Ideal standard dual flush valve leaking (not overflowing)

[jweaver]

I have 4 identical toilets (which have the Ideal Standard SV92667 Flush Valve) all of which have all had their share of problems over the years due to shoddy installation and wear and tear.

Over time, I have removed the cisterns.. Installed new close couple screws (Which were sticks of rust) swapped the fill valves with Fluidmaster and replaced all of seals and they are perfect.. Except the last one I did this weekend.

Once I re-assembled everything I flushed the toilet and noticed water dribbling down the pan.. This carried on a for a few seconds whilst the cistern filled and once the level got to a point (where there was pressure on the seal) it stopped leaking.

The other 3 toilets don't do this, so I assumed there was something wrong with the cistern and not the valve.

So I swapped the flush valve over with another toilet and the fault followed the valve.. I moved it again, and again it followed the valve.

This would lead you to think the flush valve seal was at fault, but its brand new and perfect... Since the valve itself is the definition of simplicity and just drops the seal into the hole using gravity and then water pressure, I can't see how that could be at fault.. But something is wrong.

I thought about leaving it as it doesn't seem to leak once full.. But I closed off the inlet and left it for 3 days and the cistern totally drained.. So its still leaking a tiny amount.. Perhaps not enough to worry, but it bothers me.

Does anyone have any experience with the Ideal Standard flush valves who might have an idea of how such a leak could happen? I guess its possible its just a faulty seal? I can't see how but its possible I guess.

I look forwards to your thoughts.

 

[Rodders53]

Rubber washer not smooth or the valve plastic mating seat for the washer not smooth? (Possible limescale encrustation you missed?). Also possible that the rubber seal washer is distorted/damaged from new?

I always use a good smear of silicon grease on the housing and washer after a thorough clean up when I replace the washer on my Siamp flush valves here. They aren't identical, but not that dissimilar really.

You don't really want to have a leak of even 2 litres a day... that's 3/4 of a cubic metre per year. In any case it's likely to get worse over time.

 

[jweaver]

I assumed it was the mating surface in the cistern, but the fault follows the valve/seal not the cistern.. So it must be the valve or the seal..

The silicon seal looks perfect.. Totally smooth.. No issues at all but I did think about some silicon grease..

As for the leak.. Don't talk about wasted water.. Before I "serviced" this last cistern I noticed a ripple in the water in the bowl for hours after flushing.. I assumed it was a tiny trickle but finally (After months) got around to blocking the inlet and watching how quickly it drained.. I assumed the cistern would empty over days or weeks.. But it took 20 mins..

I then did the maths and was horrified how much that was.. Don't want to think what that cost me, which is why I want it fixed now... I can't see how the valve body could cause this, as the "plunger" with the seal attached moves freely and drops down hard with gravity.. So it must be the seal.. Might have to buy another just to rule it out..

 

[Rodders53]

Doh! Of course the plastic base is part of the fixed bayonet in the cistern! Sorry!

Genuine Ideal Standard seal or a pattern part from somewhere? May be worth speaking with your supplier of the seal either way?

You've checked the valve's bayonet clip parts are all undamaged as that might allow the seal washer to sit slightly wonky if they are? Not much more I can offer. You have just been unlucky, I guess.

 

[jweaver]

Doh! Of course the plastic base is part of the fixed bayonet in the cistern! Sorry!

Genuine Ideal Standard seal or a pattern part from somewhere? May be worth speaking with your supplier of the seal either way?

You've checked the valve's bayonet clip parts are all undamaged as that might allow the seal washer to sit slightly wonky if they are? Not much more I can offer. You have just been unlucky, I guess.

Genuine seal.. I am waiting for a reply from the supplier.. As you say, perhaps its just a bad seal...

When you say "bayonet" clip, you mean the round piece with a ring of 6 or 8 clips which told the seal to the valve? I was thinking the same, but its clicks in really positively and it looks OK.

Its must be the seal.. Otherwise, why would the leak slow down as the head of water increases, putting pressure on the seal.. Thats atleast what I am thinking

Its a shame the clip holding it in is so hard to get out, or I could swap it with one of the other valves to debug further.

Either way, I am sure I will work it out.. Thanks for you thoughts

 

[jweaver]

Can I ask one last question.. After swapping the valves about, I have found a combination where they all seem to seal.. As a test, I tied off the fill valve, marked and line and left it.. and the water level in 'faulty' valve has dropped perhaps 5mm in 24 hours... But all of the toilets have leaked a little, perhaps dropping a couple of mm.

Before I go overboard with this, I wonder if due to the design of the valve, are they 100% water-tight? Perhaps a tiny amount of leakage is "normal" (or acceptable)?

I just wonder if trying to 100% seal them to get zero water loss is an impossible task and I am just wasting my time?

Is there an acceptable amount of leakage on a flush valve?

 

[ChrisJP]

It seems that new style flush valves and small cisterns were introduced to replace the older siphonic flush systems so as to save water usage.
It's ironic therefore that a lot (if not most) new style flush valves continually leak a little water into the pan. The old siphon systems cannot under any circumstances leak and therefore a more likely to save water usage. Unintended consequencies.....

 

[Rodders53]

Pretty sure my Siamp flush valves don't leak at all.

Dry as a bone at the back of the pan(s)... except when one was playing silly beggars and sometimes not resealing.

I tend to be more aware of toilet leaks as we have a water harvesting system and the cistern refill pump operating makes a small noise (and can be seen on a smart meter IHD).

http://www.ech2o.co.uk/leaky-loos-why-its-not-as-simple-as-faulty-flush-valves is an interesting read.