Toilet Cistern Slow Filling - Advice Please?

DPinBucks

Distinguished Member
I wonder if anyone can help with this.

The picture is the cistern in our downstairs toilet. It's a design I've never seen anywhere else. The flush is via two vacuum buttons which work the red-topped pistons; for short and full flush. They have never worked well, and we may decide to replace the whole thing anyway, but the main current problem is that filling takes ages; more than an hour. The trickle of water is almost undetectable.

The inlet water pipe is obvious. Below it (ringed A) is what I think is a shut-off valve, but as the water flow is so slow it is difficult to be certain. It rotates a quarter turn between, I suppose, On and Off. It's in the On position now, I'm pretty sure. Just visible coming out of the bottom is a flexible pipe which emerges at B to attach to the float valve. Filll water from the valve comes down the plastic tube C.

The problem is, I have no idea why there almost no flow. I don't see how it can be the copper inlet pipe, as that also serves a wash basin, which is fine. So it could be the shut-off or the float valve. At first glance everything seems to be in good condition. There is a little scaling, but not much; it's fed with softened water.

Another problem is that it's hidden behind a false back to the toilet itself and is almost impossible to get at.

Ideas?
IMG_0321 a.jpg
 

MrFraggle

Distinguished Member
Perhaps a bit of dirt is blocking the flow and the only way to find out is to shut off the water and remove the part. But of course that is fraught with danger unless you are reasonably experienced in plumbing.
I swapped a sink tap over yesterday which I thought would be straightforward after looking at videos , took me 4 and a half hours.

Edit: What are B and C?
 

NeverEden

Distinguished Member
Hi

I'm not a plumber but like to find the root causes of DIY issues in my house. A few years ago I had a similar problem involving an in wall cistern with filling issues as well as continuously running so it made me want to figure out how the whole thing works and eventually replace it myself. Funnily enough, my local plumber asked me how I managed to sort it out as he was used to the traditional ball cock ones.
What I would do first is turn your mains water off and then remove the connection unit to/from (A). Then turn the mains back on. If you see it flowing quite freely out the copper piping then you can narrow it down to something up with the valve cistern unit. In which case they can be very easily dismantled and checked/washed for debris etc.
If you need to replace it, they are quite cheap, mine was £10 from B&Q.
 

DPinBucks

Distinguished Member
Perhaps a bit of dirt is blocking the flow and the only way to find out is to shut off the water and remove the part. But of course that is fraught with danger unless you are reasonably experienced in plumbing.
I swapped a sink tap over yesterday which I thought would be straightforward after looking at videos , took me 4 and a half hours.

Edit: What are B and C?
Thanks.

Yeah, tell me about it! :(

B is the end of a standard flexible 15mm pipe which goes across the bottom of the tank from the inlet valve A. You can just make it out underneath A. C is a soft plastic tube attached to the outlet of the float valve. Fill water runs down it into the tank until the valve shuts it off. It's so there's hardly any noise when the tank fills. It's a little bit grungy, but is certainly not blocked.
 

DPinBucks

Distinguished Member
@NeverEden: thanks.

In fact I'm pretty OK with plumbing, and have fitted toilets & cisterns several times. This one, though, was done professionally, and quite well in my opinion. I have no complaints about that.

The problem is that I can only get at it from the top without dismantling the whole false wall structure which hides it. The wall's only plywood, not tiled, but it won't come off without cutting it away. I'd have to do that if I decide to replace the whole cistern, which to be honest I may well end up doing.

The only two things I can think of to do while it's in situ is to check the mains pipe, as you suggest, and to take off the top of the float valve to see if anything's stuck.
 

Wahreo

Distinguished Member
Yes A looks like the quarter turn shut off valve and the most likely cause of the poor flow is within the float valve.

It needs dismantling. It looks like the arm needs removing and the large nut unscrewing.

The bit being the large plastic bit above the circle in the picture.

It could also be a strainer somewhere on the inlet to the float valve.
 

IronGiant

Moderator
Long shot, but you say there is a flexible pipe between valve A and the float valve, have you checked it for kinks?
 

Wahreo

Distinguished Member
I didn’t read that. The section where the flexible hose joins onto the inlet valve might be where the strainer is.
 

DPinBucks

Distinguished Member
Long shot, but you say there is a flexible pipe between valve A and the float valve, have you checked it for kinks?
Yes, I have, thanks. It's a standard 15mm compression flexible pipe, covered in braided metal, and they don't kink easily, but I did check it. If it is blocked, I can't remove it to check without, as I say, dismantling the whole toilet installation.
 

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