Gate valve airing cupboard

[ajsdoc]

Hi,

Have replaced the bath taps today (I'll get a plumber next time, but that's another story!)

Anyway whilst isolating the supplies to the bath in the airing cupboard (gate valve on cold supply from cold water cistern in loft to bath and cold feed to HW cylinder) I noticed another gate valve which on trying to turn was seized.

I thought "can't have that" and so set to freeing it with penetrating oil and a spanner which I did. Trouble is I'm now not sure whether it was in the open or closed position before I started.

I've been in the loft and the valve is on the pipe that comes out of the bottom of the "small tank" in the loft and so I presume it to be the central heating feed? I also presume it should be fully open?

Just for peace of mind can someone confirm I'm right? I assume it's use is for when draining down the central heating to avoid the need to tie up the ballvalve in the small tank??

I appreciate any replies to a likely numpty question.

 

[D_Hailsham]

I've been in the loft and the valve is on the pipe that comes out of the bottom of the "small tank" in the loft and so I presume it to be the central heating feed? I also presume it should be fully open?

You presume correctly.

Just for peace of mind can someone confirm I'm right? I assume it's use is for when draining down the central heating to avoid the need to tie up the ball valve in the small tank??

Got it in one!

Leaving it closed would mean you had a sealed system which would be dangerous without the necessary safety valves. This is why some water authorities prohibit a valve on the pipe from Feed tank to the heating system.

 

[45yearsagasman]

Technically speaking it would still have an open vent so it would not be completely sealed, but as DH said it must be open when system is in use.

 

[Spanglesnatch]

Best be carefull in case its a combined feed/vent, quite common with Potterton Profiles. Cant believe it would have a gate valve fitted though. Leave open and take the handle of in case its inadvertantly turned off in future

 

[D_Hailsham]

Technically speaking it would still have an open vent so it would not be completely sealed, but as DH said it must be open when system is in use.

Of course! I was thinking of my system, which is combined F&V, so had forgotten about the separate vent pipe.

 

[ajsdoc]

There is a separate pipe which bends over the top of the "small cistern" in the loft (and one over the bigger one for that matter).

I assume that means a separate vent?

 

[D_Hailsham]

There is a separate pipe which bends over the top of the "small cistern" in the loft (and one over the bigger one for that matter).

I assume that means a separate vent?

Yes, they are both vent pipes. The other one is for the HW cylinder, it comes off the top with the HW outlet.