Alpha CB25 pressure rise problem

[powerlside]

Hello everyone,

I have a problem with our Alpha CB25 boiler.
Problem is little bit complicated to me.
We have had a problem with hot water this summer. I changed two parts like heat exchanger and I refurberd divert valve.
We always have problem with low pressure I have to fill it up the system every fortnite. We do not have leak our heating system I already checked all radiators.

Today I woke up and the main pressure raised to 3 bar. We used only central heating at night. I thought the problem could be water refill circuit but I closed the main water tap and the pressure went up over 1.5 bar but its stopped. When I open the main water tap pressure rising up immediately.
Can you give me any advice where is the problem? Which parts can be changed?

Ohh.. Yes I forgot, I've changed the PCB as well because the ventilator control has gone my old board.

Thanks fo any advice

 

[SimonG]

Yes get a gas safe registered engineer in and stop fiddling with a combustion appliance.