Worcester 28cdi pressurised even aftrer draining

[flippet]

Recently had cause to drain the system for decorating purposes, which I've done a few times before without problem. However when I refilled the system, even though I stopped filling long before the pressure gauge reached 1 bar and bled the air from the radiators, the pressure kept rising (slowly) until it was over 2 bars.

I should note that on previous occasions there has been a delayed pressure rise, which is why I stop filling at about 0.5 bars anyway and wait for things to settle, draining off extra if necessary. This time, however, I have drained and bled the whole system and the gauge still reads about 2.

Is it likely to be a faulty gauge or is there some kind of localised pressure build-up?

BTW. I'm not planning on filling it again/testing it until somebody qualified looks at it (unless there's an obvious, easy solution), I'd just like to understand a little more first.

 

[pallen5000]

The pipe connecting the pressure gauge may be starting to get blocked.

 

[diverdee]

daft question but you havnt closed the valves on the flow and return pipe have you ?

 

[flippet]

daft question but you havnt closed the valves on the flow and return pipe have you ?

No, haven't played with anything other than the filling loop at the boiler - though interestingly I have located a dripping coming from the topmost pipe connected to the water-to-water heat exchanger.

I had assumed it was just residual water from when the filling loop was used, but it has kept on dripping and the pressure has dropped a little (about 0.2 bars) from what it was at this morning... does this indicate it may not just be the gauge?