I've just fitted a Torbeck value to my cold water tank inlet.
I noticed that water drips out of where the arm holding the ball meets the value while it is filling, and this continues after the main flow through the tube has stopped, but does eventually stop as the arm is forced higher. Is this normal or have I got a dodgy value?
Also is it sensible to cut the filler tube so that the water fills from the top, to avoid stagnation?
TIA
-- Andy
In message , Andy Pandy wrote
It's normal.
Put a hose into the bottom of a water but and watch all the crud from the bottom rise to the top :) I doubt if the water will stagnate if you leave the tube unmodified.
That's quite normal.
You may have a sheet of instructions with the valve showing an exploded view.
The Torbeck is an equilibrium valve. The diaphragm is designed so that when the pressure is equal on both sides, it is against the seat closing it off. There is a metering arrangement through the diaphragm with a hole and depending on the particular valve, a metal needle in the valve body or a little plastic peg. The purpose of this is to allow a tiny flow of water through from the back of the valve to the front. Then in the front part of the body, you have another small hole which is covered by a pad on the end of the actuating arm.
When the float drops, the front hole is uncovered and water can escape from the chamber in front of the diaphragm. Water pressure pushes the diaphragm away and the valve opens fully.
As the float rises, at a certain point the pad on the actuating arm closes on the small front hole and starts to block it. At a certain point, the pressure in front of the diaphragm builds up to nearly as much as that behind and the diaphragm pops back to close off the main flow. However, the metering valve through the diaphragm still allows a tiny amount of water through. To begin with, the small hole at the front won't be completely blocked and there will be drips. Eventually the float rises a little more and the hole is completely blocked and dripping stops.
The effect is more noticable on a loft cold water cistern, simply because the level rises relatively slowly compared with, say, a toilet cistern where it will rise rapidly at the same flow rate.
If it's the type that looks like a kind of flat plastic bag that is forced open by the water, then it should be fine. The water flow tends to make it dance around a bit and stir up the water.
In any case, you are not going to get stagnation.
The colder water coming in from the mains will naturally drop to the bottom.
No, I just got basic fitting instructions, so thanks for the explanation.
Yup, that's the type.
As a matter of interest, what is the purpose of this tube? Is it just to make filling quieter? I assumed it was to stop ripples in the water to prevent the float bouncing up and down, but like you say, the tube agitates the water and causes ripples anyway.
-- Andy
Noise is the reason it's there. The reason it is a flat tube is as a one way anti-syphon device, to stop cistern water being sucked back up the mains in the event of a sudden pressure drop (fire hose in the road outside maybe?
I have had nothing but trouble with bloody Torbeck valves. In principle they seem a good idea but in practice they are very badly made.
Personally I avoid them when possible and fit nice, brass float valves.
Does anyone know if anywhere does a decent (Preferably bras) Torbeck valve?
sponix
What problems have you had with them?
-- Andy
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