Boiler pressure keeps going up and up!
Have you noticed that when your central heating is on the pressure on your boiler keeps rising? This is an issue that our Birmingham heating engineers attend on a daily basis and can be a relatively easy repair. In fact it’s an issue that should be prevented by getting the boiler serviced regularly by an expert heating engineer that does the job properly. Not a five minute service like some company’s offer.
So what’s causing the pressure to rise when the central heating is on. There are a few reasons that can cause this issue but for us the biggest issue is deflated expansion vessels. The expansion vessel can either be located inside your boiler or sometimes external, depending on the system you have. The job of the expansion vessel is to absorb the water expansion when the water is heated. It uses a diaphragm and compressed air to absorb this expansion. When the vessel has deflated which can happen over a year or longer the vessel fills with water. This means it can no longer absorb the pressure rise when the water is heated. So as the water is heated the pressure rises, you may have noticed on the pressure gauge that when the central heating is on the pressure gauge is going above 3 bar.
ITS GONNA BLOW!!!!
Regularly we hear customers say we’re worried the boiler will blow up.. but don’t worry there’s a safety device inside the boiler that protects the boiler from the rising pressure. This valve is called the PRV pressure relief valve. These valves are designed to discharge at 3 bar. And this might explain another issue you might be having. Is your pressure dropping all the time into the red and you have to top it up? Yep thought so.. so when your boiler pressure has risen high, it’s very likely the prv has opened and has been discharging the water to outside. You can usually see this on the outside of the property by where your boiler is fitted. You Will likely have a copper pipe that’s dripping water or leaving a water stain on the wall outside.
IS IT A BIG JOB TO REPAIR.
As mentioned above this repair is quite rare if the boiler has been serviced properly and the reason for this is, every year when the boilers serviced the expansion vessel should be drained and recharged and sometimes the shrader valve replaced. When this is done it’s very unlikely to become flat and cause this issue. But if your are getting problems with the expansion vessel and the PRV it’s likely you will need to replace the prv and service the vessel or occasionally replace the vessel or add an additional one if the vessel you have is to small for the system. Your heating engineer will be able to don this job and it’s fairly painless.
