Are you worried you may need to upgrade your gas pipe before fitting a combi boiler?

Perhaps you’ve already been advised that your pipework needs upgraded by a Gas Safe registered heating engineer.

Having worked with many customers who have needed this exact upgrade before having their combis fitted, I know it can add a bit of extra stress for any homeowner.

Below, I’m going to tell you why you may need to upgrade your gas pipe, and what the work might involve.

Why do you need a pipe upgrade?

Current Gas Safe regulations state that a 22mm supply pipe must be fitted from the combi boiler to the meter. It may also have to be upgraded to 28mm and 35mm in sections if the gas line is a particularly long distance, has many bends and turns in the route it takes or services many appliances.

A lot of old, non-combi boilers were fitted with a 15mm gas supply pipe as this was all they needed to heat the water via the hot water cylinder slowly over an hour or so.

A combi boiler is a little different, as it heats the water instantly, meaning it burns a lot of gas for a short period. Because of this, it requires a larger pipe to provide the correct gas pressure (for the correct amount of fuel).

TIP: You may also require an upgrade if you are installing a larger output boiler than at present for a higher hot water output. This may require the gas (fuel) pipe to be upgraded.

Is a pipe upgrade always necessary?

The short answer is: no.

A pipe upgrade may not always be necessary, but it will depend on your current pipe set-up.

Sometimes, the existing pipe is already 22mm from the meter to the boiler, so will not need to be upgraded.

However, there are other considerations to take into account.

For instance, you may have a meter which has an old lead connection joining to copper. The engineer can’t leave this in place, so it must be upgraded.

I have also come across situations where the pipe is 22mm but not demonstrating adequate pressure at the boiler, due to carbon deposits within the pipe. Therefore, visually the piped looked okay, but was not adequate for the job.

Which pipes are affected?

When an engineer fits a boiler, fire or cooker, he must carry out a soundness test at the meter. Any visual lead pipe must be upgraded.

Appliances must be gas-rated to ensure they can operate at their highest output with the correct pressure. If this pressure cannot be achieved, then the pipe needs upgraded.

WARNING: If you install a combi boiler where the gas pipe is not the required specification, you will be contravening Gas Safe regulations and the manufacturer’s instructions, breaking the law.

How much will it cost?

The cost of upgrading your pipes will really depend on your current set-up and circumstances, which is why you should always ask for a home visit and a fixed price quote from your chosen engineer.

As a rule of thumb, the more complex the job is, the more expensive it becomes. For instance, if you live in a bungalow with space under the floor, it’s likely a very straight forward job.

However, if your property has stone or tiled, polished floors, it can become a complex and costly job which may involve lifting floorboards, and avoiding certain areas.

Because of the above, upgrading your pipework could cost you anywhere between £150 to £800.

Your next steps

If you are concerned about whether or not you need to upgrade your gas pipes before fitting a combi boiler, call your local Gas Safe Registered engineer to give you an assessment (or quote if necessary). If you suspect any gas appliance or pipework is unsafe call the Gas Safe Register and have one of their inspectors visit your property to assess your pipework, appliances or workmanship.

Remember, there is usually a valid reason for requiring a pipework upgrade, and it is very unlikely your chosen engineer is trying to charge you for unnecessary work.

Gas pipes cannot be concealed in concrete floors or walls, and your engineer cannot connect to defective or substandard pipework. They must either cut and isolate, or replace the pipe entirely.

Conclusion

If you’re unsure of having to upgrade your gas pipe before fitting a combi boiler, this blog should help set your mind at ease. According to Gas Safe regulations, a 22mm supply pipe must be fitted from the combi boiler to the meter. So, if you have an old 15mm pipe, it must be replaced.

Old lead pipes must also be replaced, along with any pipe that is not demonstrating adequate pressure to the boiler due to carbon deposits in the pipe. An engineer can check this by conducting a working pressure test on each gas appliance.

If you are unsure of whether you actually need to upgrade your gas pipes, contact your local Gas Safe Registered engineer to carry out an assessment (and quote if necessary).

If you think any of your gas pipe work is unsafe contact the Gas Safe register who can send someone round to inspect the pipe work in your property.