Jammed stop cock

[MadAlicesDad]

I want to reinstate an old outside toilet, but I can't get the water supply working.
The supply pipe comes through the floor to a stop cock about 6 inches from the floor, mounted vertically. The tap is free to turn but no water flows. I've removed the pipework above the stop cock and can see water in the stop cock body. This suggests that the supply is still connected and water is seeping through (else the water would have evaporated away long ago) but the stop cock valve is seized.
I've tried heating it and tapping it but it made no difference.
I can't remove and replace the stop cock because I don't know where/how to cut the water supply off. Are there any tricks of the trade to free up jammed stop cocks with the supply still connected?
Cheers,
Mike

 

[seco services]

freeze the pipe.

 

[MadAlicesDad]

I did think of that and although I've done jobs using pipe freezing successfully on 15mm pipes, I've had an almighty failure on a 22mm where I hadn't given it enough freezing (the can ran out) and I had to resort to draining the system down. I don't want to do the same again, especially as (if it is connected) it will be mains pressure and I have no fallback plan to cut the supply off.
The inlet is a thick lead pipe (I think) with limited access and there is no way of guaranteeing the water is frozen.
This would be a (very) last resort. I'd probably consider getting a professional in before I did that!
Cheers,
Mike

 

[seco services]

get a plumber with an electric pipe freeze, that will keep it frozen alday long.

 

[MadAlicesDad]

I can't afford a plumber to keep it frozen all day long at their hourly rates But as I said, I would resort to that if there are no DIY options.

Mike

 

[BingoBongo]

if the head is turning then it has snapped off internally.

turn off in street and replace valve.

 

[keego]

The best way to check is to knock a small panel pin in the pipe before the stoptap (honestly!) If you then get water gently tap over the lead around the hole with a ball pein hammer to form a seal around the hole, just make sure you cut that piece out if you replace the stoptap.
The way we used to do it if we couldn't shut off was to don the waterproofs & cut it with a pair of poly cutters then have a leadlock with a stoptap fitted to it & a long piece of pipe on the other end, as soon as you put the leadlock on it will take the water away from you.

 

[stephenf8542]

Go toHSS or your local hire company and hire a freezing kit.Its a lot cheaper than a plumber but its the same kit

 

[MadAlicesDad]

if the head is turning then it has snapped off internally.

turn off in street and replace valve.

It will turn both ways for several turns, but not indefinitely, so I don't think it's snapped, and if I knew where to turn it off, I wouldn't have to ask how to do it with the water connected!
The tool hire is an option, but I'll try the panel pin trick first.

Cheers,
Mike