What Pressure Should My Boiler Be?
Not sure what your boiler pressure should be? Don’t worry — you’re not alone. It’s one of the most common things homeowners ask us about. The good news? It’s usually a simple fix, and knowing what to look for can save you time, stress, and a cold house.
What’s the Right Pressure for My Boiler?
Most modern combi and system boilers are happy when the pressure is:
- When cold: Between 1.0 and 1.5 bar
- When heating is on: Up to around 2.0 bar
A bit of movement is totally normal. It’ll go up when the heating’s on, then settle as things cool down.
Where Do I Find the Pressure Gauge?
You’ll usually see the pressure gauge on the front of the boiler, or just underneath it. Some are dials with a needle (analogue), others are digital displays. Most have a green ‘safe zone’ to help you spot if it’s in the right range.
What If My Boiler Pressure Is Too Low?
If the needle drops below 1.0 — especially under 0.5 — your boiler might shut itself down to avoid damage.
Signs of low pressure:
- No heating or hot water
- Error codes like E118 or F75 on the display
What to do: You can usually fix low pressure by slowly topping it up with the filling loop. Aim for 1.2–1.5 bar. Then restart the boiler if needed. If you’re not confident, just give us a call — we’re happy to walk you through it or come take a look.
What If the Pressure’s Too High?
On the flip side, if the pressure’s creeping above 2.5 or even hitting 3.0 bar, your boiler could start releasing water through the overflow pipe — or shut down altogether.
Possible causes:
- Overfilling the boiler
- A faulty pressure relief valve
- A problem with the expansion vessel
Quick fix: Bleed a radiator to release a bit of pressure. Still too high? It’s time to book a boiler repair with a qualified engineer.
How Often Should I Check the Pressure?
Ideally, give it a quick glance:
- Once a month
- Any time you bleed the radiators
- If your heating or hot water isn’t working properly
If you’re needing to top up the pressure regularly, that’s a sign something isn’t quite right — and it’s best to get it checked.
Can I Adjust It Myself?
Yes — within limits. Topping up the pressure is safe if you follow the instructions in your boiler manual. But if the pressure keeps dropping (or rising too high), it’s not something to ignore. You might have a hidden leak or a faulty part — and too much DIY fiddling can cause more harm than good or void your warranty.
Need a Hand With Boiler Pressure?
We help homeowners across Dunfermline, Kirkcaldy and Fife with pressure problems every week — whether it’s a one-off fix or part of a regular boiler service.
We’ll find the cause, explain what’s going on in plain English, and get everything back to normal quickly — whether that’s a simple top-up or a more involved repair. If your system’s on its last legs, we can also help you explore boiler installation options with fixed pricing and honest advice.
📞 Call us: 01383 660098
🌐 Learn more: Boiler Repairs in Dunfermline
We’ll take the pressure off — literally.
