Slow filling cistern

H

hansov

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Had a search around this forum and did not find the answer to my problem which is..

Two cisterns in the house are very slow filling. While they fill up so far fairly quickly, mrs. hansov timed a full fill this morning - a total of 28 minutes . Opened the lid and while the final amount of the fill is coming in, it's coming in quite slowly. Anybody got any ideas on what I need to do? Thanks
 
There's a little nozzle / jet thing that the water flows through to refill the cistern and it sometimes gets clogged with grit / dirt in the water coming from the tank - had to change two of these over the past year due to the same problem. There appear to be various sizes - get a large one and you won't have any further problems.

They cost 50c at our local hardware store, but you have to know how to change it yourself or you'll have to call a plumber to do it for you.
 
If you disassemble the valve you find a "valve seat", a piece of plastic shaped like a nozzle, as referred to by delgirl. If you have low water pressure you may need to change the valve seat for one with a bigger hole (for low pressure). Also if you live in a hardwater area you may find that the plastic "spout" which discharges the water when filling may be scaled up. Remove the scale and soak in vinegar to disolve the remainder.
 
on a related point, for cisterns with a handle, taking the lid off is simple.

for cisterns with the one/two buttons on top for full/half flush, is taking the lid off a straight forward matter of just lifting, or do the buttons need to be disconnected in some way first?
 
in my most logical workings out of your problem if both cisterns are slow then the problem is probably not in either of them but where the water comes from for both cisterns. in the attic maybe. is water slow flowing in your sinks.
 
could it just be a design issue, if they are filling up fast to start off with and then slowing down as the cistern gets fuller?

just a thought
 
They fill up fast to start with. You can get another flush fairly fast - it's just the final topping up takes an age. And this a fairly new problem - they used to fill faster. When I get the courage I'll try what Carpenter suggested. Thanks gang.
 
The cistern fill rate will slow down as the cistern fills and the float rises causing the diaphragm valve to restrict flow gradually. So this in itself is not a fault but may be a problem where the valve seat is too small to begin with, particularly in the case of low water pressure. Exchanging the valve seat will quickly reveal whether this is in fact at fault.
 
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