Most boilers need a pressure of about 1 to 1.5 bar when the heating is off. If it keeps dropping, there is usually a small leak or a problem with the pressure relief valve or expansion vessel.
What to check
- Check the gauge on the front of the boiler when the heating has been off for a while.
- Look for drips under radiators, around valves and below the boiler. Also check the small copper pipe on the outside wall, which is where the pressure relief valve drains.
- You can top the pressure back up using the filling loop. Your boiler manual shows how.
- If you have to top it up more than once a month, call me. Topping up keeps adding fresh water, which leads to sludge and corrosion over time.
Need it fixed?
I cover Northampton and nearby villages. See boiler repair for prices and what's involved.