Leak in loft - advice please

[JonHeath]

Hi all,

I moved into a 1938 house about 8 weeks ago. The house suffered a burst pipe in the loft 2 days before we moved in which was fixed.

We have been doing work in the dining room which involved taking a radiator off and draining the system down. This was a few days ago.

This morning we woke to water dripping through the sealing in one of the bedrooms. Upon investigation in the loft the leak was coming out what I presume is an air valve. I've attached a picture below.

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• JonHeath
• 27 Jan 2011
• 1

Water was coming out the black cap thing on top which was loose. I screwed it back into place and the leak has since stopped.

I suspect the plumber might have losened this when fixing the original problem months ago, and the draining of the system has forced it off.

I'm now concerned that this could happen again, although the cap seemed to screw nicely back on. Any advice on whether I should be looking to replace this valve with something more modern?

Thanks
Jon

 

[Stamina]

just fit a new one......simples

 

[hi1]

Having first drained the system- not so simples, if its not leaking now i'd leave it alone.

 

[JonHeath]

I'm tempted to leave it unless otherwise advised, as the screw cap (the black bit in the picture) seems to stay firm fine now I've screwed it back on all the way. I'm just worried it has worked its own way off with pressure and that it'll happen again.

 

[kirkgas]

it is a spring loaded auto air release, when new you loosen the black cap to open the air path in the event of the system pressure building up the spring allows the excess pressure to vent off, when the pressure lowers the spring closes, however in practice when it vents out dirty water and air some debris gets stuck in the spring leading to water through the ceiling, closing the cap will not allow it to vent off, this isnt daangerous but as the cylinder is high any air will trap there decreasing hot water temp at the taps, which means you will need to go up the loft and crack the fitting open to release the air, dont know whether air will ever trap in there again but it is likely, best option would be to part drain the heating (3-4 mins) to reduce water pressure at that height and fit a new manual air release (the same as is in the end of most rads) there are various fittings available for this either as i said the rad air plug or a 15mm air release point which requires a flat screwdriver to open it, technically an auto air release is best but could lead to what you have now

 

[Axel]

They are £ 7 to buy and take 5 min to replace.

 

[Agile]

Idealy they should be left about 1/2 turn loose.

When they have been disturbed they can drip for a few days.

It does not matter if you choose to close it but in that case open it in a week and see if its still dripping.

Its not very important to replace it.

Tony