Problem with air in system

[MikeAustin]

I'd give it a couple of drain/fill/run pump/drain cycles so you can feel confident it's all out.

In a fit of panic, I had already taken the afternoon off work to do just this. The system is draining as I type.

some chemical makers offer a neutralising chemical after using their cleaner.

I never saw him use anything like this.

Is yours an open system with a Feed & Expansion tank in the loft? If so, sponge it clean of any mud.

Yes, I am also emptying this, but sponging it out will be useful as well.

I am fairly certain that the 'air' in the system is actually hydrogen. I had no idea it could generate such volume. I really hope it has not eaten too much of the rads. Also, the drain that he used at the boiler is above it. I hope stainless steel is not too prone to acid![/b]

 

[MikeAustin]

After two lots of draining, filling and running the system, it now seems to be OK. I put Fernox in the last fill - and it is much quieter. After the previous fill, I had some bleeding to do - but nothing flammable coming out this time!

Once I have been running a few days, I will do a proper rad balance. One of my rads is quite cold. It is physically about 40 feet away from the boiler (and probably about 55 feet away in pipework). Another rad seems to collect more air than the rest (it always has done) but that makes it more manageable.

In summary, the problem with my system was just that it was choked up. This caused the boiler to short cycle. I called my installer in to check out the boiler, replace a cylinder, fit new rad valves and flush the system. He fitted the cylinder and valves and did a simple mains flush. For the boiler, he replaced £240 worth of components but it didn't help. He then flushed through with FX2 and everything moved fine. But he didn't flush it out properly leaving active acid producing hydrogen in the rads.