what should boiler pressure be when heating is off

The optimal pressure for a boiler when the heating is off should generally be between 1 and 1.5 bars. The needle of the pressure gauge should remain above the lower limit set by the boiler manufacturer at all times. Most boilers will highlight this area on the pressure gauge in green to help you see if the needle is pointing to the correct amount of pressure. Some boilers will also have the critical zones below 1 and above 2.5 marked in red to help you identify any issues. It is important to check your boiler manual to make sure your boiler is operating at the optimal working pressure recommended by the manufacturer.