/ Home & Energy

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.

James Davis says:
27 August 2015

As an experienced Gas installer, servicing and breakdown engineer I find it unacceptable that the level of servicing has not been met by the companies investigated by Which?

I feel it gives other companies and service engineers a bad name along with programmes like Rouge Traders.

I work for a company called “South Coast Boiler Services Ltd” and we actually do a lot of work for Corgi Homeplan who came out top in the investigation. We are also a Which? Approved traders.

I would like to point out that although the investigation proves otherwise, there are genuine traders out there that provide a good service.

It does also depend on the individual engineer and their experience. I know engineers that have been Gas Safe registered for over 30 years that have mainly carried out installation work so are not as familiar with servicing and breakdown work and therefore may miss the faults highlighted in the report.

They would have covered the basics in their training but in my opinion I would not want a Gas Safe engineer without at least 6 years experience in servicing and breakdown work servicing my boiler.

The current course takes 4 years if done via an apprenticeship but what a lot of consumers don’t realise is that not all Gas Safe engineers have completed an apprenticeship and that fast track courses are available.

A fast track course takes a matter of weeks. After that time you will be Gas Safe registered and can legally carry out Gas work. I cannot believe that these courses are available. I think it is dangerous to say the least that someone can enter a customers home with little or no practical experience and carry out Gas work. The government needs to put a stop to this but I’d imagine nothing will happen until someone gets blow up as the government are happy for the extra revenue for now.

I would be interested to know how many of the engineers completed a full apprenticeship.


It would be useful if the Gas Safe register of installers and repair/servicing operatives, showing details of their training and experience, and their qualifications with dates, were publicly available. As you say, someone who has spent most of their time doing gas plumbing and connexions to gas cookers might be out of date on modern boilers and unfamiliar with manufacturers’ latest models. It looks to me as though there is a need for a two-stage registration process [or three stages if an apprenticeship is included as I think it should be]. I should be surprised if a 12-week training course provides sufficient experience but it can nevertheless result in registration that means the operative can work on gas boilers, apparently without any requirement for supervision, or probationary period, or subsequent inspection. I believe it also means they can certify that the work they have done is compliant.

It seems there is a national shortage of registered gas workers running into the tens of thousands [depending on which estimate you believe]. Training providers compete to offer the quickest and lowest-cost route to registration. I question whether this approach is conducive to a proper safety system.

Jonathan M says:
31 August 2015

I wanted to write to you regarding a potential Safety flaw of New boilers. They are generally regarded as very safe, perhaps too safe, by some Engineers:

The thing is at the top of a boiler are two tubes with caps on. One is a safety valve for pressure overload and the other which is called the analyser test point is for the engineer to use to measure the composition of the waste gases and hence the boiler efficiency. So once you take the cap off the analyser test point tube and operate the boiler it will start leaking waste gases such as carbon monoxide, now that is ok if the engineer is measuring the gases but what about if he forgets to replace the cap?

Couldn’t happen? Think again:

My mother’s boiler is situated in an alcove and quite high up and the test point analyser tube is not visible from the ground.

My mother, 85, had the misfortune of inhaling poisonous fumes from a new boiler from when it was fitted in October 2010 to when I suspected it was leaking in Nov 2013, that is for 3 years. I called out the gas emergency who confirmed it was leaking gas from the top when in operation and I called my mother’s insurance the next day who sent an engineer who found that the analyser test point cap was off.

When I called the engineer who had serviced our boiler those 3 times, the most recent a month ago, to complain to him, his main concern was why we hadn’t called him first. Also in his defence he claimed that he didn’t use the analyser test point to check the gas, eventually he apologised and offered us £100 compensation.

Now my mother had been having terrible headaches, loss of appetite/nausea and fatigue for a long time and we had seen specialists who couldn’t find anything and when we thought about it these symptoms stretched back to about the time of the boiler installation. A colleague of his had installed the boiler because he was too busy.

So The boiler was leaking for 3 years because the original Installer, had forgot to replace the analyser test point cap. And the other engineer who by his own admission did not use this point to measure the waste gases, did not notice that the cap was off each time he serviced the boiler.

Also we did not suspect the boiler for my mother’s symptoms because we believed the engineer that “New boilers have positive pressure and can’t leak” and he also said we did not need a CO detector.

Fortunately, my mother has now made a full recovery. We complained to Gas Safe first and then checkatrade. Gas Safe decided they didnt need to visit as the fault had already been fixed I dont know what Gas Safe did but they didnt ask for proof of my Mother’s conditions and the engineers were obviously still in business as they rubbished my complaints later on on checkatrade.

Anyway if any good could come out of my mother’s experience, so that this could not happen to anyone else and it would also protect the Engineer, at the end of an Installation or Service a photo should be taken of the analyser test point tube and signed by the engineer and the customer. I already suggested this to Gas Safe.

And an improvement to boiler design would be for the analyser test point tube to have a valve so that even if you leave the cap off it wont leak. I guess I should be campaigning about this on social media, when I master how to use it.

I think leaving the cap off is something that is so incredibly negligent it should never happen, a bit like a surgeon cutting off the wrong leg, but it did happen to my mum and the engineers’ responsible were Gas Safe registered and had glowing references on Checkatrade. So I think everyone should know about this potential dangerous weakness of new boilers.

I was speaking to a Gas engineer sent to service my boiler and I told him about what happened to my mother and he said her life was saved by 4 factors 1) the boiler is so efficient that the waste gases would be at a very low concentration 2) that the kitchen door was always open and 3) that the kitchen’s sash windows were not air tight and 4) there was a window right by the boiler that we couldn’t shut properly.

Furthermore there is a bitter irony about this because my mother is a German Jewish Refugee and managed to escape Hitler’s Gas Chambers only to be nearly Gassed to death in her own home!


That is a worrying story. Many boilers are installed in high positions and in other places where it is not possible to see whether the test point tube safety cap is in place. Have the manufacturers and the HSE been informed of this problem that depends for safety on the installer and subsequent service engineers remembering to replace the safety cap? Given the fallibility of the human memory this is an unacceptable design flaw. There must be a way of providing a fail safe closure of the tube, or at the very least an audible warning signal [like a whistle] to indicate that the tube remains open. A mechanical or electrical interlock to prevent ignition would be better. This reinforces the need to have a carbon monoxide warning alarm positioned in the same area as a gas boiler. Modern houses can be almost airtight and often have very little ventilation when people close windows and doors on leaving the property.


Is this a problem only with new boilers? When my 19 year old free standing boiler was installed I noticed a smell of gas on each ignition. I have had this checked by various engineers who assured me this was normal and not dangerous. I do have a carbon monoxide detector in situ next to the boiler but have often wondered whether these detect gas leakage as well as carbon monoxide which cannot be smelt anyway. If only the latter then there is a need for a device to detect gas leakage also, particularly in elderly peoples homes since Jonathans 85 year old mum`s ability to smell would be somewhat diminished as part of the ageing process.

A few years ago I recall a very faint smell of gas when walking past a house where an elderly person lived and very foolishly failed initially to report it. It was during a visit from my son and daughter-in-law when walking past this house my daughter-in-law noticed the same smell of gas. I reported it next day and engineers came out immediately to investigate where they identified a gas leak coming from a vent on the footpath. The elderly lady had not smelt the gas when entering and exiting her house, which illustrates the necessity of a gas detector device in all homes where elderly people live.


If interested, more info re the effects of ageing on smell and taste can be found @ ageingcare.com – Problems with Sense of Smell in the Elderly.


It is a Building Regulations requirement that smoke alarms are fitted in all new properties and those let out but there is no requirement to fit a carbon monoxide alarm where a gas boiler is installed and gas detector alarms are never mentioned [the assumption being that our noses will alert us – as Beryl says, an unreliable presumption]. I have never seen gas alarms on sale alongside Smoke and CO alarms. I have never heard of the fire brigade assisting with the fitting of gas detectors.

In a house closed for several days a small build-up of gas can easily lead to a dreadful fire – it can be activated by the simple switching-on of the light as the tiny spark from the electrical contact ignites the gas [some light switches are worse for this than others]. Luckily it doesn’t happen very often but every year there are cases of houses being destroyed by gas explosions. The media never seem to follow up these stories after the immediate sensational reporting and tell us what the investigators found out about the cause. It might emerge if there is a fatality and the inquest is reported. Vulnerable people living on their own are at greater risk since they are more likely to keep all their doors and windows closed for warmth and have a tendency to cover air-bricks and other openings. They might also have old gas fires and cookers that are prone to a flame blow-out due to a sudden draught that then leaves gas escaping.


If confirmation is needed re diminishing sense of smell in the elderly more can be found @ ageingcare.com – Problems with Sense of Smell in the Elderly. It apparently starts at age 60!
Are gas engineers aware of this when training and told to be extra vigilant when servicing elderly peoples boilers?