Vokera Linea 726 boiler losing pressure when central heating is switched off

[PJR0511]

Hi, I'm new here and this is my first post. We have a Vokera Linea 726 boiler which is, as best I can remember, about 10 years old. When the central heating is not on, the hot water is fine and the pressure remains around 1.5 bar, which I think is about what it should be. However, when we switch on the central heating, the pressure quickly goes up to about 3 bar and stays there as long as the heating is on. If we switch off the central heating, the pressure steadily drops to zero over a period of about one hour, and we then have to repressurise to get hot water. Can anyone suggest what the problem might be and how much it might cost to fix? I know very little about central heating, so if someone could explain at a 'boilers for dummies' level, this would be much appreciated! Thanks in advance.

 

[Dotty]

You'd be best just getting someone in to take a look. The component that has failed could possibly be repaired in which case it'll be cheap as chips, or it may need replacing in which case it's not. Geographic location makes a difference too to the price

It really needs eyes on.

Whereabouts are you, one of us may be nearby and available to help.

 

[PJR0511]

You'd be best just getting someone in to take a look. The component that has failed could possibly be repaired in which case it'll be cheap as chips, or it may need replacing in which case it's not. Geographic location makes a difference too to the price

It really needs eyes on.

Whereabouts are you, one of us may be nearby and available to help.

Thanks, we are in Milton of Campsie, which is about 10 miles north of Glasgow. The nearest major town is Kirkintilloch, about 2 miles away.