/ Home & Energy

Boiler trouble? Our cameras reveal the truth about repairs

Boiler broken down? About to call an engineer to get it fixed? When they put away the toolbox, how do you know your boiler’s been correctly repaired or you’ve been charged the right amount? We went undercover.

Everyone’s winter nightmare is that their boiler breaks. Our boiler went last year – cue electric heaters, lots of blankets and, yes, occasional trips to the pub to keep warm.

Fixing boilers can be expensive and it’s also crucial that it happens fast – so the cards aren’t exactly stacked in your favour. If the guy (or girl) fixing my boiler tells me it’s the valve, or the printed circuit board, or the controls, how am I going to know if they’re right or wrong?

Which? goes undercover

With this in mind we decided to go undercover here at Which?. We invited ten engineers to service a gas boiler to which we had introduced a minor fault and watched their job with hidden cameras. This was a fault that should be fixed during the service at no extra cost (we basically disconnected a lead which stopped the boiler from lighting – a five minute job). So, how did they get on?

Two engineers suggested that we needed expensive repairs when we didn’t. One independent engineer said he wasn’t sure what the fault was – he thought it was either the board or the gas valve, with repairs predicted to cost around £500.

Another said it would be at least £200 for the part but suggested we might be better off getting a whole new boiler. We also found that two others missed key checks when trying to service the boiler. So not only are some of these engineers suggesting expensive, unnecessary repairs, others aren’t carrying out basic checks.

Do you need boiler breakdown cover?

We’ve passed our findings to the Gas Safe Register and it said it will investigate any potential safety issues.

But we didn’t stop there – we also looked at whether it would be a good idea to get boiler breakdown cover. We found that cost-wise most people wouldn’t save money taking this out. This is because the average spent on servicing is £75 and you probably won’t need repairs.

However, we also know that most people who have boiler breakdown cover do so for peace of mind, so we surveyed Which? members to find out who’s best. You can read this in more depth in our boiler contracts review. Let’s just say than one boiler servicing company got a much higher customer score than the others in our survey.

So, if you have boiler cover, do you think it’s worth it? And if you’ve ever had your boiler serviced or repaired, did the engineer do a good job and charge you a fair price?

Mike says:
25 August 2011

I have had my oil boiler serviced for a number of years by a qualified boiler man. After watching him do the job a number of times I decided to tackle the job myself last year and found the baffles and water jacket were so thick with hardened soot that I had to use a small air hammer to remove the crust before the baffles could be released. It then took nearly half a day with a pneumatic chisel to descale the water jacket and baffles.

I contacted the professional!! Engineer and told him what I had found and he said this was quite normal after a year. It is strange I had never seen him remove the baffles before!

I have just carried out another annual service and there is hardly any deposit on the baffles or water jacket proving that he had never serviced it properly before.

I would recommend contacting your boiler makers and find out from them exactly what the annual service should involve and then watch carefully to make sure the work is carried out properly.

Adam says:
25 August 2011

The problem is we all fight over prices and compare everything and want to go for the cheapest … Consumers don’t like paying for services – they’d prefer to spend £1000 on a new boiler and think they’ve a nice shiny bit of kit (which will probably only last 5 years) rather than spend a few £00 maintaining their old one.

Just a shame that there aren’t more people willing to understand things and get their hands dirty. A sign of the times we live in I guess.

gas brains says:
15 November 2014

no don’t.

Eddie R. says:
25 August 2011

To Mike.
Tread carefully Mike, as legally I think it has to be a ‘Competent’ person who carries out work on a gas boiler and your previous gas engineer could possibly drop you in trouble out of spite.
My gas engineer says I would need to be registered as ‘Safe’ with the proper control authorities to work on a gas appliance which he says is a legal requirement.
You are also not able to test for spillage without the proper test gear.

gas brains says:
15 November 2014

yes,always use a competent engineer,you know,the out of work,ex squaddies,dog walkers,anyone really,read your books,pay three grand and as if by magic you emerge a gas man,easy.

gas brains says:
15 November 2014

the proper control authorities,dont forget them,gas safe,part of capita,you know the congestion charge people,no bull s t there then.

Chris says:
31 August 2011

My Ariston Combi Boiler started giving some grief. Basically, when the heating system was activated, the boiler fired up, but after about 10 secs it died. The hot water system worked perfectly well.

An engineer from a reputable (??) property maintenance company attended, and decided that the PCB and flame probe would require replacement. Including his emergency callout charge of £120, and new parts + labour, the total bill was likely to be over £600.

I was unhappy with his diagnosis; he had not noticed that when the heating came on, the pump worked, and some warmth extended along the CH flow pipe from the boiler, but the rads did not heat up at all.

In short, I removed the actuator from the top of the diverter valve, discovered that the valve pin had become stuck, and sorted it it with 2 squirts of WD40 and a piece of kitchen roll to mop up.

Not impressed with the engineer, and company cancelled the call out charge.

You might be best to replace the valve before winter and providing you know how to drain the CH system it is not difficult. Replacement valves are readily available and I picked one up in a large B&Q.

Even if you have jobs done professionally, try to do the diagnosis. It could save a fortune.

Eddie R. says:
31 August 2011

In the course of my job, I have dealt with dozens of Plumbers and many of them dabble in central heating in spite of no formal training in the safety aspects of gas boilers and all they have is the very iffy status of being ‘Gas Safe’. Modern boilers have complex electronic control systems built in and without the proper test gear, spillage cannot be detected and the ‘Have a go Henry’s’ are legally allowed to throw boilers up on someone’s wall and run like hell. The real skill is diagnostics in fault finding, but sadly the Yellow Pages can only place them in alphabetical order as opposed to competence in gas boilers. Electrics and Plumbers don’t mix well, as I know of one who installed a bathroom power shower and instead of wiring the 240Volt cable to the mains, he sent 240Volts up the 12Volt cable in spite of the cables being clearly marked ‘240V’ and ’12V’.

gas brains says:
15 November 2014

you sir are totally correct,anyone got a spare vc.

R.A.Jordan says:
1 September 2011

My boiler broke down 2 days before last xmas,I called british gas as I had a service contract with them,they came xmas eve,I explained that if you turned off the electicity to the boiler and then switched it back on and fired up the boiler it worked,but once it shut down at the end of its cycle it would not fire up again.the engineer took the cover off,did what I had told him,put cover back on and went to leave.Isaid to him that he had done nothing to fix the problem and I would be back on the phone once the boiler had gone through its cycle as it would not fire up again,when I rang them again I had to make another appointment after the xmas.When the engineer came I said that it must be something wrong with the curcuit board,he said it needed a new spark generator and igniters.Between 28th dec 2010 and the 4th feb 2011 they replaced 4 items and the boiler still did not work, they did not check the curcuit board,in the end I got fed up with the service I was getting and the missed appointments and cancelled my contract with them. I had a private engineer in and he told me that the fault was probably the curcuit board as I had said,in the end I decided to have a replacement boiler.The 1st engineer told british gas that he had defrosted the condensing drain pipe outside the 1st time he came,I told british gas this was a lie and I would say that to the engineers face,nothing was done about this.

Mervyn Rolls says:
1 September 2011

I have experienced bad boiler servicing. But first why are these servicemen/fitters called engineers? The dictionary definition of an engineer does not cover them. Secondly why is the service schedule the same whether there is one person per house or several, small house or large, irrespective of the hours of boiler use?
In May 2010 my Glow-worm gas boiler stopped working. I rang Glow-worm, and their charge for a serviceman was £250 just to ‘ring the door bell’, with free parts. So I contacted the gas supplier, Phoenix Gas. Their serviceman incorrectly diagnosed the diagnostic panel read out of F12 as a faulty control panel, cost £300, and advised I got Glow-worm out. Their serviceman correctly diagnosed a fault with the flow sensor, a part which can be purchased on-line for about £75, even though it is just a plastic nozzle with a spade terminal.
So I have taken issue with Phoenix Gas that they are in breach of the Sales of Goods and Services Act by not dealing with the fault, and requesting that they compensate me. So far correspondence has flowed to and from, in which Phoenix Gas will not even accept that their serviceman got it wrong. Fortunately I have changed my gas supplier to the only other in Northern Ireland as yet, which gives me some satisfaction. My next stage would be to contact Trading Standards, but why should I have all this hassle and expense because of a serviceman’s incompetence?

PaulG says:
1 September 2011

I am 65. Years ago in my youth (and actually up to my 30’s), I would happily work on cars, house electrics, replace a kettle element (when you could buy them) and indeed wired my Victorian house from scratch (ie not just re-wired) and dealt with all sorts of things that are now considered too complex for the ordinary man (or woman). I also designed (with the help of a book) a new central heating system, including calculating radiator and boiler sizes, and then bought everything ‘off the shelf’ (before the days of the Internet) and fitted it on my own, including learning to bend and solder copper pipes and do all sorts of plumbing jobs like fitting taps and showers.

Nowadys sadly, everything is almost too complicated (or indeed illegal) for the average DIY-er to do. I open my car bonnet and am faced with a mass of wires and plastic covers all bulging out at me. Irons refuse to let you open them to clean the scale off so we end up buying another. And boilers, are now so complex that many so called ‘engineers’ are unable to trace faults on them.

Oh for the days of simplicity. And yes how come that anyone who can wield a spanner feels able to call themselves an Engineer. Servicemen or fitters is fine as Mervyn says.

Not only is ‘stuff’ complicated now but many young lads are growing up without male influence and even where this exists, many of the generation after mine won’t or can’t have a go at practical projects. Instead they spend their spare time on the computer (like I’m doing now!)

Sorry if this is a grumpy old man whine. I feel better now!

There is legislation for our safety, and some things are much more complicated than they used to be, but others have not changed and there is much that you can still do yourself. There is a lot of useful advice on the Internet. A lot of this is not very good, but it is probably no worse than taking advice from friends and neighbours in the days when most people were prepared to have a go themselves, often because they could not afford to seek professional help.

gas brains says:
15 November 2014

this electronic age will die a death,people will stop buying,its a punch in the face age,you can only take so much and the human eventually gives in,manufacturers must realise this techno war must stop.its company last man standing,my nuts are bigger than yours mentality.were stuck in the middle.

gas brains says:
15 November 2014

legislation is not about safety,its profit.why would a gas engineer go to a carbon monoxide report with no personal carbon monoxide detector,might as well send him to dachau.nice little town actually.

gas brains says:
15 November 2014

I meant to add,a national grid engineer.

Eddie R. says:
1 September 2011

Sadly, this is the age of the ‘Condensing Boiler’ as recommended by Gordon Brown in his bid to save the planet and I was told by a very competent central heating engineer, that they have a life expectancy of 5 to 7 years thanks to their complexity. Did Gordon not also encourage the new mercury filled light bulbs?. Did Gordon EVER get ANYTHING right?.
Fortunately I managed to get the last of the conventional combi boilers fitted before the condensing variety were forced down our flue’s. Incidentally, experts have established that the mercury bulbs are a hazard, but will Brussels change it’s mind? Ask a flying pig.

Yes, condensing boilers are unreliable, but it’s due to poor design (and sometimes poor installation) rather than any fundamental flaw. Circuit boards – a common weakness – should outlast the boiler. Anyone with experience in electronic design and repairs will confirm that consumer goods are made cheaply, with a result that they are unreliable.

If manufacturers are going to turn out unreliable boilers then we should be pushing for much longer guarantees. If a manufacturer has to provide a long guarantee, the quality of their product is likely to increase dramatically.

5 years ago we had a Worcester Bosch condensation boiler fitted and it has reduced our consumption of gas. Last December during minue 10 degree weather the boiler controller burned out. Through our Nationwide building and contents (B&C) we have 24 hour emergency home repairs and they proved to be slow and inept showing up twice (yes twice) with the wrong parts and taking a week to repair a simple task. They argued a week was OK because it was a cold snap and they were busy so hope that your boiler breaks down during a hot spell. They gave us £50 for our frustrating and very cold run up to Christmas. Needless to say we have just moved our B&C to John Lewis Insurance because the premium is less by £150 a year, the emergency cover is £1500 (not £500) and we also get several other benefits.

gas brains says:
15 November 2014

still the same engineer,dodger.

Cathy says:
5 September 2011

I had to replace a 4 year old Gloworm boiler recently. It had been serviced annually by the local plumbing company that had installed the boiler. Unfortunately the silicone seal on the casing perished causing the boiler to burn its own components! Gloworm changed the seal in all new boilers prior to my fault due to these type of problems, but because my boiler had not been serviced by a Gloworm engineer they would not pay any compensation. I had to spend £1700 on fitting a new boiler. Do not touch Gloworm with a barge pole. Rotten company rotten product.

P.F.Ratigan says:
7 September 2011

I had a 20 years old boiler that I changed for a British made condensing boiler. When it stopped working after a couple of years the serviceman worked his way through the boiler changing parts until it worked again. The cost was exorbitant, so after it happened twice I again changed the boiler, but this time to a cheap old fashioned once through type. I thought that if I had problems then it would be easy to fix. When it stopped working after a couple of years the new serviceman worked his way through changing parts until it worked again. This time it cost me two thirds the cost of a new boiler.
Despite being recommended by the manufacturer neither serviceman knew enough to diagnose the faults.

gas brains says:
15 November 2014

no one does.

During the minus 15 pre-Xmas freeze last December our 4 year old Worcester-Bosch condensation boiler blew a control board because of a power surge (our neighbour’s went as well). But we had 24 hour Emergency Home serve cover through Nationwide B&C insurance and thought all would be well. How wrong you can be. They (a) took a week to fix it, (b) showed up TWICE over 7 days with the wrong parts, (c) argued it was a difficult time with so many breakdowns happening at once, and lots more excuses I will not bore you with. We complained in writing and got a £50 cheque which we spent at the local Loch Fyne restaurant. We also voted with our feet by switching emergency home cover to John Lewis Insurance – they have no limits on call-outs and cover 3x as much for less premium. Always shop around, and always have space fan heaters, electric radiators, electric blankets, jumpers etc in your house just in case.

Claymore says:
3 April 2012

As far as I am aware, ‘Gas Safe’ is only a registration procedure but it doesn’t make a gas fitter capable of fixing a gas boiler, so it really comes down to experience and ‘Gas Safe’ only allows a fitter to work on a gas appliance irrespective of competence. It took Scottish Power about two weeks and three different engineers to diagnose the fault in my boiler, but they were ‘Gas Safe!’

Andrew Moody says:
18 April 2012

I have three houses, two rented out. Each has a Combi Boiler. Over the past 15 years I have never found a service Engineer I can trust. The main problem is the boiler being sabotaged ( eg. disconnecting a wire) so that I call back the engineer to carry out unnecessary work. This problem seems endemic. Gas Safe/Corgi or whatever all seem to have the mentality of cowboy builders. There is also a problem with Insuring your boiler for breakdowns since there are a limited number of engineers but more companies offering a breakdown service so inexperienced engineers are sent out and produce shoddy work. I have recent experience of this. These same engineers, I have been advised, also work on Gas critical parts !. I have been forced to cancel my cover from Breakdown service companies and am still trying to find a safe, experienced, trustworthy plumber/engineer.

Isn’t the real problem with British Gas engineers the fact they have to make a certain numbers of calls a day, averaged over a certain month period, so there are likely to be times when they’ve under pressure to finish a call ASAP, hence saying you need a new boiler will get them to the next call quicker? Targets are a wonderful thing when used properly and sensibly otherwise they’re just a farce.

Maggie says:
10 May 2012

Our boiler broke down at the beginning of February, and our usual plumber tried to repair it but eventually told us the part was obsolete because the boiler was too old. We decided to get at least three estimates to replace it , including this plumber, whose estimate came in at £3438, to include extra radiators. The second plumber was from British Gas, who hardly looked at the boiler before saying it was irreparable , and estimated £6023 for the same job! The third plumber messed around for ages looking for a separate pump , but eventually said ( when we told him why we were replacing the boiler) that there were heaps of parts still floating around for this boiler, and if we liked , he’d try and repair the old one! In a few days, he’d ordered the part for £140, and the total bill came to £391 – a bit steep , I thought – so thank goodness we asked him for an estimate! Incidentally , he says this is the main cause of breakdowns with this type of boiler , and it should go on for a long while yet! I know it’s over 30 years old , but our gas bills are cheaper than our neighbour’s and several friends’ who have all renewed their boilers in the last few years, and that’s good enough for us! We’re pensioners who don’t qualify for any help with the cost of renewal, so we’ll go on hoping this one will last, and we’ll manage without the extra radiators for now!

Charlie says:
15 July 2012

Make sure that the gas engineers are licensed and only hire your trusted Gas Safe Engineers so you won’t be overcharged for repairs or part exchange

There are good and bad engineers. Have a look at last year’s Which? report on boiler servicing and you will see examples of overcharging.

Gordy says:
10 January 2013

Have had a Glowworm Fireblaze fire with back boiler in our grate for 20 years, with British Gas annual maintenance contract from Day One. Annual service -previous one was 16 months ago-revealed minute cracks in front fire burner part. Fire had been working satisfactorily and apparently normally until the serviceman called. He pronounced it unsafe and disabled it from working. The boiler for hot water and heating radiators is still working. A replacement burner unit for the fire is not available (obsolete) from BG, but some seem to be available on the Internet. I query how the burner unit came to develop the cracks, whether they were there before the service visit and can`t help but feel a suspicion that they maybe weren`t. From that, I speculate as to whether they were caused accidentally or maybe deliberately in view of the age of the installation and BG`s policy of using service employees as salesman for replacement boilers. The small grilles in the burner where the gas emerges to produce the `living flame` look to me, in two cases, to have a tiny bar bent out of true and it`s above these little grilles that the cracks appear. I could imagine the damage being caused by the head of a screwdriver inserted and gently levered to produce the distortion and cracks….. Of course it could equally be that I`m somewhat paranoid……

Odd you should mention this: a few years ago my late neighbour had her annual service for her gas fire / back boiler unit, and the day after nothing worked. She asked me to pop round and have a look and I found that the fuse had blown in the power supply. Put a new fuse in and it blew with a bang straight away. She got BG back and would you believe it, the mains electric cable to the boiler had been put back draped right over the main burner, so as soon as it came on in the morning it burnt the insulation off the cable and shorted out on the burner. Engineer mended it all OK but then started pestering her (and 86 year old widow) to have a new boiler. Oddly a few days later she started getting letters and adverts from them in the post too, and she did (sadly in my view) agree to buy a new boiler, which clearly was not needed at all.

Gordy says:
13 January 2013

Well,Dave, your elderly neighbour`s case is a horrendous example of bad service, but at least it was plain what had caused the problem. In my case the cause is obscure, although I may contact the technical dept. of the manufacturers to get their opinion/suggestions. Whatever transpires I think I shall move my contract from BG and may change to a different supplier as well.
I just have a hunch that all is not as it should be and feeling that way makes it difficult to continue a working relationship, although it could of course result in an `out of the frying-pan, into the gasfire` scenario. I am now awaiting a plethora of phone calls,letters and bumf about new boilers, if the experience of your neighbour is any guide!

Daniel Tissinngton says:
3 March 2013

I can explain why the gas boiler service is generally not satifactory. A gas boiler is a fairly straight forward electronic device & plumbers are not trained to understand electronics. Some don’t seem to understand plumbing either. For example, water pipes should incline toward an air vent & water pumps should be set to the slowest speed that provides adequate water circulation to avoid air bubbles!

Furthermore, the priciple of the condensing boiler’s superior effeciency depends on cold water being returned to the device. In small household installations, this requirement is not met. Just feel with your hand the temperature of the return water pipe at the input to the boiler. My return flow is very warm/hot duing the time the heating is ‘on’ except when the applience is first turned on. .

Government regulations are written by Bureaucrats & enacted by MP’s, who in general, won’t listen to reason & backtrack! Thats why WE have got ‘messed up’ global warming regulation ….a matter which is proving prohibitivley costly in finacial terms & will cause untold misery/disaster for humanity when the Ice Age returns.

.Detailed reasoning for this statement & prediction in para:3 above can be found in ‘International Political & Environmental Folly’ which can be downloaded on Amazon as an e book or obtaied as paper back version from Publisher Rosedog of Pittsburgh USA

Daniel Tissington!