Conceala 2 (sv93467) dump valve issues!

[Dilalio]

Anyone else had an issue with one of these?

Ideal Standard 1.5 Dual Flush Valve (SV93467)

First visit I cleaned up the base washer of limescale and reseated it. Fine for a week then started letting by again.
So, new washer and clip, again... Started letting by.

Ordered whole new valve and went to fit it this morning. Should have been 5 mins job but the new unit still let by and I had to feck about for an hour. Changed the inlet valve diaphragm as it was filling so slowly I assumed that new water was just flowing down into pan before enough head and weight of water pushed down on the dump seal, to stop it letting by.

This eventually worked by overcoming the water running into the pan, but surely that's not how this valve should operate!

I got it to hold but its bugging me and am not happy with it! I could pop back and smear silicone grease over the dump seal but that's not proper is it!
Can't see how this part from a decent reputable manufacturer shouldn't work as it comes.

Any other ideas? Obviously, the existing base part of the valve was used and I just twist-locked the upper assembly into it. Could it be a limescale issue with the bottom assembly not having a perfect mating face?

Cheers for any input. I hate a £35 spend on a part that doesn't fix an issue

 

[ShaunCorbs]

Have you replaced the push as they go wrong eg not fully extending out / sticking

 

[Dilalio]

They're air buttons (dual flush) and it happened whether or not they were connected via the pneumatic tubes.

Ta for stepping in

 

[Dilalio]

This is the flush plate...

Ideal Standard Conceala 2 Dual Flush Plate S4399AA | PlumbinBits

 

[ShaunCorbs]

They're air buttons (dual flush) and it happened whether or not they were connected via the pneumatic tubes.

Ta for stepping in

Yes do they extend fully and don't bind up etc

 

[Dilalio]

Yes do they extend fully and don't bind up etc

They seemed fine. No detritus dropped down in them, travel and spring good and bellows smooth. Didn't scrutinise them too much as the issue existed whether I had the push plate connected or not

 

[Dilalio]

Hmmmnnn... Thinking about what you said... Do you think the valve might only function correctly when the hoses are connected to the bellows (buttons) so that resistance of the trapped air prevents the sealing washer from lifting slightly under buoyancy of the rising cistern water? Or am I overthinking it

 

[ShaunCorbs]

Hmmmnnn... Thinking about what you said... Do you think the valve might only function correctly when the hoses are connected to the bellows (buttons) so that resistance of the trapped air prevents the sealing washer from lifting slightly under buoyancy of the rising cistern water? Or am I overthinking it

Yes spot on

 

[Dilalio]

Yes spot on

Lol! Which bit.. The vacuum or overthinking it?

I don't want to charge customer for a new push plate (@£30) if it's not that. So maybe I'll just bung the ends of the pneumatic hoses as a test, if she has further issues with it. That should rule them in or out you think?

 

[ShaunCorbs]

Lol! Which bit.. The vacuum or overthinking it?

I don't want to charge customer for a new push plate (@£30) if it's not that. So maybe I'll just bung the ends of the pneumatic hoses as a test, if she has further issues with it. That should rule them in or out you think?

The plate