tube is 2.50 per metre. A power flush machine costs 70 to hire. Bits and pieces cost a few pounds here and there. OK, lets say materials are 2k and with the info given I'm being very very very generous here.

So that leave 5k, lets say 4400 before VAT, for labour. If the plumber has a lad he will be on bugger all, minimum wage doesn't always apply to appentices. How long is it going to take? Is this 4k for a weeks work?

And if the quotes are all very similar than that is suspicious to me.

cockney steve
22nd Apr 2009, 13:43
Recently (18months ago IS recent, in 62 years :\ ) I and a friend were faced with a similar problem.

determined the existing back- boiler was combusting cleanly, no leaks anywhere....sprayed the old radiators with standard white-gloss paint, extended the system to upstairs (there was only a rad in the bathroom)...rerouted pipe-runs to shorten and tidy-up ,lagged all underfloor pipes (just used ordinary fibreglass loft-insulation, tied with "garden wire" )

Result:- lovely warm house, domestic hot water will still be warm about 2 hours after the tap was last used :) cost was less than 300 including 2 large radiators and one small one and all new rad-valves .

As others have stated...a condensing-boiler will cause failure earlier...because it is pressurised,internally,which quickly finds any slight leak or weakness.

A condensing boiler does NOT reach maximum efficiency for most people who use it a couple of hours in the morning and 5 or 6 in the evening...mostly the saving is minimal.

Cost of repairs is considerable, there is NO "routine maintenance"-It's a CON.

Failed/faulty parts are replaced (if you can get them)

Stick the dosh into a good investment (well, in better times :O ) and the interest will probably pay the difference in fuel costs....meanwhile you'll save the planet producing a new disposable boiler every 10 years or less.

Remarks about condensate are correct....sulphuric acid, helps sell a new boiler sooner than the punter hoped, has to be piped away...hope your drains can cope!!!

The guy next door had the same setup,but the flue got partially-blocked.....he got conned into a full system and, because the house was a bugger to work on, the bill went WAAAY over the quote.....works well, buthe'll never see a return on his "investment"

IMHO, ANY "energy-efficient" stuff is a big marketing swindle and that includes the glow-worm bulbs and the home-windmills that are guaranteed 10 years, but even under ideal conditions ,would take 30 years to repay their purchase-price.


22nd Apr 2009, 16:03

Entirely agree, but it's becoming difficult, The Maclaren gas valve that mine uses has been obsolete for some time. You can still pick them up (at a huge price) and a little bit cheaper on eBay, but who wants to shell out for something they may not need?

Likewise, I can see thermocouples disappearing soon, although don't mind holding one or two spares of those.

22nd Apr 2009, 20:54
What do you do if your boiler plays up?

Give her a slap and tell her to get back into the kitchen.....

22nd Apr 2009, 21:30
We've had a Potterton combi boiler for 11.5 years now (pre-condensing). We took out the water tanks in the loft and the hot water cylinder and installed new pipework throughout most of the house when we rebuilt the kitchen and bathroom and had front and rear extensions built.

It's been pretty good, although I reckon we've paid about 175 per year on average for servicing and replacement parts. It's broken down maybe 3 times, but 2 of 3 have been an electronics failure (requiring new PCB), once (most recently) it has required a new fan.

I only have to check the pressurization once a year (in the autumn).

It can be a bit noisy - mostly casing rattles rather than a fundamental combustion / pump noise.

But not having water storage in the loft makes up for a lot - some neighbours had their pipes freeze and burst last year when they were away and the resulting water damaged large quantities of the house, and destroyed ceilings, floors and carpets, decorations and furnishings that they had not long installed, having recently moved in. Ouch.


Sir George Cayley
22nd Apr 2009, 22:01
British Gas? They should wear spurs and a mask! Had a guy here this week to look a strait swap - old 25Kw combi for new equivalent.

He did a pastiche of the last century double glazing salesmen, down to the extra discount if you order this week, nudge nudge:=

He suggested a Worcester Junior at a cost of......................

now brace yer selfs.........

FIVE THOUSAND POUNDS:uhoh::uhoh::ugh:

as they are about 800 trade, I asked where the other 4,200 came from. The smell of bullshit wafting out of his mouth made me retch. Although I said " Well, thanks for coming over" what I really wanted to say was "What effing planet do you wake up on?"

I would ernestlyy recommend anyone thinkng of BG for a quote to save their time and effort. Local plumber popping round at the weekend - I'll let you know.

Sir George Cayley

Noah Zark.
24th Apr 2009, 15:59
Thanks for the input & info, folks.

24th Apr 2009, 16:22
If you need anything for a boiler/heater etc, try link below. Manuals, Installation, Exploded parts diagrams.

PartsArena (http://www.partsarena.com/baxi/)