Ariston Clas HE 30 - Cannot pressurize system past 0.5 bars?

[verachion]

Hi, long time lurker but untill now I have not had any problems, that said, I have just drained my Ariston Clas HE 30 heating system down to put in a new radiator in my lounge once I was finished I refilled the system only to find that I had put the TRV on the wrong side, so I drained the system down again and refitted the TRV on the correct side and I am now trying to re fill the system but the pressure is stuck at 0.5 bars and will not go beyond this? If I leave the water tap open a white box to the left of my boiler whirrs and seems to pump out the water? The white box is called a Boss condesate pump? I have never seen one of these before?

My question is what can I do to refill the system and why is it not allowing me to pressurize the system to 1 bar? there are no leaks and the pressure is not moving at all.

 

[ServiceNumpty]

Could be your pressure gauge is stuck at 1/2bar, as you repressurize the prv opens and discharges into the condensate pump. Have you tried tapping the gauge.

 

[verachion]

Could be your pressure gauge is stuck at 1/2bar, as you repressurize the prv opens and discharges into the condensate pump. Have you tried tapping the gauge.

Thanks for answering me, do you mean tapping the pressure gauge where the numbers are?

Edit: Just tried doing that but it didn't work. It sounds as though it is refilling but after a 10 seconds or so the pump kicks in again.