Boiler losing pressure, problem radiator?

[MsCrow]

Hello

We have a (hated) Baxi 105HE boiler. We replaced the expansion vessel a year ago. I noticed yesterday it was losing pressure overnight to 0 making the boiler noisy. I topped it up to 1. This is a new problem as I keep an eye on the pressure gauge after the expansion problems. During operation it's ok. For hot water the pressure temporarily drops by a couple of increments, for radiators, the pressure increases by 0.5 a bar and then returns to a cold state when off.

I have looked about the house and all the radiators are ok....except for the one in the cellar which has a corroded bottom. There is a sign of a recent drip-drip leak. I have turned the radiator to its frost setting. Obviously, we need to replace it asap.

Would this be enough to bring the boiler pressure down over 24 hours? Or, is it also likely a boiler problem?

Thanks

 

[twgas]

isolate the leaking rad completely, once done, I would suspect the pressure will stay good.
turning one end down will not help, the lockshield needs turning off as well.

 

[MsCrow]

Thanks

I hoped so and got a friend (plumber) to shut off the cellar radiator. The boiler will be serviced on Monday just to double check but since yesterday there has been minimal pressure loss. I'd far rather face the prospect of replacing a radiator.