Automatic air vents - central heating...

Adrian · 2008-09-27T12:40:24+00:00

HI AllI've not used float-type auto air vents before - so I may be doing something wrong - expert advice welcomed !Regular readers may recall the saga of my heatpump system - which was causing the CH header tank to regularly overflow. This was finally sorted by bleeding trapped air out of the heat store.Systems looks like a conventional CH boiler - except that the 'boiler' is a heatpump, and the return from radiator and DHW circuits passes through a 200 litre, heavily insulated copper 'heat-store' before it goes back to the heatpump. When the heat pump switches off the system circulates water from the store through the DHW / CH until it's cooled sufficiently.Anyway....The whole thing's piped up in copper / pex - the circulating pump has a little brass float-type auto air vent on the highest point of the circuit - but the feed to the top of the heat store had no such vent.The only way to bleed the air from the heat store was to slacken off the compression fitting at the top of the store and wait while the air finds its way out - necessitates leaning over the store and applying lateral pressure to the pex pipe to slightly unseat the pipe - a slow and uncomfortable process!So - I bought another auto air vent and fitted it as close as possible to the feed into the heat store - confidently expecting it to vent air .. automatically ....Trouble is - it doesn't It's still necessary to do the 'lean over the heat store for a hour at a time to let the air out'....So - what don;t I understand about using these auto air vents ?It's fitted pretty much at the high point of the circuit - certainly on a level with the union into the heat store. Fitted into a 3/4" x 3/4" x female threaded 'tee' - with the air valve fitted vertical and into the threaded part of the tee...Any ideas please ??TIAAdrian

Sep 27, 2008 21 Replies

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Spamlet 17 years ago

Actually, I've just been recalling the black plastic floats in the Ducati carbs, and, in fact, the tickler plunger actually just bopped the top of the float, cos I've just got a mental picture of the little dent it made thanks to the float being bashed against it all the time by the road bumps...

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Dave Plowman (News) 17 years ago

That's how they all worked on every bike I've owned. Which isn't that many, though. And the last one about 40 years ago.

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