Wondering why your boiler pressure keeps dropping daily? Discover the most common causes and easy fixes to keep your heating system running smoothly.
Pressure dropping in life is a sign things are going well, but in a boiler? Cold showers and icy radiators, and in the bleak midwinter, no one wants that.
Boilers naturally lose pressure over time, but if it’s happening every day, you’re going to want to know how to fix this.
Thankfully, we’re a team of expert boiler engineers with the know-how and experience to get your boiler back to its best. We’ve created this guide to give you everything you need to know about why your boiler pressure is dropping on the daily, DIY checks you can perform, and when it’s time to call a professional.
Key takeaways:
Boiler pressure is the balance of water and air within your boiler
Low pressure means your boiler can’t funnel hot water to your radiators or showers
Boilers lose pressure over time, this isn’t an issue
A boiler regularly losing pressure, however, could be a sign of a bigger problem
Leaks in your heating system, leaks in your boiler, and faulty parts can cause low pressure
There’ll be a chance that after reading this article, you come to the realisation that your boiler’s best days are behind it and it’s time to get a new boiler. We can help, Heatable supplies and fit new boilers next day.
Why Is My Boiler Dropping Pressure Every Day?
A boiler dropping pressure every day means something isn’t working the way it should. Low pressure equals no heating, leading to an angry household denied hot showers. You want boiler pressure that’s just right (and not too high either).
Let’s take a look at some of the most common causes behind a boiler losing pressure each day.
Leaks
Having a leak somewhere in your heating system is a guarantee that your boiler will lose pressure, because as it tries to funnel hot water around your home, a portion of that is leaking out.
In turn, the pressure will drop because the boiler is effectively pushing against the tide.
Unfortunately identifying a leak can be pretty difficult, because it could be coming from any one of the numerous pipes travelling around your home. Try as best you can to trace the pipes throughout the building to find any obvious signs of leakage.
Our advice is to check the joints and bends in your pipes in particular, because these are the parts of the pipes most likely to weaken over time.
After a while, water can escape the joints and bends, leading to pressure loss (and paradoxically increasing the pressure on you to find a fix).
Prefer video? Check out our YouTube video below on common causes of low boiler pressure
Air in the System
If air is trapped in the system, it can cause your boiler to drop pressure. Air accumulating in your heating system creates pockets of space that stop water flowing as it should, leading to lower pressure. It can cause too much boiler pressure too, which is why it’s so important to bleed your radiators every now and then.
Faulty Parts
Sometimes it might just be that a part in your boiler is faulty, which unless you’re a seer in all things boiler, is going to be really hard to fix yourself. Also, we really recommend against trying to fix a faulty part without boiler expertise.
Boilers are complex machines juggling highly flammable gas (or another fuel type) to keep you warm after all, and tampering with them can be dangerous.
Best to leave boiler repairs to the experts say?
Damaged Expansion Vessel
All boilers use something called an expansion vessel, which basically keeps your boiler safe as it heats water. It compensates for any expansion that happens when water is heated, so without an expansion vessel, your boiler would damage itself when it tried to keep you warm.
The picture above shows a standard expansion vessel
A damaged expansion vessel can cause low boiler pressure when water flows in to replace the air (usually when the rubber on the unit tears).
Here are some quick help guides:
How Do I Know My Boiler Is Losing Pressure?
The obvious sign is no hot water or heating, but you can turn to your boiler for confirmation too. Most modern boilers have a handy digital display that’ll show you what’s occurring within, and if your boiler has lost pressure, it’ll let you know.
When your boiler isn’t on, it should be between 1 and 1.5 bar (bar is a unit used to measure pressure). If it’s lower than this, it’ll either show you what bar it’s at, or will display an error code (look out for the E1 error code, a common code used for low pressure, or F22 if your boiler is from Vaillant).
The exact pressure will vary from boiler to boiler, but roughly speaking it’ll fall between the above range.
Related: What should your boiler pressure be when heating is on?
DIY Fixes for Boiler Pressure Falling Every Day
When it comes to low boiler pressure, you can usually top it up yourself and get back to a warm, toasty home. It gets a bit more complicated when the pressure is dropping every day, but we’ll run through the process of topping it up yourself just in case.
Step 1 – Find your filling loop
This is the pipe that connects a central heating system (your boiler) to the main water supply. You can find it directly underneath your boiler and you’ll use this to top up the boiler pressure when it drops too low.
Step 2 – Locate the taps
On your filling loop are two taps, which control the flow of water into your boiler. They’re usually pretty easy to identify (typically either black or red, but can be different).
Step 3 – Increase the pressure
All you need to do to increase pressure is turn one or two of the taps on the filling loop until they lock at 45 degrees. Let the water flow back into your boiler and keep an eye on the pressure gauge – once it’s reached 1 bar, you’re good to turn the taps back to their starting position!
Voilà, your boiler should be working again.
When Should I Call a Professional?
If, after increasing the pressure via the filling loop, your boiler loses pressure quickly again, then it’s time to bite the bullet and call in the professionals.
A boiler that’s losing pressure so soon after being repressurised is a boiler in need of some TLC. And we’re the team to turn to, having heaps of experience in repairing boilers and getting them singing again.
Repairing a boiler will cost £300-£500 on average, so you’ll need to have a think about whether this is worth it. If it’s a particularly old boiler, you might want to think about replacing it.
Should I Replace My Boiler?
No boiler lasts forever, and as they say, it’s better to have boiled and lost than to have never boiled at all (we’re pretty sure that's what Alfred Tennyson said anyway). So eventually, your boiler will heat your home for the last time and then you’ll need a new one.
It’s little use constantly repairing a boiler too, as over time, these repairs will become increasingly costly and could even end up costing you more than what a new boiler would.
To help you work out if it’s time to get a new boiler, we’ve written a handy guide on the 10 signs you need to replace your boiler.
Get a free, no-obligation boiler quote today
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