Water Supply Valve - how much to open?

wazza

I have the mains cold water suppy valve in the basement of the house. Over a month ago i had to turn off the supply in order to change some tap washers. Now the valve drips a bit of water. Have a bucket underneath to catch the drip. I am not worried about it since the drip rate is very small.

I was wondering do you fully open the valve or simply fully open and turn it close a bit?

macman

Open it fully, then turn back about a quarter turn.

sillygoose

Presume you have something like this...


Its not unusual for them to leak after being disturbed, has the full main pressure on it. The seal material is probably a bit 'tired' all you need do is compress it a bit. The nut (5 in picture) at the base of the handle stem needs a little tighten with a suitable spanner (clockwise from above) - carefully, probably only quarter turn and see how it goes before any more.

wazza

I am going to leave it as it is. Knowing my luck i will create a problem and at this time of the year it will be hard to get a plumber.

It will be added to my ever increasing to do list

macman

It's a job that will take you less than a minute to do...

wazza

macman wrote: »

It's a job that will take you less than a minute to do...

I know the job will take a few seconds to tighten the nut but if it breaks i will have an indoor swimming pool in the basement.

The_Economist

Wazza what you can do, as i have had to do on my mains cold water feed tap to stop it leaking is undo nut 5 in sillygoose picture and wrap round some PTF tape and do up the nut. You can do this live, and it worked a treat for me it stopped the leak.
HTH

wazza

The_Economist wrote: »

Wazza what you can do, as i have had to do on my mains cold water feed tap to stop it leaking is undo nut 5 in sillygoose picture and wrap round some PTF tape and do up the nut. You can do this live, and it worked a treat for me it stopped the leak.
HTH

Don't you have to turn off the mains supply from outside the house?

The_Economist

No. I done it live. I didn't touch the mains tap outside on the pavement. What you could try is turn off the tap that is leaking, undo the nut (number 5 in sillygoose pic) put PTF tape on, do up nut see if leak stops. If it still leaks, open said tap undo nut (number 5 in sillygoose pic) and put PTF tape on then tighten up nut.

sillygoose

The_Economist wrote: »

No. I done it live. I didn't touch the mains tap outside on the pavement. What you could try is turn off the tap that is leaking, undo the nut (number 5 in sillygoose pic) put PTF tape on, do up nut see if leak stops. If it still leaks, open said tap undo nut (number 5 in sillygoose pic) and put PTF tape on then tighten up nut.

Except if he is going to do this, it involves undoing the nut and doing it up again anyway! - in the first case it probably just needs a quarter to half a turn tighter.

Basically under this nut is a soft seal, it seals around the stem of the tap. The tighter the nut (5) the tighter it compresses the seal around the stem. Its not that easy to overtighten or break as its just squashing a squashy material. Seal just has to be tight enough to resist the pressure pushing water past it. Overtime like any compressed material it loses its springy but the minuscule gap probably seals itself with crud and lime-scale over time. Disturbing it by turning tap on/off breaks the lime-scale seal and it leaks.

A small tighten usually takes up the slack in the tired seal, job done.

The_Economist

sillygoose wrote: »

A small tighten usually takes up the slack in the tired seal, job done.

Probably if thats all it needs. If it still leaks after tightening up the nut as you suggest, i would try the PTF route before having to get in a plumber, or changing the offending tap. Hence money saved! :beer: