Pressure relief valve and replacement?

[thenewb]

Hi there, appreciate the assistance in advance. We had a leak today in the hot water tank cupboard, which originated from a little device which I think is the pressure relief valve, see:

http://i.imgur.com/Np78lTs.jpg

http://i.imgur.com/c6jPpQA.jpg

http://i.imgur.com/2d4qV8G.jpg

Picture of where I unscrewed it from

http://i.imgur.com/pgYoBTq.jpg

http://i.imgur.com/uZ0FS6F.jpg

So, I guess it needs replacing, so I wanted to confirm a few things:

1) It's a pressure relief valve, is that correct?
2) If so, I've done some searching and I can't seem to find a similar one, what can I replace it with?
3) Is this a simple job i.e. safe to do without a qualified installer?

Thanks!

 

[just pumps]

Personally looking at that I`d want the whole system cleaned.

 

[thenewb]

Personally looking at that I`d want the whole system cleaned.

Thanks, would a plumber be able to do that? I might have to replace the (what I think is) the pressure relief valve in order to have water and schedule and appointment during normal hours.

 

[just pumps]

Sure clean it up and put it back keeping an eye on it then book the plumber and show them that photograph.

 

[thenewb]

Sure clean it up and put it back keeping an eye on it then book the plumber and show them that photograph.

I can't put it back, it's leaking at the top of that valve, so I'll need a replacement first

 

[thenewb]

OK, it appears that it's an anti vacuum valve, and there is no-one with stock that's open - are there any alternatives? I think actually from reading another thread that I shouldn't be working on it?

 

[just pumps]

If it is a sealed pressurised system then no you shouldn`t be working on it as being pressurised it is essentionally a bomb