Slooooow cistern

[bsolxiv]

Hi there, firstly I would like to say what a valuable resource this place is.

My problem is my slow cistern, I have a Siamp float valve:

It appears that the water comes through a very small hole and then just kind of dribbles past the lever arm until the float pushes the lever arm against this hole (about 15 mins later).
Is this how it is supposed to work?
I am not in a low pressure area and have not got a loft tank.

Any tips gratefully accepted

 

[JohnD]

you do not say how long it has been like this, and when the valve was fitted.

you need to find the instructions for the valve and see if it has been fitted using a flow restrictor (these are supposed to be fitted if it is connected to mains supply). Thee is probably a choice of high-pressure restrictor and low-presssure restrictor.

you could also look at the filter to make sure it is not clogged with limescale, rust etc.

also check the service valve on the supply pie to make sure no-one has turnd it down (people often do this to reduce plumbing noise)

 

[denso13]

Did it used to work or has it always been like this?

Take the top apart and give all the bits a clean in running water. Put your hand over the part you have taken off and turn the water on slowly to see if the flow reaching your hand is ok. If it is then put it all back together and see what happens now.

If the flow is still not very good with the float valve stripped down it may be partially blocked further back, possibly at a restrictor fitted in the bottom of the valve where the threads are..

 

[JohnD]

http://www.siamp.com/en/index.htm

 

[bsolxiv]

I only moved in a month ago and it's always been like this (previous owner did not mention).
I cannot control the stop tap at the same time to see if the flow of water is good, but when I attempted to unscrew the closing chamber (3) "live", water started coming out pretty fast.

The only way the water comes out is through this very small (pin prick) hole at the back of this chamber.

 

[bsolxiv]

In fact, on the above diagram - if you see the dotted line coming out of #3 to the top left, this is exactly where the water comes out to fill the cistern.
Oh and when I say prick, I mean P r i c k

 

[TicklyT]

I think the way the valve should operate is the float allows water out of the 'pinhole' , which releases the pressure on a diaphragm under the large nut, which allows the main water valve to open.

When the float lifts, it closes the pinhole, and the water pressure on the diaphragm increases, and that closes the main valve.

It sounds like the main valve is either stuck or blocked, or the small float valve is partially blocked so the pressure on the diaphragm isn't released to allow the main valve to open.

 

[denso13]

Yea, what TicklyT said.
On the manufacturers site number 5 on the diagram is called the down pipe. Maybe the main flow should come out at the bottom of it?

 

[bsolxiv]

That definitely sounds like it, there is nothing coming out of the down pipe at all.
Now I just need to work out how to get to the connecting nut under the cistern to get it apart and clean/replace it.
Would the internal valve be very complicated?

 

[JohnD]

no but ask the manufacturers to send you instructions diagram

 

[imroberts]

I'm fairly sure this is the same valve that my cistern has, and takes about 20 seconds to fill.

I know I've got the documentation for mine somewhere so I'll look it out and scan it for you if it is the same

 

[ChrisR]

A Fluidmaster replacement wouldn't be expensive. Tolerances can be tiny and operation enigmatic on these sort of things, so replace if cleaning doesn't fix it.

 

[bsolxiv]

Sorry, forgot to thank you all. Fitted new fluidmaster valve with no problems. Then saw flush was slowly dribbling into toilet (made the cistern refill at about 8 minute intervals - shower time was an experience) so changed the flush too. Now perfect - fills in about 20 seconds.

Thanks again for all your help.

 

[averagediyer]

Just in case anyone else has this problem, the solution is easy. It is more than likely that the diaphragm has split. These can be obtained from B and Q for £2.48. Simply unscrew the bit at the top and replace. Job done.

 

[robwilson]

just bought one today funny enough and fitted it, old one was split and water was spraying out taking ages to refill cistern.
having a bit of trouble getting it to work again though - seems the float is binding a little on the back wall of the cistern so when water level reaches it it doesnt rise to shut off supply and keeps filling. temp solution to put a slither between back to keep it from binding but is there a correct orientation for this, dont think it was binding before i took the valve out and pretty sure ive not changed the way it went back in as the flexi hose at the bottom feed wouldnt allow me to any other way without twisting it??