The pressure on my Vokera Compact bolier fluctuates from being either too high or too low. In most cases it is too high so I take out water from my radiators until correct level is reached, then for some reason the pressure works it's way up to being too high again. Why is this? I have taken the water from the radiators whilst the heating is both off and on.

Brenda, January 2008

Big A has given you the three reasons for pressure rises in boilers, nice one!

Justin, January 2008

Is your expansion vessel charged correctly?, Is the filling loop disconnected (if passing this will constantly allow water to enter the system, gradually building-up pressure)? If disconnected then there may be water passing thro' heat exchanger, you could try turning off the cold water inlet valve.

Big A, January 2008