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Replacing Central Heating Pipes for A Combi Boiler

Are you thinking of getting a Combi boiler Installed to replace your old one? If you are, you would need to replace your old central heating pipes as well.

Combi boilers are trending in the UK due to their space-saving design. They provide central heating and water heating solutions in the same place, which makes them a must-have! Combi boilers are high-performance boilers and provide instant heating and hot water on demand. Doing so requires a high volume of gas in a shorter period of time.

Gas gets delivered through central heating pipes from the meter to the boiler and comes in various sizes. According to Gas Safe regulations, at least 22mm diameter gas pipes are necessary if you have a Combi boiler installed or hoping to install one.

Many homes in the UK use 15mm gas pipes to connect the meter to the conventional boilers. But as Combi boilers are becoming more and more of a hit, these pipes also need replacement with gas pipes of diameter 22mm or above.

All About Central Heating Pipes!

Central heating gas pipes are responsible for supplying gas from the meter to the gas-fired boiler. These gas pipes come in four different sizes (15mm, 22mm, 28mm and 35mm). Their usage depends upon the type of boiler, the distance between the meter and the boiler, and the boiler manufacturer.

The pipe diameter predicts the volume of the gas that would be able to make its way to the boiler. Old boilers have 15mm gas pipes installed with them as they require a lesser amount of gas. But with a Combi boiler, you need to have at least 22mm pipes that would provide a sufficient gas volume to support instant water heating and central heating.

Why are Larger Diameter Gas Pipes Required for Combi Boilers?

Combi boilers provide hot water quickly compared to regular or system boilers that gradually heat the water in a cylinder. Combination boilers need to burn a larger amount of gas in a shorter time, to meet the immediate heating and hot water requirements. That is why the gas pipes should be larger to supply enough gas volume to support a Combi boiler’s instant working.

Regular and system boilers slowly heat the water in a cylinder and so don’t require large amounts of gas in a shorter time. That is why you could use these boilers with gas pipes of 15mm diameter.

Gas Safe regulations state that at least 22mm diameter pipes should be used with Combi boilers for proper functioning. You could also use 28mm or 35mm pipes depending upon the unit’s power output requirements.

15mm or 22mm, What Should Be the Ideal Pipe Size for Combi Boilers?

Comparing Combi boilers, you might have noticed that this boiler uses a gas inlet pipe of 15mm. A smaller diameter pipe is only used where the gas pipe connects to the boiler itself. The rest of the central heating pipe coming from the meter would still be of 22mm diameter.

The 15mm gas inlet pipe would be connected to the 22mm gas supply pipe with a reducer by a Gas Safe registered engineer. Using a reducer would allow a safe connection between two pipe sizes without affecting the Combi boiler’s gas supply.

In case the gas supply pipe has to cover a long distance to make its way to the boiler and consists of bends, you might need 28mm or 35mm pipe. The Gas Safe certified engineer would be responsible for recommending the ideal pipe size for your central heating system depending upon your requirements.

Gas Pipe Sizes for Worcester Bosch

Greenstar is one of the most popular boilers of Worcester Bosch. All of the Greenstar boilers have a gas inlet of 22mm. Worcester Bosch has made it a must that the gas supply pipes should be at least 22mm in diameter under all circumstances.

Gas Pipe Sizes for Vaillant Boilers

Most Vaillant boilers come with a 15mm gas inlet pipe fitting, while some boilers like the ecoTEC Exclusive 843 Combi comes with a 20mm gas inlet pipe.

Replacing the Pipework

If you are replacing your old boiler with a new one chances are you would need to get your pipework replaced as well. The complexity of pipework replacement would depend upon the type of flooring in your home as it involves the lifting of floorboards.

If you have plenty of space under the floorboards, then the gas pipes will be easier to replace. In contrast, a house with stone and tile flooring would be much more difficult as it would require a lot of work uprooting it.

Cost of Pipework Replacement

Now you would be wondering about the cost of the pipework replacement. It would entirely depend on how complex the replacement work is.

You should consult a Gas Safe registered engineer to get an idea about the cost of gas pipe replacement in your home. To ensure that you are getting the best rates, we recommend you get quotes from multiple engineers. Comparing all these quotes and choosing the one that suits you best both price and expertise wise would help you feel confident that you are getting the real deal.

Summing It Up!

Gas pipes are responsible for delivering gas from the meter to the boiler. If you have an old boiler with 15mm diameter pipework and are planning to replace it with a Combi boiler, then you need to get the pipes replaced as well.

With a combination boiler, you would need at least 22mm diameter pipes depending upon your requirement.

The cost of replacing the gas pipes would depend upon the complexity of the replacement work. You should get the price quoted from a couple of engineers to get a fair idea about the cost of replacement and go with the one that suits you best.