Seal System Loss

[Brucey]

How much should you expect to loose pressure in a sealed system over time (forsay 6 months)

Cheers

 

[TBServices]

Nothing, once it's settled down.

 

[bewsh]

In an ideal world, you'll lose nothing. But you will get very little water loss from micro leaks on radiator valves, etc... But if you only have to top it up once every 6 months, thats not bad really

 

[Best]

I have sealed systems that will stay near enough to their full initial pressure for many years. I know some were doing at least 6 years without barely dropping fractionally.
All pipework in copper, with well soldered joints & any brass connections & valves sealed perfect & decent radiator valves & no auto vents fitted. Slight corrosion on valve heads (including TRVs) or on brass joints, is slight leaks & means you are adding water to the system to top up pressure, which isn't good for corrosion.
Some boilers seem to have weeps on their factory joints which doesn't help.