Cistern Water Suppy Issue

[Plumb37]

Hi,

I’ve just replaced my WC cistern fill valve (bottom feed) with a brand new one from Toolstation as the cistern wasn’t filling up. The water feed to the cistern has an isolating valve which seems to be working fine.

After fitting the new valve the cistern filled up and flushed 4/5 times as it should do but then just stopped filling up reverting back to the original problem.

Before fitting the new fill valve I changed the washer in the original one and the same thing happened.

This makes me think there must be an issue with the water supply coming in but I have never seen a cistern fill correctly 4/5 times and then stop filling.

Any advice would be really appreciated.
Gary

 

[rpm]

Check the float isn`t getting snagged on anything in the cistern.

 

[Plumb37]

Thanks for the reply.

The float is ok and there is plenty of clearance. I had the same issue with the original fill valve & float which is why I changed it. I thought this may have solved it.
What’s confusing is it all works as it should do for 5 flushes and then the water pressure seems to drop and it trickles.

 

[rpm]

Guess you need to trace back to where the water is supplied from.

 

[townfanjon]

Who the manufacturer of the valve ?

 

[Rob Foster]

Hi,

I’ve just replaced my WC cistern fill valve (bottom feed) with a brand new one from Toolstation as the cistern wasn’t filling up. The water feed to the cistern has an isolating valve which seems to be working fine.

After fitting the new valve the cistern filled up and flushed 4/5 times as it should do but then just stopped filling up reverting back to the original problem.

Before fitting the new fill valve I changed the washer in the original one and the same thing happened.

This makes me think there must be an issue with the water supply coming in but I have never seen a cistern fill correctly 4/5 times and then stop filling.

Any advice would be really appreciated.
Gary

I wonder if this cistern is tank or mains fed > if its mains fed then it should refill grand style however if its a tanky one then this might be the answer.send us some pics hey

 

[DAVE01]

Hi,

I’ve just replaced my WC cistern fill valve (bottom feed) with a brand new one from Toolstation as the cistern wasn’t filling up. The water feed to the cistern has an isolating valve which seems to be working fine.

After fitting the new valve the cistern filled up and flushed 4/5 times as it should do but then just stopped filling up reverting back to the original problem.

Before fitting the new fill valve I changed the washer in the original one and the same thing happened.

This makes me think there must be an issue with the water supply coming in but I have never seen a cistern fill correctly 4/5 times and then stop filling.

Any advice would be really appreciated.
Gary

Best thing to do is put a penny valve on cold supply to cistern close penny valve turn back on to see if there is a issue with water supply If cold to cistern and its a standard ball cock it should have a low pressure orfice if its comeing from cold mains should be high pressure orfice use a torbeck valve it comes in a kit with high and low pressure and medium pressure orfice

 

[Best]

Best thing to do is put a penny valve on cold supply to cistern close penny valve turn back on to see if there is a issue with water supply If cold to cistern and its a standard ball cock it should have a low pressure orfice if its comeing from cold mains should be high pressure orfice use a torbeck valve it comes in a kit with high and low pressure and medium pressure orfice

Most plumbers now don’t use the Torbeck valves as they started to give a lot of trouble when they were redesigned.
Fluidmaster Pro45b (brass tail) is one of the preferred valves

 

[Plumb37]

Thank you for the responses.

This is the valve I fitted:

 

[rpm]

Nice valve, I'm happy to fit them

 

[Last Plumber]

Perhaps there is a foreign body in the supply to the valve?

 

[Plumb37]

Thanks I’ll check that.

It’s strange how the original fill valve and float filled the cistern a couple of times and then stopped to a trickle. Then the brand new fill valve in picture above filled the cistern 5 times and then stopped working.
Two completely different valves doing the same thing so can only be the cold water supply.

What difference would it make if it’s mains fed or tank fed apart from pressure?

Thanks
Gary

 

[Plumb37]

Nice valve, I'm happy to fit them

Really good quality and easy to fit.

 

[Plumb37]

Best thing to do is put a penny valve on cold supply to cistern close penny valve turn back on to see if there is a issue with water supply If cold to cistern and its a standard ball cock it should have a low pressure orfice if its comeing from cold mains should be high pressure orfice use a torbeck valve it comes in a kit with high and low pressure and medium pressure orfice

Thanks for your reply.
The cold feed has a isolating valve already fitted which I turned off to fit the new fill valve and float. When I turned it back on the cistern filled within a minute and worked for 5 fills and flushes. After that its lost pressure and now is not filling. I can’t understand how it can work and then stop with a constant supply.

 

[rpm]

Two completely different valves doing the same thing so can only be the cold water supply.

What difference would it make if it’s mains fed or tank fed apart from pressure?

Thanks
Gary

I can’t understand how it can work and then stop with a constant supply.

Mains fed should give a constant feed however if it is tank fed then perhaps, just perhaps the problem is there.
Try holding the float down and keep it down and flush the cistern when the water is high enough - I expect the water to stop entering the cistern after your 5 flushes and the fault lies within the tank feeding the cistern.

 

[Plumb37]

Mains fed should give a constant feed however if it is tank fed then perhaps, just perhaps the problem is there.
Try holding the float down and keep it down and flush the cistern when the water is high enough - I expect the water to stop entering the cistern after your 5 flushes and the fault lies within the tank feeding the cistern.

Ok many thanks I’ll try that when I get home.

 

[Ric2013]

Another suggestion is that there could be a foreign body in the water and it is obstructing the flow through the isolation valve. When you worked on the system, the FB [edit: foreign body] fell down the pipe and then it came back up with water flow. Mind you, this is a very long shot!

 

[rpm]

Another suggestion is that there could be a foreign body in the water and it is obstructing the flow through the isolation valve. When you worked on the system, the FB fell down the pipe and then it came back up with water flow. Mind you, this is a very long shot!

English please Ric, FB?

 

[Ric2013]

Apologies for confusion. FB was intended to be Foreign Body, as I'd already used the term and thought it was ***bersome enough having to write it once.

 

[rpm]

How about connecting a pipe to the cistern feed and running it to the toilet or basin then open the isolating valve and see what happens over time?

 

[Plumb37]

How about connecting a pipe to the cistern feed and running it to the toilet or basin then open the isolating valve and see what happens over time?

I’ll try that as well. Thanks

 

[Deleted member 96286]

If your bathroom is fed from the same cold water supply, try running the cold bath tap and see if it spurts out after a while. Could be air getting trapped in a dip in the gravity fed cold water supply from the storage tank, especially if the supply was turned off. Check the gate valve too, these are notorious for jamming and may not be fully opened. Running a 3/4 bath tap from the same line should help clear any air. I much prefer the Fluidmaster fill valves, as they are fit and forget.

 

[Plumb37]

Thank you for all the advice it really is appreciated.
I believe it may have been air in the feed as after running the supply into a bucket several times it appears to have corrected itself and is now filling up nicely.

 

[rpm]

Yee Hi!!!!!

 

[Welder]

Ric's answer is my 'goto'. Don't tell him tho
Had that happen too many times NOT to check.
100% issue is in supply to cistern.
Best to disconnect iso, put flexi on it and into bucket then turn on water to push through 'crap'. Most of time it drop away through water when pressure is off so you must do the flush thing to push it out.