Identifying the model and GPF of my pre-1999 Kohler flushometer toilet

[Aonyc]

Hello,

I live in a NYC prewar building. Recently our flushometer toilet started leaking in (internally, no water outside, just heard dripping) the flushometer assembly. We had a plumber come in and he recommended replacing the whole flushometer assembly. We live in a co-op and I don't do any repair just for liabilities sake.

Ok, flushometer installed, except now, every tiem we flush it requires two flushes to clear the bowl, even for liquids. What I suspec happened, and conveyed to the plumber is that the GPF of our existing bowl (Kohler from pre-1999 when the apt was purchased) is higher than the GPF of the flushometer they installed. After some back and forth, the plumber agreed to replace the flushometer, but now, I just want to be certain of the GPF requirement of our toilet. There are no obvious markings on the bowl, and there appears to be an old sticker in the back but it's completely detroyed. Is there any way I can ID this toilet to find out the GPF requirement?

 

[Terry]

Either the year, or even a picture showing the entire bowl, with how much water resides in the bowl.
In 1992 we went to 1.6
1985 or so to 3.5
Before that, 4.5
Looking at the Sloan website, options are there for 3.5 GPF and 4.5 GPG
It should be just a matter of changing out the diaphragm. If it's about 1999, then it's the 1.6
(edited)

 

[Sponsor]

 

[Aonyc]

It's definitely pre-1999 because that's when the apartment was purchased, and it hasn't been changed. However, I guess that doesn't mean it isn't from 1992-1999 and may be a 1.6 GPF bowl. All I can say is that they replaced our old flushometer (but left shutoff valve which is what they are now contending is the problem) and now we have to flush twice. the bowl flushes, but the siphon at the end is weak, and liquids and solids both remain in the bowl, requiring another flush. I've attached pics and a video. Would I be able to contact Kohler about this to find the model/specs? Thank you so much for your response.

I put TP in the bowl for simulation

 

[John Gayewski]

I think a 3.5 diaphragm would solve the issue. However they could be right about the valve stop having. If it's stuck partially closed and won't operate correctly, the water needs shut off and that valve would need new internals also. If there are sweat connections under thr chrome changing the valve stop entirely would probably be less risky. I'm sure they are sick of tinkering. It's sometimes better to go with the mindset of just changing everything rather than sniping. It's a tricky situation.

 

[Terry]

I tweaked my post above. It may be a 3.5 bowl.
The shutoff at the wall is the same for all the valves. In fact even the valve bodies are the same, just different parts inside.
I would use a screwdriver to shut the water supply off, rotate off the top chrome cap, and then replace the diaphragm with one for a 3.5 flush.

 

[Aonyc]

Thank you all for you advice.

 

[ToiletEnthusiast]

That's definitely a 3.5 GPF Wellcomme model.