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Brief cases: proving a boiler is not fit for purpose

After repeated problems with a relatively new boiler, Derrick contacted Which? Legal in desperation. But was it possible to prove that the British Gas-recommended boiler was not fit for purpose?

Just a few years after buying a British Gas-recommended boiler, Which? Legal member Derrick Bradfield was told it was unsafe to use because of insufficient gas pressure.

Derrick Bradfield

Derrick Bradfield

That was just one of a series of problems with the boiler he’d bought for £2,595 in January 2009. British Gas had recommended it based on an engineer’s assessment of what his house needed. But the engineer never tested the house’s gas supply pressure. The major problems with the boiler began as early as February 2012.

Derrick had taken out a service contract for the boiler with Npower and asked it to investigate. When it found the boiler unsafe to use due to the insufficient pressure, Derrick had to pay to replace parts not covered under his service agreement.

In October 2014, British Gas agreed to replace the entire gas supply pipe through the house to the boiler. This resolved the problem at first, but two months later the boiler failed again. This meant that Derrick was left without heating or hot water over Christmas.

The repeated failures caused such inconvenience that he had the boiler replaced by another company. He informed British Gas and said that he wanted it to pay the cost. However, it refused to accept liability – so Derrick came to us for help.

Our legal advice

Our lawyers advised that British Gas breached its contract under the Supply of Goods and Services Act 1982. This is because it failed to use reasonable care and skill when installing the boiler, which may have not been the right size for the house and so not fit for purpose.

For contracts entered into on or after 1 October 2015, these rights are under the Consumer Rights Act 2015.

What the law says

Where goods or services are bought on credit, depending on the type of agreement, a credit provider may be jointly liable for a breach of contract by a trader. A consumer may be able to bring an action under section 75 of the Consumer Credit Act 1974 to recover their financial loss from the credit provider.

As the boiler was paid for with a loan from the company GE Money, Derrick was able to pursue it for his financial loss and in March 2015, it agreed to write off the £1,600 balance of the loan.


From what I have read, it is questionable whether it was the boiler or the installation that was unsatisfactory, but it should not have happened. I had not realised that a boiler could be unsafe because of low gas pressure due to restriction in flow caused by a gas pipe that is too small.

Back in the 1970s I discovered that the heating engineers that fitted a gas boiler for my parents had ignored instructions and fitted the wrong diameter gas supply pipe (too small) despite a clear label inside the boiler. It never caused a problem and a service engineer said it was not a problem, but it’s worrying when instructions are ignored. I wonder how common these problems are.


Looking at the installation instructions for my boiler the first step is to check the main supply to the meter to ensure it is capable of carrying the required gas flow to all connected appliances. It then requires the connecting pipe to the boiler to be at least 22mm for 19kW and 25kW, possibly reduced to 15mm for smaller output boilers providing the required working pressure and flow rates can be achieved. However, this will depend upon the length and routing of the pipework – 3 to 4m from the meter is suggested for these sizes.

Pressure required for natural gas is given as 18.5 mbar for NG at the boiler test point. This must be verified at commissioning, and checking it is also a requirement at the annual service.

So some questions arise. If the original installers did not check the gas pressure (which is in breach of contract I’d suggest and may well breach the requirements of BS 6891 that covers the pipework installation). This surely would be all that is needed to bring legal action against the installer.

However, the boiler should have been serviced every year (for safety, and probably necessary for insurance) when the pressure is required to be tested. Why was it then “a few years” before it was declared “unsafe”? Had the mains supply pressure dropped? How had it performed until then?

And why did “spare parts” solve the problem of an inadequate supply pressure?

It all seems a bit confused so perhaps Which? could be more specific about just where the problem lay.


I agree with Malcolm 100%. As I was reading the article I was composing something very similar (but far less eloquent) in my head.

It would seem here that BG as a consultant has acted competently, and the installer (who incidentally may also be BG) has failed to identify the additional work necessary to get decent gas flow at the appliance.

Incidentally, whilst I have no time whatever for payday loan issuers at their rates per day that exceed what sensible borrows pay per annum, I actually feel sorry for those who lend money somehow ending up jointly and severally liable for problems not of their – **or their clients’** making. I believe this law was brought in to catch retailers/clients who went bust or who were crooks, not to help pin misdemeanours on them that were not the fault of their clients.


We had a new condensing boiler fitted to our previous property. I was concerned about the fact that it was not possible to view the burner flame due to the absence of a window in the boiler casing. I have since learned that the absence of a window is widespread in new boilers. In my opinion this is a definite retrograde development as it prevents the householder from doing a simple visual check on the state of combustion: flames with a nice blue cone indicate complete combustion but flames which are yellow like a candle indicate incomplete combustion with production of carbon monoxide. Boiler burners behave just like the Bunsen burner at school. So on this basis I conclude that modern condensing boilers are less safe than their immediate predecessors as they need an specialist instrument (a gas analyser) to detect the state of combustion rather than the human eye. Boiler manufactures wake up and stop cutting corners! Which? may like to consider this matter.


Good Mn Dave,,,,,,,,Long before we had gas analysers we had flame colour……..on old gas cookers the colour of the flame was everything

As to windows Dave,,,,,,,,,,,,,not a chance………..do you know that people dont know about flames to day……….


DeeKay, “do you know that people don’t know about flames today” It is never too late to learn- even about flames and this includes little old ladies sitting in front of an open gas fire on a cold winter’s day-it could mean the difference between life and death!


dave, quite agree. Some people will know about flames so I see no harm whatsoever in providing a viewing window if it is easy to include. But not essential.

Many statements are made to the effect that “no-one knows” or “most people will agree” , probably made without thinking. I’m sure I’ve ( well, may have) been guilty of over egging (well, maybe just ever so slightly) a point of view on occasions (well, possibly, maybe one…..or perhaps two).

I am one of those who believes a significant number of people can manage the basic calculations needed to navigate their way through life. Just because some people cannot is not a reason to unnecessarily dumb everything down to a meaningless level.

In this case I would like Which? to clarify exactly what happened in the history of Derrick’s boiler. There are unanswered questions.


I absolutely agree, Dave. It is very difficult to imagine why any company should produce a boiler with a viewing window that can provide visual reassurance that all is well. Boilers are often serviced only once a year and a fault could go unnoticed for months or until the heat exchanger is blocked with soot.

I can think of quite a few examples of products that are not as safe as they could be, for example plastic-cased kettles, fan heaters and other household products with a powerful heater in a plastic casing.