Does your boiler appear to be on its way out? Is your boiler losing pressure? or just running at low pressure? Are you beginning to fret about the potential expense of a new boiler? Perhaps you are here to start the research process before making that dreaded call to a plumber to get a quotation. This guide aims to help educate our readers on the different types of boilers available and the importance of choosing the right type of boiler for your situation. 

Essentially there are three main types of boilers on the marketplace today in the United Kingdom – Combi Boilers, Regular Boilers, also known as heat-only and system boilers.

Each type of boiler has its benefits and factors that could influence your decision, including the pressure of your water mains and the age of the rest of your system. Another factor, while not directly related to the operation of your system, is the size restraints of where you want the boiler to be located. 

Let’s start by discussing the different types of boilers in greater depth. 

Combi Boiler 

A combi boiler performs two primary tasks: it powers the central heating system and heats your hot water. A combi boiler is a single unit and is typically hung on a wall. They are far and away the most popular type of boiler in use in the United Kingdom today and the most likely type of boiler used for boiler replacement. 

The main benefit of a Combi Boiler is instant hot water, which is generated by the use of a metallic heat exchanger. This eliminates the need for a hot water storage tank, is more efficient to run as only the water you need is heated, and it also puts an end to the hot water running out when the entire household needs a bath or shower.

Combi boilers are powered by gas or oil. Compared to traditional boilers, Combi Boilers also tend to have a smaller footprint, meaning they can be installed in a more confined space in addition to the space-saving benefits of not needing to have a water tank. 

As with everything in life, there are a few compromises that need to be taken into consideration. Typically because the water is being heated instantly, water flow rates will drop slightly if two or more showers or baths are being used simultaneously.

What Pressure Should Your Boiler Be

This means that if you live in a mansion with lots of bathrooms then a combi boiler may not be the most suitable choice. However, for the vast majority of families, with the exception of a wedding or other significant family event where everyone is trying to get ready at once, a combi boiler is a perfect choice. 

Heat Only (Regular Boilers) 

Depending on your age, before the invention of the Combi Boiler, this was the standard type of heating system installed throughout the United Kingdom. Regular boiler systems consist of three main components – the boiler, the cylinder and the tank.

Regular boilers supply hot water directly into the central heating system. They also have a storage facility (the cylinder) for on-demand use. Coldwater is stored in a tank that was traditionally stored in the loft. Thanks to the benefits of gravity, that water is then fed into the boiler, where it is heated and then used instantly or stored in the cylinder. 

Regular Boilers do not suffer as much in regards to flow rate, which means they are the preferred solution for homes with many bathrooms or where there is excessive demand for hot water at certain times of the time. If your heating system is slightly older and you are trying to avoid replacing the entire system, then a heat-only boiler might be a better solution as it does not demand such a high-pressure system.

Older systems are more prone to problems when a high pressure closed system is installed. Finally, if your mains water supply is notorious for having low water pressure, then a heat-only boiler might be a good choice as both Combi, and system boilers require adequate water pressure to work at full capacity and to maximise efficiency. 

On the negative side, a traditional boiler will require extra space for the boiler itself and the water tank. Some modern heating systems may not be compatible with this type of boiler, and another issue is that there is only limited storage capacity for pre-heated water.

This means the last person into the shower in the morning may run out of hot water. Perhaps the biggest worry is if the water tank leaks. As it is stored in the loft, the potential for damage to your home is quite significant. 

System Boilers 

System boilers could be considered an upgraded version of a regular boiler. They are able to deliver hot water on demand as well as heated water to supply your radiators. Another considerable advantage compared to a regular boiler is that they do not require a cold-water cistern tank. 

The key benefits are very similar to that of a regular boiler. They are ideally suited to busy homes with a high requirement for hot water in a condensed period of time. Thanks to being fed their water directly from the water mains, they do not need as much space as a traditional boiler, as there is no need for a water storage tank. In addition, because there is no water tank, there is no concern regarding leaking or indeed freezing of that water tank in the winter. 

Because there is no water storage tank, a system boiler relies on the water mains pressure to function efficiently. If you know from personal experience that you live in an area where the mains water supply is low, this might rule out the option of a system boiler. As with a combi boiler, a system boiler requires high pressure to function, so if the rest of your system is old, a system boiler may not be suitable.

Finally, if you are considering switching from a combi boiler, remember you will need to factor in the need for a hot water storage cylinder, which requires additional space. 

Don’t Rush Into A New Boiler: Could You Simply Be Suffering From a Leak. 

Hopefully, this article has helped you gain a basic understanding of the different types of boilers, but it may be the case that you do not even need a new boiler. Have you checked if your heating system is airlocked?

If you are suffering a consistent drop in boiler pressure, then contact ADI Leak Detection today on 0800 731 3843, and hopefully save yourself the cost, hassle and inconvenience of a new boiler.