Air in radiators

[Traceybubble]

I had a new c/heating boiler fitted in September, my upstairs radiators keep filling with air, I've bled them about a dozen times, but every few days or so they fill up with air agian. I've bled them when the heating has been turned off. Do I need to call out an engineer, or is there something I do myself?

[stanleyman]

This shouldn't happen, probably a design fault in the system, you need to get the installer back, don't be fobbed off.

[buildersmate]

There are two possible reasons for this. The first is a design fault, the second is corrosion occurring.

Regarding the first, air may be getting into the system from a number of different places - the expansion tank if its not a pressurised system or even microleaks in the pipework. Just because no water is going out doesn't mean that air isn't getting in.

If there is no inhibitor in the CH water, corrosion can occur with the stell rads. The byproducts are black sludge and hydrogen gas. The gas collects in the top of a rad.

In both cases, get the installer back it shouldn't be doing this.

[grahamfreer]

if you are venting rads every few days then position of pump is wrong so get installer back to check. my guess is you have gone from an old gravity system to a fully pumped system & the plumbe has left cold feed & expansion as they were or pump is wrong way round