Torbeck valves at very low pressure

Apr 23, 2006 8 Replies

Do Torbeck valves not work at very low pressure?



Reason I ask is that we just got back after a week away and the cold water tank overflow was dribbling. Odd, I thought, as I had turned the water off before going. It seems I hadn't turned it off completely, and a slight dribble was getting through.



But after turning the water on fully, the overflow stopped dribbling, and it's been OK since! So the valve now seems to be functioning OK under full water pressure.



TIA


-- Andy


Why do you turn the water off if you go away for a week if you don't when you go out during the day? The valve will work with whatever water pressure there is - within reason. Maybe you need to get the main stop tap fixed first.

Possibly not. They use the water pressure to shut off the water. IIRC, there's a tiny let-through hole which is opened to release the main pressure holding the valve closed. If the mains flow is restricted such that the pressure is low with flow though the tiny let-through hole, I could well believe it might not be able to close off. Some of the ball-valves work the same way (but not all).

Same applies to the SureStop remotely operated valves. If you try to test one by cautiously cracking an isolating valve upstream, it won't switch off. It needs some pressure to provide the 'motive power'.

They will work over a wide pressure range. At higher pressures and flows there is a restrictor which is a spiral gizmo that fits into the inlet. This is to allow the valve to cope with higher pressure/flows.

The most likely reasons for what happened are that a piece of grot entered the valve and stopped it closing against the seat properly (unusual because normally it is flushed through), or that the diaphragm has become stiff with age and needs to be replaced.

I would suggest turning off the water, removing the front of the valve and then flushing the valve through in case there is more grot.

If it happens again, then try replacing the diaphragm.

One very good reason for so doing (& likewise with other equipment) is that if disaster strikes whilst I'm out during the day, chances are I won't be away long or else someone will be able to track me down & I'll be able to hotfoot it back.

If I've gone off to the ends of the earth for several days, chances are that I'll be all but uncontactable and certainly not able to hotfoot it back. Which could leave a 3rd party having to cope with a major disaster such as a burst, overflow or freeze up. Certainly more cost, more intrusion.....

Because a slow leak has the potential to do a lot more damage in a week than over a few hours.

A couple of years ago my toilet tank started leaking, the valve was faulty and was letting drips through, and the water was leaking out of the flush handle joint, which wasn't sealed properly and was at a lower level than the overflow pipe. I noticed a pool of water on the floor after getting back from work, no damage, but if I had been away for a week it could have caused some damage.

Been experimenting - just need to turn it off a bit tighter.

-- Andy

Yup - fitted one of these.

That would make sense - it might not have been flushed through because of the very slow flow rate. On turning the full water pressure on, it would have been flushed through.

It's only a year old...

Well it's OK now so I guess any grot has already been flushed through.

Thanks - I'll keep my eye on it...

-- Andy

In article , Andy Pandy writes

There's a gizmo called a pipeguard for folk worried about pipes bursting, leaks etc, it detects abnormal flow and shuts the water off.

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