Air vent in hot press for central heating

Lex Luthor

A few weeks ago, I discovered a leak in my hot press on the auto air vent in the heating system. Bought a replacement and fitted it.

Only trouble is, how do you set them up?

The one that was in previous, the little knurled nut at the top was slightly open, so I am presuming it vented any trapped air automatically.

The new one, if you even have it open the slightest bit, the water just trickles out of it and doesn't stop. So what I am having to do, is close it off completely, and every week or 2, open it slightly and bleed off the exceess trapped air until water comes out as you would if bleeding a rad.

I want to try and get away from doing this as I never had to do it before. Did I buy the correct item? It says on the invoice that its an auto air vent and it cost me about €4.

Any advice?

rooferPete

Hi Lex,

Sounds like you bought a bottle vent, personally I'm not a fan of them, you can buy what looks like a blank cap with a vent similar to a rad vent in the middle.

As for venting the pipe all the time it shouldn't really be needed, there are a lot of systems installed that have neither type of vent and they work fine.

That said a newer system may have a need for one maybe Pipers can give you the full info.

.

JamesM

The automatic air vent you showed a few weeks ago should have the knurled nut loose - open. That's how it works - bleeds automatically. Not sure what is happening now.
Jim.

rooferPete

Hi James M,

Would the system being in constant "Top up" mode be putting more pressure on the vent than it was designed for ?

.

Lex Luthor

James M, the one I bought recently looks identical to the one I replaced only physically smaller.

The one removed had the knurled nut loose alright and seemed to work away automatically. The new one, if opened at all, just leaks....maybe its a dud.

This new one can't be left open at all or it just starts to leak.

pipers

bring it back and replace. If you want to get a good quality one go to BSS on the south circular road.

Lex Luthor

pipers wrote:

bring it back and replace. If you want to get a good quality one go to BSS on the south circular road.

you think its faulty then....?

I couldn't be bothered bitchin to them about a €4 part....I'll try swing by BSS during the week.

What does a good quality one cost?

JamesM

rooferPete wrote:

Hi James M,

Would the system being in constant "Top up" mode be putting more pressure on the vent than it was designed for ?

.

Pete, Honestly don't know.
Lex, is the pressure very high in the system ? Is it connected to the mains, or the storage tank in the attic.
The vents do leak sometimes after some years, but not from new. Pipers could well be right and it is faulty.
As Pete says you could use a rad vent instead. There shouldn't be a build up of air in that location anyway, if the system has plenty of water.
Jim.

Lex Luthor

The pressure reading of the system down at the boiler is about 1 bar.

I keep the top up valve closed for the heating system in the hot press and top it up every now and again.

Maybe the part I got was just a dud out of the box.

Will replace and follow-up

kiss103

As far as i'm aware these work by a floating ball rising on a water level , if you get diirt deposited on this ball , then they can leak / drip, i've found to shift this just get a pin and push this ball down to create a temporary better leak and it should flush the dirt off the ball , worked for me on several of these units over the years , but as Pete says there not a great solution !

pipers

Its not a floating ball, its a piece of Balsa timber.
Meddle with these at your peril