Homeowners are potentially being put at risk when getting their boiler serviced due to "shocking" work from engineers, a consumer site has claimed.
In a damning investigation, Which? called out 10 separate engineers to carry out a service, including from major firms such as British Gas, SSE and Corgi Homeplan.
It found that only two - British Gas and Corgi - bothered to carry out the minimum legal checks, while none at all followed the manufacturer's servicing instructions properly.
Which? executive director Richard Lloyd said more needed to be done to protect consumers.
"These results are shocking, with most engineers we put to the test failing to do what is legally required," he said.
"Faulty boilers could have serious or even fatal consequences for consumers so more must be done to check up on and crack down on incompetent engineers."
As part of the investigation, Which? set the boiler's gas pressure dangerously high, something six of the engineers failed to do anything about.
Other potentially dangerous failings included not checking the boiler case for leaks, letting unburned gas hiss out into the room and in two instances lying about safety checks.
Which? said it had shared its findings with the Gas Safe Register, which is responsible for checking gas work is done safely.
An SSE spokesman said: "Safety is SSE's number one priority. We do not tolerate poor safety or poor service and we take this incident extremely seriously. Engineers must abide by all gas safety regulations and SSE has very strict rules that engineers must follow. Any evidence of an employee breaking these rules would result in disciplinary action and we asked that footage be shared with us so we could investigate this further.
"We have reviewed our company practices, re-briefed all our boiler engineers and reiterated our mandatory safety procedures. If any customer has concerns about any aspect of SSE's service they should contact us immediately."
A British Gas spokesman said: "At British Gas, safety is our number one priority. We are known for having one of the best safety records in the industry, with an Ofsted judgment of 'outstanding' for our apprenticeship training schemes.
"We understand Which? have passed the detail of their investigation to the Gas Safe Register so we look forward to liaising with them to discuss this."
Of the 10 engineers Which? called out, five were from big name firms and five were independents chosen at random. Here is how they fared, according to Which?:
- British Gas and Corgi HomePlan
Did the legal checks but did not follow the manufacturer's instructions properly. Both engineers fired the boiler with the case off which, while not unlawful, our experts said could be dangerous without a proper risk assessment. British Gas fulfilled its customer pledges and filled out the paperwork properly. The Corgi engineer did not fill out the paperwork correctly (Corgi does not have any extra customer pledges to fulfil).
- Home Energy Services
Engineer took the boiler case off for just 13 seconds, failed to do all the legal checks, did not follow the manufacturer's instructions properly and delivered on only one of its five customer pledges. The engineer failed to do promised checks on all main boiler parts or look for gas leaks, and lied about his work on the written report. He also let unburnt gas hiss out into the room - a clear hazard.
Engineer did not check the operating pressure of the boiler - which, left as it was, could have led to a soot build-up and the production of carbon monoxide. The engineer failed to carry out all the legal checks, did not follow the manufacturer's instructions and failed on three of HomeServe's 13 customer promises - including not repairing any gas leaks, since he did not check for them.
Engineer did not take the case off the boiler, failed to do all the checks required by law and did not follow the manufacturer's instructions properly.
- Five independent firms
All failed the legal checks and did not follow the manufacturer's instructions - including one that did not take off the case or controls cover at all. None picked up on the dangerously high operating pressure on our boiler.
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