Repeated air/hydrogen forming in closed heating system?

[Fatboyslick]

Would love some advice please:

I had 4 radiators replaced in September as part of a kitchen refit. This included new copper piperwork behind the walls where the Rads are placed. The system wasn’t flushed or anything, just installed and the plumber left.

A few weeks later we noticed that our two uppermost radiators (not new ones) weren’t heating fully.

We spoke to a Gas Engineer who assessed the boiler - which was fine - and said that as we have a Closed Heating System we either have:

a) hydrogen forming from the flux because the plumber who fitted them didn’t flush the system it add inhibitors or

b) we have a leak somewhere.

We have no visible signs for leaks so what he did was add System Cleaner and left it a week with us having the heating on a lot to circulate it.
He came back, ran a simple flush and added in a Miracle Seal & Corrosion Inhibitor.

However now, 3 weeks later, the same two radiators are not fully heating up again.

The boiler pressure, which I’ve been monitoring every other day, remains the same. Worth noting that I did hear “bubbles” passing through other radiators recently. And we also had a new air vent “thing” installed to replace a faulty one (see photo) - could that be sucking in air???

It’s an ideal logic boiler that manages both hot water and central heating with an unvented megaflo water tank

Any ideas???

 

[Chuck]

Fresh copper in a heating system will evolve hydrogen at a gradually reducing rate for, typically, about six months. This is a side effect of the 'passivating layer' forming.

I'd just bleed the affected radiator(s) and top up to restore the system pressure if necessary. Expect to need to do this several times at lengthening intervals for about six months.

A correctly place automatic air vent can avoid the need to bleed radiator(s) manually but you may still need to top up with water a couple of times to replace the water that has been converted to hydrogen and copper oxide by the above process.