Siamp WC cistern valve - how does the fill valve work?

Change it and fit a fluidmaster they sell them on here.

 

Item no. 84007

 

Venturi

 

Probably dirt in the stem of the valve.

 

You could get a plumber in

 

You need to lift the float and hold it there for a few seconds, it works on a different principle as a simple ballvalve. Something to do with air going through a tiny hole and building up pressure on the other side to operate the diaphram.

Something like that.

 

Venturi

 

Like i said fit a fluidmaster

 

Has anyone had any problems with Fluidmasters making all sorts of funny noises?

I've had a few recently, one sounded like a hair dryer when filling and one squeeked each time a HOT tap was turned on and off, not the cold though!

 

See the thing is daftydiymostthings - you have to make up your mind:

Do you want to come on a TRADE forum and pick the finest TRADE brains to help you in your DIY?

Or do you want to insult the very same TRADESMEN whose help you need?

You can't have it both ways.

Developing a GSOH and having your own hair and teeth is helpful too.

 

That's nice!

A sincere apology!

 

Well it is a bit of fluid dynamics, the way they work but I doubt that it's a venturi which is to do with pushing a gas or liquid through a choke and there being a resultant reduction in pressure in the medium in the choke area.

The fill valves work as follows: there's a small hole in the diaphragm through which water flows under a slight pressure. There is a second hole in the body of the valve through which the water leaks into the cistern when open. This hole is closed off when the water gets to the required level. Now as a result of the hole in the body being closed, the water is pressurised behind the diaphragm. Now you would be forgiven for thinking that "so what, it's the same pressure on both sides of the diapragm so no net gain". However, because the water on the outlet side of the diaphragm is running out into an open cistern, there is a small but significant difference in pressure. So the pressure behind the diaphragm builds up and closes the diaphragm against the inlet jet. Simple isn't it? It takes time to operate because the water has to flow through the hole in the diaphragm and build up the pressure. Now there are different locations for the exhaust hole, but the mechanism is basically the same. That's why you fit a special diaphragm for low pressure installations and you can't use then with whole house pumps.

 

Properly known as "equilibrium" valves - the best known being Torbeck.

 

The Siamp 99B inlet valve works from 0.2bar of pressure - 20 bar of pressure. It is completely WRAS approved and is the most common inlet valve sold in the UK market.
Can i ask, your toilet is on a mains feed? Its not from a gravity fed tank is it?

It could well be that you have a faulty inlet valve. If you send a copy of your recipt to Siamps office in Manchester they will send you out a replacement f.o.c.