Anything automatic will fail sooner or later. If you are getting gas in your system, you have a problem which needs sorting. Air vents work the other way as well, and air can get in as well as out. Fix problem and use manual vents.
I don't have a problem; I shall be draining my CH system down this summer, replacing the zone valves etc. My air vents are the old type and I no longer have a key for the smaller square head. So I thought I might replace the air vents too. That's why I wondered if automatic vents might be the better choice.
Air collecting in rads continually is a sign of a problem thet needs sorting. With manual vents you are made aware that air is collecting with automatic ones you are not.
On a sealed system the pressure can also drop slowly as these valves let out air.
If you need to find a tradesperson to get your job done, please try our local search below,
or if you are doing it yourself you can find suppliers local to you.
Select the supplier or trade you require, enter your location to begin your search.
Please select a service and enter a location to continue...
Are you a trade or supplier? You can create your listing free at DIYnot Local