Leak - Is this a pressure relief valve?

[G00NeR79]

Hi
Moved in to our new house last year and regularly going around repairing everything as you do. We have an Ideal Logic Plus HE30 and it loses pressure on occasion and end up topping it up once a month or so. Last night I noticed a leak, is this a pressure relief valve?

Luckily I spotted it before it's done any damage or staining to the living room ceiling below. The black plastic cap on top is where water is slowly dripping from. I tightened it fully and it did stop, but wasn't sure if this should be fully tight or is that a stupid question? Doesn't look in great condition anyways...

Not too sure on the whole system to be honest, think it's changed a lot over the years before we moved in as it went from a 2 bed to 4 bed double extension a good 15 years ago. Will add a couple more pics to get any more info on the setup

Any help is greatly appreciated

 

[jeff the gasman]

It's an automatic air vent and turning the black cap off won't hurt.
No rush to get a replacement.

 

[Whitespirit66]

No, it's an automatic air vent. Will need to drain down to below the AAV, unscrew it's compression fitting at the bottom and screw in a new one.

http://www.screwfix.com/p/bottle-air-vent-15mm/34359

 

[G00NeR79]

The only information left by previous owners was on how to top up boiler pressure - Fully open valve no.1, then open valve no.2 for a second and close. Least they number the valves for us

 

[Whitespirit66]

The black cap is supposed to be loosened to let the air that has been vented by the valve escape. You've done the right thing by tightening it to stop leaks. Obviously, when new valve fitted, bake sure the cap is loosened.

 

[stardanny]

An easy job, should take 10 mins to change. It a sealed system.

Disconnect filling loop at supply side and hang it in bucket, open isovalve on heating side to release pressure, till water stop running ( wouldn't be much water ), change AAV and put back loop to supply pipe and repressure it.

Daniel.

 

[G00NeR79]

Cheers for quick response, very helpful

Wasn't sure if it was a relief valve as only seen the type that are further down the pipework near the support for the shower pump.
So it's ok to fully tighten the screw cap until I can get out and get a new one. Like I say I did fully tighten it yesterday, but it was still seeping, so gonna have to change it.
Out of curiosity, why is it seeping water if it's meant to release trapped air?

 

[stardanny]

Dirty water, seal failed.

Daniel.

 

[Whitespirit66]

Includes a cameo appearence by George the cat.

 

[Whitespirit66]

duplicate

 

[Dan Robinson]

Will need to drain down to below the AAV,

You big jessie.


And I hate that annoying whatsit on YouTube...

 

[Whitespirit66]

Will need to drain down to below the AAV,

You big jessie.

Not me. I do 'em live.

And 3 ports.

 

[Richardthe3rd]

Will need to drain down to below the AAV,

You big jessie.


And I hate that annoying whatsit on YouTube...

Hold tight!! Poor Jaz @ Plumberpants he's taking a right doing from everyone & he's only trying to become a media luvvie like Roger what's his face.
Here, I've not seen Roger on the telly for some time is he 'resting'??!!

Is it just me or does that cylinder cupboard look a right Pik.y's Breakfast??!!

 

[Dan Robinson]

Is that his name? Flaming Nora! It wouldn't be so bad I'd he didn't get so much of the really simple things wrong.

Think Roger got rumbled for not being Gas registered.

He was nationally less annoying though.

 

[G00NeR79]

Is it just me or does that cylinder cupboard look a right Pik.y's Breakfast??!!

Lol, yeah I just love the slat shelving. Gives it a real classy look. I'll sort it out when I get round to it but as it's not used for storage or anything it's not high in my priorities list

So what would be the best/safest way to change the AAV - isolate water, drain hot water cylinder to below AAV level and swap over?