Why does my boiler lose pressure when it’s cold outside?

Oftentimes, problems with boiler systems arise due to a loss of pressure. While this can occur due to natural wear and tear over time, there are other factors that can cause property boilers to lose pressure. For homeowners, it’s important to recognise when their boiler is losing pressure, why and how to resolve the issue. This is because it can lead to less efficient heating and increased costs. 

In this blog, we break down why boilers are more likely to lose pressure during periods of cold weather. 

Why boiler pressure is important

Boiler pressure is essential to the functionality and efficiency of modern boilers. This is because many internal boiler components carry some volume of water, which changes in line with variations in pressure. These boilers use an expansion vessel to compensate for the increased pressure that comes when the water is heated. When the system experiences low boiler pressure, it can result in no hot water for use in outlets or central heating. Even if all the components in your boiler are working perfectly, loss of boiler pressure can compromise the ability of the unit to provide heat. 

How to check boiler pressure 

Most boilers will be fitted with a pressure gauge that indicates the pressure levels within the unit. In modern boilers, the digital display will typically show an error code to indicate that there has been a loss of pressure. In both cases, you should check the boiler manual. For the former, this will tell you what level of pressure is considered too low or too high for that particular make/model. The typical range is between 0.7 bar and 2.5 bar. For boilers with a digital display, you will need to check that the error code on the screen corresponds with the error code for low pressure. 

What effect does cold have on boiler pressure? 

Cold weather can cause your boiler to lose pressure. When this happens, you can try and attempt to resolve the issue by topping up the pressure manually. It is often best to source a replacement part to guarantee the problem doesn’t keep reoccurring and leaving your home without heat. Below are the reasons cold can cause loss of boiler pressure: 

•  Frozen pipes – condensing boilers will have a number of pipes that feed water in and out of the unit. One of these is the condensate pipe. This part is more susceptible to freezing as it passes into the outside air, and so is more exposed to the elements. Freezing causes pipes to get blocked, preventing water from reaching the boiler for heating. 
• Boiler light goes out – as the boiler is used more often, it is more likely to develop an issue that results in the pilot light going out. This leads to a loss of heat and pressure. It can also be more difficult for the light to be reignited when the outside temperature is very cold. 
• Faulty parts – Many people also tend to experience boiler problems when it starts to get cold simply because the system parts are put under increased stress. This, coupled with long periods of inactivity during summer months, can lead to faults. We provide a rapid delivery service for key boiler parts and spares, such as pressure gauges, to ensure your home is heated properly when it’s needed most. 

Other factors that can cause a boiler to lose pressure 

Boilers can lose pressure at any time of the year, no matter what the outside temperature is. As such, you should check your boiler’s internal pressure regularly to ensure it is functioning properly. Other common causes include: 

Fast delivery of boiler spares and parts 

National Boiler Spares has an extensive range of new and refurbished boiler replacement parts. We possess the industry knowledge necessary to stock the key spares and parts you need to resolve issues that stem from low boiler pressure. These high-quality boiler spares can then be delivered direct to the address where they’re needed, often the following day. Contact us if you have any questions about boiler remanufacturing and repairs.