Sealed system grabbing air

[Matt0029]

Any ideas why a sealed system with a combi could be grabbing air. The upstairs rads have air in and the system reads 3 bar cold. When the air is bleed out the system returns to 1 bar or less. It's an ideal instinct boiler basically a logic.

 

[ShaunCorbs]

You sure it’s not hydrogen ?

 

[Chuck]

Active corrosion. Has there been any recent work on the system, new radiators / pipework, etc.? Check the pH and inhibitor level in the CH water.

 

[Matt0029]

You sure it’s not hydrogen ?

How would I test this?

 

[Matt0029]

The system is around 6 years old new build all in copper. I'm pretty sure it had inhibitor put in it.

 

[Matt0029]

Active corrosion. Has there been any recent work on the system, new radiators / pipework, etc.? Check the pH and inhibitor level in the CH water.

If was active corrosion, it would be hydrogen?

 

[EvilDrPorkChop]

Sure it isn't blowing off and letting water out the system?

 

[Matt0029]

Sure it isn't blowing off and letting water out the system?

It's not no

 

[simonharper1971]

How would I test this?

id go for galvanic corrosion . It was common years ago to test for hydrogen gassing by holding a lighter against a venting radiator bleed nipple and see if you get a small flame. Make sure the curtains aren't anywhere near

 

[Matt0029]

I could bleed and test with a lighter? I wondered if you'd be anything to do with the expansion vessel. It's happened to quiet a few houses on this new build estate as said around 6 years all