Why does my boiler keep losing pressure

Why does my boiler keep losing pressure

An incredibly frustrating situation, one we see a lot sadly.  So why does my boiler keep losing pressure? We’re going to help you understand, what it is.  Why it happens.  Furthermore, how do we prevent this from happening again.

So, what causes it?

It could be many ways you could be losing pressure from your boiler/system.  The most obvious being a leak.  Now if you’re lucky, this leak is above floor level, easy to trace and can be fixed.  No need to read on.  Problem solved.  Your pressure will hopefully now stay stable.

Though in many cases we’re not always that lucky.  In order for a system to lose pressure, something needs to be removed from it.  Now this doesn’t always have to be water.  This can be air also releasing itself from the system.  This can be done via an automatic air vent.  Which its sole purpose is to remove air from a system or boiler.  Without letting out water (not always the case, but you get the idea behind one).  

Why would I have air in my system?

Well, not every system can be free from air.  This can be a very time-consuming job and with so many ups and downs in many systems.  It’s not always possible to get every single drop of air out of the system.  If your system is dropping in pressure having not long ago drain down.  You could just be victim of having air in the system due to this and after a few weeks this may settle down.  If it continues to become frequent, then you may have an issue.

Another way you could have air in the system or what could seem like air.  Is a gas buildup.  This is caused by magnetite in your system. (More on that another time).  Which can cause gassing in your system.  If you are frequently venting your radiators, have cold spots at the bottom.  This could be a sign of this buildup being present within your system.

One thing you do need to understand, if you are venting your radiators, you must replenish your system via your filling device.  As it’s been known, when customers complain about pressure drop.  It’s actually been them causing it by venting radiators.  And not realising the replenishment was needed.

Moreover, the only real way you can lose pressure is when either air or water is removed from it.

How to solve it?

Leak Sealer:  So there are no products on the market, such as Sentinel and Fernox.  Which allow you to administer Leak seal agent, which reacts and is meant to plug a potential small leak.  We have experienced mixed results.  The only time we really use this product is when we have exhausted all other options. This may not help your pressure problem

Trace and Repair the Leak:  sounds obvious right.  An ideal scenario is you find the leak and simply repair it.  

Has anyone checked your boiler? In some cases, the leaks aren’t always obvious.  The pipe outside. Has that been checked and is there water present cascading down your wall?  This is an indication that your boiler is losing pressure via the morning discharge pipe.  This can be caused by a vessel failure.  It can also be caused by the pressure relief valve not seating and subsequently letting by.  Or it could be both. But potentially it could well be that your boiler is at fault here.

We do not advise you do this, but a method that we use.  Is a visit first thing in the morning, where we isolate your boiler from the system.  We make sure the pressure is a steady 1.2 bar.  We make sure the mains power to the boiler is off.  We then return last call of the day to see what the pressure is done.  If the pressure is maintained and the moment we open the valves back up, we get a drop!  Then we know our focus needs to be on the system and not the boiler.

If you have pipework and solid floors, there are several ways you can look for the leak.  Though this is a very tricky undertaking.  Finding the reason for your pressure loss here, is a tough job.

A heat gun can be very useful which are expensive and would suggest a company to do this for you.

You can hire a gas company who would administer a gas into the system and have equipment that will trace this.

Replace sections of pipework and redirect pipework that’s under floor to more surface mounted.  As the lime, in cement can attack copper for unprotected pipework can cause corrosion, weakening the metal and causing lakes within the system.

How to prevent this from happening again?

If you are installing new pipework and are intending to bury this into concrete flooring.  Protect the pipework with Denzo tape or insulation.

Regular maintenance of your boiler is super important.  By checking the boiler annually, you are checking the vessel and its integrity along with the pressure relief valve.

Having a clean heating system for the kickoff and then an inhibited one will protect your heating system from any internal corrosion.  A magnetic filter is a must have gadget for your heating system.  These are installed with all new boilers.  If you don’t have one, get one.

Don’t leave any leaks, it will only get worse, see it sort it.  

When fencing radiators, make sure you are replenishing your heating system to 1.2 bar when cold.  Topping up your heating system when the system is hot.  This can lead to inaccurate pressures and once settled will show you a lower pressure within your system.  This could manifest as a leak when in fact it was under filled in the first place.

We hope you found some value to this blog.  We’ll be working on some videos soon to bring these dulcet words to life.

Thanks and have a great day

Tom