Boiler losing pressure

[Carlos_UK]

Hi, I decided to bleed my radiators today which dropped the system pressure from 1 bar to 0.5 bar, so I topped up back to just below 1.5 bar and then the pressure went back down to around 1 bar, so I topped up again only to find the same thing happen, so I went round each radiator and made sure the bleed valves were all tight (which they were) and topped up again, this time the pressure dropped to just above 1 bar, I put the heating on and the pressure rose and stabilised at 1.5 bar once hot.

Should I be concerned as normally when I have to top up, which is vary rarely, the pressure stabilises first time?

The boiler is an ideal classic ff230 in a 3 bedroomed house with 9 radiators.

Thanks,
Carlos.

 

[bewsh]

Have you checked the PRV discharge pipe isnt dripping?

 

[Carlos_UK]

Doesn't appear to be

 

[Carlos_UK]

Something else that has occurred to me is that if there was a leak, surely the pressure would drop whether its hot or cold?

 

[bewsh]

If there's a leak, sometimes if the radiators are hot, everything will expand and seal the leak until it cools down.

But, also, with the heating on and the expansion, the pressure will also increase - as you said, it goes up to 1.5bar when hot.