My boiler has recently began to increse in pressure up to 4 bar. My central heating works fine for about 30 mins and then gradually increases in pressure. Water is coming out of the discharge pipe and the pressure is flashing with a red lamp. The only work I have had done on it recently was to have a 2 port valve head replaced about 2 months ago, as it had failed.
Do I need to get somebody out or is there a way I can release some of the system pressure?