You should have a manual to the boiler to explain.
ARE YOU SURE ITS LOW? In the red usually means the pressure is too high. Its obviously a gauge with no markings, so is the needle to the left or the right and is the red to the left or the right?
If its too high do not do the following. Instead let it cool down, the pressure will gradually decrease. Unfortunately I fear it will just do the same again, pressure increase to an unsafe condition and shut off boiler, are there any error codes on the display?
To re-pressurize will be something like this:
First locate the filling tap, be a tap immediately underneath the boiler, do not confuse this with any of the main pipes that connect to the boiler i.e. mains water in, hot water out, radiator flow out, radiator flow in, gas inlet.
Next, this may or may not need to be done whilst the boiler is powered on, but not with heating on so be sure to turn off the heating switch/timer etc.. and preferably whilst noone is using the hot water taps.
Turn (anticlockwise) the filling loop tap slowly and you should hear the system re-pressurize and the pressure gauge will gradually move up.
DO NOT OVER PRESSURISE. 1.0 bar or roughly half way if its a gauge. The exact pressure will be found in the manual.
Ensure you close (turn off) the tap when the correct pressure is reached.
Now attempt to turn on the heating, should fire up with no problems.
Robert, October 2010
