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Boiler servicing investigation expert: ‘I was stunned’

The experts who helped assess how well engineers serviced a faulty boiler were shocked to see most failing to meet legal requirements. One expert, who wishes to remain anonymous, shares his thoughts.

I have been in the gas industry all my working life and have gained more than 40 years’ experience. I am a qualified tutor, assessor, internal verifier and a quality consultant.

When I was approached by Which? to work as an expert, I felt confident I would find the majority of gas engineers to be competent due to the rigorous training and high standards that are expected within the gas qualification, with competency checks every five years.

So I was stunned to witness 10 supposedly proficient engineers carry out a service of a simple central heating boiler, where not one completed this task correctly. In my opinion the services were not carried out to the manufacturer’s instructions and the appliance was not left in a safe working condition on most occasions.

Poor knowledge of basic gas safety

Leaving a boiler over-gassed, and not confirming the case seal is intact are both, in certain circumstances, potentially unsafe – leading to a serious situation.

It was clear that some of the engineers had little understanding of the concept of how to service a boiler or basic gas safety, and when carrying out a flue gas analysis test did not seem to understand the findings.

In conclusion, I have to ask why the knowledge and understanding was so poor. Could it be that the engineers are under economic pressures to complete the job quickly – or is it that training is not consistent throughout the United Kingdom?

Have you been surprised by the standard of work done by a boiler engineer?

You can read the results of our boiler investigation online or in the September 2015 issue of Which? magazine. We shared our findings with the Gas Safe Register, which has promised to look into our findings.


We have had a British Gas service plan for quite a long time now.

They used to do what appeared to be a fairly comprehensive service, clean the jets, dismantle and examine various parts, etc. Now a service seems to be little more than check the flue and a coffee break. When I spoke to a service engineer, he told me that several engineers had been badly hurt and they weren’t allowed to do things like they used to – health and safety !!!

Our aging boiler breaks down about once a year or two and the repair engineers seem to be of a better standard so we now wait until it breaks down to get it serviced and they seem to do a much better job.

I would like British Gas to supply customers with a list of everything a service engineer should do when they service a boiler.


Over the years I have found gas engineers to be a rather opinionated lot whereas there should be a uniform and technical approach to the condition and rectification of a boiler in accordance with the manufacturer’s specification. They seem to have a habit of disagreeing with advice given, or criticising work done, by colleagues in their own company. My response has been to say that I will call the company and get an inspector or supervisor to check their work; a retraction usually follows. In another Conversation [“Are you happy with how your boiler is serviced?”] there was reference [19:08:15] to the service engineer not wishing to be watched while he serviced the boiler. That is just unacceptable.

I wonder whether the engineer who has contributed this Conversation would like to comment on the quality assurance systems in place and on-site inspection and test arrangements for checking the competence of field engineers. The engineers certify their own work and complete the safety and compliance documentation. In nearly forty years of having gas boilers serviced annually there has never been a follow-up inspection or check that the records submitted to the company by the engineer are correct. The likelihood is that the work is done satisfactorily since the number of serious incidents involving gas boilers is very low but that might have more to do with the safety protections and shut-down systems installed in the boilers than with the quality of servicing.

Alfa suggests that the service company [BG in his case] should supply the customer with a list of everything a service engineer should do when they service a boiler. I agree with that and was thinking they should go further and put a video on-line to show the correct procedure when I realised that might tempt some people to try and do it themselves which could be very dangerous.


Thanks to ‘Anonymous’ for posting this Conversation.

Which? has reported the findings to the Gas Safe Register. If every one of ten engineers has failed to carry out their work correctly then there must be something serious wrong. If boilers are left in a potentially dangerous condition, will any of the engineers be removed from the Gas Safe Register, either permanently or until training and assessment has been completed?

I appreciate that it is not within the remit of Which? to take direct action but we really need to be told what action the GSR has taken to deal with the problem. Presumably GSR will make a response if Which? does a press release but I want to see evidence of action, not the usual apologies that organisations make when publicly criticised.

I wonder if ‘Anonymous’ and other responsible engineers think should be done to tackle the problem, and in particular why so many engineers are not doing what they should. This is not the first time that Which? has highlighted problems with boiler servicing.


Hi Wavechange. Some more information for you for our online news story:

We’ve shared our findings with the Gas Safe Register. It promised to look into our findings further. A spokesman said: ‘Our experts inspect around 30,000 gas jobs every year, and if there are any instances where we find that an engineer is not working safely, we take appropriate action to remedy this.

‘Following Which?’s claims, we are looking into the registered businesses to inspect their gas work.’

We also shared our results with the firms we investigated. In statements, they all said safety was their priority and wanted to investigate further. Now we are calling for better checks on incompetent engineers.


Thanks Patrick. I appreciate it is not within the remit of Which? to take direct action and that problems are always reported promptly to the relevant organisations.

The response from GSR looks like a typical response from an organisation when Which? uncovers a problem as a result of undercover investigation or otherwise.

If GSR informs the public – either on its website or via Which? – of large numbers of engineers being struck off the register or retrained and reassessed then I might be prepared to believe that they are taking appropriate measures. There is no comment about the Which? investigation on the GSR website and I rather doubt that will will learn of any action unless Which? keeps up the pressure.


Patrick, I’m assuming all 10 servicing engineers you used were gas safe registered, although the report does not say so. Did you check that they did not have bogus credentials?
If you had an accredited expert to inspect the work done and “We also exposed engineers making potentially dangerous mistakes.” would it not have been appropriate to have taken legal action against the companies that provided them?
The usual “we will investigate” (you’ve already done that) and “we take appropriate action to remedy this.” (what action?) are usually just brush-offs and it all gets forgotten
Perhaps when serious problems arise Which? should bare its teeth and take direct action.



Thanks for these comments. We will definitely be following up our investigation with both the Gas Safe Register and the companies involved to see if our findings have made any difference and what action has been taken – or could be in the future. The companies we used all claimed to be Gas Safe registered and we have passed our findings on to Gas Safe to look at further.

Do watch this space for more on this subject in the months to come though – we certainly haven’t finished looking at this issue.


John Creasey says:
23 August 2015

Hi Ellie – personally, I think that this is an excellent starting point. Hopefully if ‘Which’ can keep the foot (albeit lightly maybe) on the pedal, standards can be pushed upwards.

I’m sure that most people can point out people in their own organisations who fall short of expectations, but when it comes to something like ‘gas safety’ it becomes more critical and important.

The report doesn’t state what type of boiler was serviced but does mention that it was tested by some with the cover off. There are occasions with the newer types of ‘High efficiency’ boilers that the main front cover is indeed off when carrying out certain tests and obtaining readings. Adjustments are then made to the gas valve with the front off. I am assuming that it was not one of these types of appliances, but I haven’t spotted it in your report.

I only mention this for clarity as I wouldn’t want a client to think I was doing something incorrect having read the Which report and not understood the difference between appliances.

All boilers should be serviced ‘according to the manufacturer’s instructions’, and this is the overriding criteria – I am sure that your expert would have been working on this basis.

Also similarly and quite worryingly, there is a gas engineer who has posted in the past that the PCB – printed circuit board should be taken out and inspected at servicing times. I know of not one single manufacturer who would want you to do this, and indeed any I have spoken to have been amazed at this suggestion. (as have other registered installers). Scary stuff !

Keep up the good work.