How to reduce your boiler pressure

1. Switch off your boiler and wait for the heating system to cool.
2. Identify and check the boiler pressure gauge.
3. If it’s above 2 bars, you’ll need to reduce the pressure.
4. Ensure the filling loop or relief valve is tightly closed.

If the boiler pressure is too high, there’s an increased chance of leaks developing in the system. But if boiler pressure is too low, the system won’t work as well. So keeping the correct boiler pressure is important to make sure that your system heats your home efficiently.

What Boiler Pressure Is “Too High”? Anything above 1.8 bar isn’t ideal. 2.3 bar starts to become more serious and when most boilers hit 3 bar, they’re in the red zone on the pressure gauge. So, the unit is likely to lock out and display a fault code.

How to Adjust Your Water Pressure Regulator

1. Turn Off the Water. Locate the water main and slowly turn the valve to the off position.
2. Adjust the Pressure. The regulator will have a screw or bolt and a locking nut system.
3. Re-test the System.
4. Secure the Lock Nut.
5. Turn the Water Back On.

While historically, boilers would over-pressurise and explode with alarming regularity, modern boilers are manufactured to be able to withstand excessive pressure, and can typically handle an operating pressure of 20 PSI. When pressures increase beyond this level, the boiler can fail, which can lead to an explosion.

High pressure is rarely the reason for a boiler explosion, but various other reasons such as faulty internal parts can cause it.

Combi boiler pressure increases when the heating is on as your boiler uses fuel (gas, oil etc) to heat the water – this increase in pressure is natural. If your boiler is behaving as it should, the pressure will stabilise again once the system is switched off and cooled down.

Boiler pressure is controlled by the expansion vessel, the balance of air versus water in your central heating system. Too little air in your expansion vessel and the pressure may become too high. This is why it’s important that the installer work out the cause of your boiler’s high pressure.

Your area’s water needs may have changed, causing the increase in pressure. Your water pressure regulator may be broken. Sometimes air can get trapped in the pipes, temporarily increasing your water pressure. To relieve the pressure, run your taps for a few minutes to allow the air to escape.

Signs Your Water Heater Is Going to Explode

1. Leaking Temperature and Pressure Relief Valve. The T&P valve regulates temperature and pressure inside the hot water heater tank.
2. Always Open T&P Valve.
3. Popping Noises.
4. Brown Water.
5. Rotten Egg Odor.

A damaged or failing Low Water Cutoff or LWCO control or valve a damaged or clogged LWCO can cause over-filling of the steam boiler if it is not properly-sensing the boiler water-level.

High boiler pressure isn’t dangerous, even if it’s showing as three bar on the pressure gauge. In most cases, the boiler will turn itself off if the pressure goes about a certain level and a working PRV should successfully control the pressure, preventing it from getting too high.

System leaks are the most common cause of boilers losing pressure and one of the most vulnerable areas is joints on your piping or boiler connections. These are generally soldered and the combination of pressure and hot water will wear away at these over time. Leaks are extremely common.

Attach the radiator key into the square section in the centre of the radiator valve

The first and most obvious problem that leads to high boiler pressure, is a heating system that has been overfilled. By topping up water via the external filling loop, you can add pressure to your boiler. Your boiler needs sufficient water in it to operate correctly.