Help identifying brass fitting in flow from boiler

[cliffa]

Hi, I'm going to replace my CH pump. Whilst doing that I wondered what this fitting in the flow pipe from boiler was and what it is for and whether it would be worth replacing whilst the system is drained, it looks to have some seepage.

Many Thanks

 

[45yearsagasman]

Hard to tell from the close up, but it does look like an anti gravity valve. Used on older gravity systems to prevent circulation to rads during warmer weather.It opens to allow flow through it when pump is on. I'd remove it and clean it up and repair leaks whilst the system is drained.

 

[Terrywookfit]

Yep...Midbrass Dumball valve.

 

[cliffa]

Thanks guys, further investigation with a mirror reveals an arrow pointing up, right way round containing a letter E. So an anti gravity valve it must be. As the rads upstairs do get warm in summer without shutting them off I can deduce it is stuck, not surprising after this time. I'll have to find a replacement. Cheers