Another Pressure Loss

[kingjohn]

Last week I noticed air in the top radiator - about 10 inches from the top, so I released the vent valve and repressurised. At that time there had been a little reduction in the system's pressure. A couple of days ago the pressure guage on the Vailent 630 Eco Tec had dropped to zero, so I repressured the system.

Today it had dropped to zero again. I have now pumped up the pressure vessle (was 0.58 bar, now 1.4 bar) and repressurised the system. There is not a significant loss of water through the pressure relief valve.

Accepting that I will need to call in a plumber, what sort of problem does this suggest?

 

[terryplumb]

Is water coming out the pressure relief pipework or not ??
Does the pressure rise to around 3 bar when c/ heating has been running for an hour or more ?

 

[Gasguru]

You vessel pressure is double the pressure it needs to be (assuming you're in a normal house) and that will make the leakage appear to be far worse.
Any leak on the safety valve is significant.
Continual trapped air in a rad often indicates a pipework leak.

 

[kingjohn]

Is water coming out the pressure relief pipework or not ??
Does the pressure rise to around 3 bar when c/ heating has been running for an hour or more ?

Difficult to say as the pot also gets rain water at times. The level hasn't risen so I would say no. The pressure doesn't rise much in normal service. Having repressirised this morning the pressure has dropped to zero again, so I have called for the cavalry!

You vessel pressure is double the pressure it needs to be (assuming you're in a normal house) and that will make the leakage appear to be far worse.
Any leak on the safety valve is significant.
Continual trapped air in a rad often indicates a pipework leak.

Thanks, I've reduced the pressure. Yes, air has returned to the top radiator

 

[CBW]

Take pressure to approx 2.8 bar, and this may help show a leak on the pipework above/below that radiator with trapped air.

 

[kingjohn]

Defective Drayton valve. The soaked carpet hadn't reached in front of the sofa!

System now working but the filling loop will need replacing as the taps are dripping. Such is life!