My toilet cistern currently has an Armitage Shanks dual flush valve like this one:
Would I be able to fit the Fluidmaster model instead?
I believe the hole at the bottom is standard, either 1.5 or 2 inches.
MM
I don't see why not. I've recently replaced two conventional syphon flush mechanisms with those very Fluidmaster valves.
The 1.5 or 2 inches refer to the BSP size of the threaded outlet pipe - not to *actual* inches. Both my original valves were 1.5" BSP requiring a hole of approx 2" in the cistern. The Fluidmaster valve is 1.5" BSP, but it comes with a large washer (which I didn't need) to enable it to fit cisterns previously fitted with 2" BSP valves.
How do you currently operate your existing valve. Is there is a hole somewhere in the cistern itself or in the lid, with a button on some sort?
The button supplied with the Fluidmaster will fit either a smallish hole previously occupied by a flush lever - in which case most of the button remains outside - or a much bigger hole - which allows the button to be recessed, with only the flange outside. There's a large picture of a replacement button on the SF page you cite. The large cylindrical cover just below the flange can be discarded in order to allow the button to be recessed if you have a large enough hole. The cage nut on the inside can be fitted either way round depending on how much of the button is inside.
See my comment below.
The cistern lid has a centre-mounted button with a round push flange underneath to push on the current Armitage Shanks flush valve (a round disk). The hole in the ceramic lid should be able to accommodate the new cable button, I should think.
I have also seen in a YouTube video how the button can be recessed as you describe.
I'm pretty sure, too, that the unit will fit, but this is one of those jobs where once the cistern and old valve have been dismantled, only then might one discover that additional parts are needed and one is left without a toilet in the meantime.
However, since I have a second toilet downstairs, this isn't really a problem here.
Thanks for the feedback. I've never done this yet. I've replaced an inlet valve twice, no probs, but never a flush valve.
MM
The only thing to watch then is that you've got sufficient vertical clearance because the button will end up directly above the flush valve. The top of the main part of the valve is about 190mm from the bottom of the cistern, and the cable attachment part of the button will extend down by about 90mm from the underside of the lid. So you'll need an internal height of at least 280mm.
My pleasure.
Is it a close-coupled cistern? If so, you'll have to separate the cistern from the pan in order to remove the flush valve. If that is the case, make sure you replace the rubber doughnut. And if the metal plate and fixing bolts have rusted up - as one of mine had - replace them too.
And as in my case, be prepared to buy a Dremel as the only tool small enough to get at them in order to destroy the rusted nuts.
I've just measured 290mm from the bottom to the flange. The lid is recessed, so that the current button adds about 30mm to that measurement.
That was going to be my next question. Yes, it is close-coupled, and I also wondered about the seal between the cistern and the pan. I won't know till I dismantle it what the condition is, but I'm going to wait until a weekday, because Screwfix in Spalding only opens until 4pm on Sundays. I've already test-loosened the two screws holding the cistern to the bathroom wall, and they were easy to loosen. I've tightened them back up again prior to the actual job, probably later in the week.
One other question right now: Should the large hexagon or knurled locknut at the bottom of the flush valve be hand-tightened only?
MM
My cistern's bottom attaching bolts (2 off) have wing nuts. The bolt threads *are* rusty, so I will have to use WD40 and jiggle the wing nut back and forwards to act like a die. If they won't budge, I'll saw them off with a junior hacksaw, for which there is just about room.
MM
I managed to generate enough space above the nut on one side of mine to get a pad-saw in. By lying in a very awkward position, I eventually managed to saw part-way through the bolt, and then snap it off. The other nut came off ok.
I had even more fun with one of the screws holding the cistern to the wall. One came out ok, but the one behind the inlet valve was completely rusted up. Its head snapped off ok, but the shank of the bolt was rusted solid to the hole in the cistern. I had to use a lot more force than I was happy with, trying to lever the cistern away from the tiles - and eventually the plug came of of the wall, leaving the screw still firmly attached to the cistern. [It was easy to remove once the cistern was off].
As far as I'm aware, the cistern hadn't been off since it was installed well over 20 years ago. What should have been a half-hour job ended up taking me all day. Glad I wasn't paying someone by the hour!
No harm in getting the WD40 on now, even if you are going to do the job later in the week.
Actually, having just had another look under the cistern, I don't see how the cistern is actually attached to the pan.
There is indeed one of these funny brackets:
with the two bolts and wing nuts, but how does that plate actually fix the cistern and pan together?
MM
I can't remember, but I know it will be clear once it is all in pieces!
Mine has the opposite problem, the wall is ancient (>300 years), and there is nothing solid behind the cistern, only loose lath and plaster, so the mounting screws are for location rather than solidity. The cistern is supported on wooden blocks sitting on the sturdy pipework box, which works fine.
One day ......
Fluidmaster are not very specific about that. They tell you to push down on the valve (presumably to compress the thick rubber gasket) while tightening the nut - but they don't tell you *how* tight to do it up. I tightened mine with my hand and then gave it a bit more with a suitable wrench, without using too much force.
The bolts have domed heads with a square bit below the head - like coach bolts. These fit into slots in the plate - with the squares preventing the bolts from rotating. That is, of course, until you succeed in rounding off the square bit when you attach your Mole Wrench to the rusted-up wingnuts!
If you know that your bolts are rusted up, I would recommend replacing them anyway rather than trying to re-use them. A complete close-coupled kit consisting of the plate, bolts and rubber doughnut doesn't cost very much.
If the bolts and wing nuts are both steel you might be better off using a dedicated penetrating oil like Plus Gas than something like WD40 (a water dispersant with some penetrating properties).
I think on the last one I put together I coated the threads with Coppaslip. ;-)
Cheers, T i m
There's a better illustration of a kit here:
The large hole in the plate fits over the flush valve's outlet pipe and is held in place by the large nut - being careful with the alignment.
The doughnut then fits over the large nut.
You then slide the bolts into the slots so that they dangle down from the bottom of the cistern.
Now the fun bit . . . You lower the cistern onto the pan, making sure that the bolts pass through the holes in the pan, without being able to see what you're doing - particularly if the cistern is heavy, as both of mine are. You'll be lucky if you achieve that in one attempt without at least one of the bolts falling out.
Once you've done that, loosely fit the rubber washers, metal washers and wing nuts and then jiggle the cistern a bit to centralise the doughnut in the pan inlet. Then fully tighten the nuts (by hand).
So, to answer your original question, the plate is fixed to the cistern by the big nut and to the pan by the two bolts - thus fixing the cistern to the pan.
Like this one?
MM
Gawd, I remember Plus Gas from my apprenticeship days! Yeah, good idea. I'll get some.
MM
That's why I'd like to DIY this job, if poss, as I've seen quotes on the internet for up to £100. The parts (from Screwfix) are as cheap as chips (Fluidmaster).
MM
Ah, I thought the large nut just held the flush valve in the cistern. Is there a pic anywhere that shows this, maybe in cut-away view? I'll see soon enough once I've got it all dismantled, but I do rather like knowing exactly what lies ahead before starting work.
I'm assuming that a coupling kit (metal bracket and doughnut) is suitable for pretty much any close-coupled toilet?
MM
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