Bottle air vents

[GMM]

Today I noticed that I had a leak from the bottle vent in the hot water circuit. Looked up a new one on Sfx (

). Very poor reviews but options are pretty limited on a Sunday so it was that or let it drip for a week. Fitted it above a service valve (being mindful of the reviews) and sure enough, when I let some pressure into it, it weeps a small leak from the thumbscrew on top. The leak stops when I screw the thumbscrew all teh way down but, presumably, this means it can't vent any air (/gas) that accumulates there. Presumably this means it's a duff one, which sort of vindicates my service valve but what's the best thing to do: a) get a decent one or b) use some other approach. My system has a tendency to produce gas (burns off at a radiator bleed valve) which no amount of inhibitor seems to stop and my friendly gas safe man is a bit mystified by, so an automatic system to bleed the circuit would be preferable, but what alternative could I use if not a bottle vent?

Any thoughts chaps?

[harry]

air-vent-15mm/34359).  Very poor

Dunno what you mean by a "bottle vent" If you mean an "automatic air vent" it has a float inside that opens to let any air present out. Probably just got a bit of shit on the valve seat. Dismantle and clean up, likely it will be OK.

If you are having hydrogen gas production this needs to be checked out. Not all inhibitor are the same. There are special (expensive) ones for systems with aluminium components (boiler).

You may have a sacrificial anode somewhere that has corroded away (as they are meant to). Usually in the boiler. This would need replacing if it is the case.

As the sacrificial anode corrodes, gas is produced but you need to be sure the gas is coming from the anode and not your boiler

[harry]

e-air-vent-15mm/34359).  Very poor

Galvanic_anode

More on sacrificial anodes.