Air in heating system

[Burt Stormberger]

Hi all,

Hoping to get some advice...

My house is a 1980s build with the dreaded microbore. I've recently had an extension done and a fair bit of work done inside.

Where the heating system has been extended, 15mm has been used, but some of the original microbore still exists. All of the rads have been replaced for new ones and the system has been converted to a pressurised system from an open system with F+E tank in the loft.

Since the system has been refilled, there's been an issue with air in the system. This results in very noisy (whooshing) system through the pumps and causes the boiler to overtemp and short fire. The plumber has fitted a couple of automatic air vents and been over bleeding rads etc but there is still a problem.

He's now suggesting that this is an inherent problem with microbore in that it is harder to get the air out and he's basically saying that it will just have to work out over time. It's already been a few months since the work was done and we've been running the hot water system every day although the heating has only just been started up over the last few weeks.

Is this right?? Surely there must be something that can be done.

I'd be grateful to hear your thoughts...

Thanks

 

[twgas]

What boiler/system do you have?
Do you have to add water/pressure to system?
By "over bleeding" do you mean leaving bleed nipple open after the air stops and water comes out?

 

[Burt Stormberger]

Hi Mick,

Thanks for the reply.

Boiler is a British Gas 330. It was here when we bought the house. No idea when it was fitted but there is a sticker on the side that says it was serviced in 2010 so at least that old.

The system does hold pressure. The plumber told me to top it up if the pressure goes down as air gets out - but I've only had to do this a couple of times.

When I said 'over bleeding' I meant he'd been over to the house bleeding the rads. Sorry - my bad English! As far a I can tell, his technique for bleeding is as good as anyone else's!

Cheers

 

[RigidRaider]

It may not be air but hydrogen from oxidation inside the rads. Was inhibitor added when it was refilled?

 

[Burt Stormberger]

I'm pretty sure it was but I'll check.

It's been like this since it was refilled. Could the Hydrogen build up that quickly?

 

[RigidRaider]

Depending on how brave you're feeling, how about trying this:


https://www.youtube.com/watch?v=0GXDKxX9C7E

 

[Burt Stormberger]

Thanks for the idea. Looks exciting!

None of the rads need bleeding at the moment so I'll see if any gas builds up and give this a try.