american standard 3 handle shower, balancing C/H water

[pasadena_commut]

American Standard 3 handle shower issue. In a previous thread I posted about problems with the diverter:

https://www.plumbingforums.com/threads/american-standard-3-handle-shower-diverter.9772/

The last time I replaced the hot and cold cartridges on this system it turned out so that opening the cold handle more than just a little resulted in a cold mix because so little hot water was coming out. Since then the rubber must have mashed down on the cold side (handle needed to rotate up by an extra 30 degrees to shut off) so I changed the seats (Danco 30019E) and the Aqua-seal washers (Danco 80410) on both sides. Result, now the cold must rotate a vast amount, more than a quarter turn, before any water would come out. It was the exact same cartridge on that side, just new rubber. Took it out and compared the old rubber with the new. Other than the usual spreading due to being mashed by use it looked the same. Turned the water back on with the cartridges out and observed approximately equal flow on both sides. Put the cartridges in, same problem with C side, not H side. Loosened the nut which holds the cartridge in place and the cold flow improved quite a bit, still not where I want it.

So, is there some trick to putting these cartridges back in about how much to tighten them? The method I used was to retract the center of the cartridge as much as possible, put it back in place, put the nut in behind it, tighten by hand, then with a wrench until "reasonably tight". I didn't use all that much force, about like I would have used for installing spark plugs. That worked for Hot (this time, but not last time) but not for cold (this time, but it did last time.)

 

[TomFOhio]

Those hat washers can be tricky sometimes. Make sure that the washer is all the way tight on
the end of your stem. Push it on hard with your fingers. Try a different washer if still doesn't work.

 

[pasadena_commut]

Those hat washers can be tricky sometimes. Make sure that the washer is all the way tight on
the end of your stem. Push it on hard with your fingers. Try a different washer if still doesn't work.

It was on solidly. The stem with the washer on looks like this one:

https://hdsupplysolutions.com/shop/p/replacement-for-american-standard-cold-aqua-seal-stem-p477501

I'm not entirely clear on how these washers work - never could find a cutaway drawing. Without that it is hard (for me) to explain why loosening the nut makes any difference at all, since my best guess is that the wide part of the washer will be in any case firmly clamped between the brass washer on the stem and the brass fitting in the wall. Why should it matter if that is held with 50 pounds of force or 20? For that matter, what is the point of the brass washer on the stem? If the rubber is clamped, why not just extend the brass barrel of the stem to do that?

 

[Mr_David]

never really had any issues replacing those. Then again I always replace the whole assembly and not just the hat washer
Like Tom said make sure washer is snapped onto the swivel foot end of the stem.
Check inside the valve for rubber that might have got left behind from the any previous replacements.
Retract the stem into the bonnet, full open before you install it into the valve

 

[pasadena_commut]

Check inside the valve for rubber that might have got left behind from the any previous replacements.

I did. There were a few bits of teflon tape, which were retrieved with some tweezers, but no rubber.

Retract the stem into the bonnet, full open before you install it into the valve

View attachment 17178

It was fully retracted.

In the picture...

What is the function of the brass washer? It must do something or they would just have filled the space by making the barrel longer.

It looks like that stem has been greased. I recall reading somewhere that doing so was not a good idea for aqua-seal because if they are sufficiently lubricated they will open by themselves. Water pressure on the rubber apparently can produce enough force to turn the screw in the stem.

Thanks.

 

[pasadena_commut]

So, today the hot valve decided it didn't want to turn off. It was leaking quite a lot actually, no matter how much it was tightened. Took it apart and found nothing in particular to cause it. The valve seat was still tight, it wasn't pitted, there were no tears in the rubber aqua-seal washer. Put it back together and it sealed just fine. However, the flow rate was low again. These things are far too finicky for my taste.

Anybody know what the right part number would be for the more conventional looking stems (just washers, no aqua-seal) which appear like they would fit - possibly like the stems shown here?

https://www.homedepot.com/p/KISSLER...al-Shower-Valve-Rebuild-Kit-RBK4200/204999557

 

[pasadena_commut]

Danco 2K-4C and 2K-4H. These fit perfectly and are not at all finicky like the aqua-seal valves are. It is very nice to be able once again to adjust either side smoothly from nothing to full on. The aqua-seal based valves would go into a state where the flow was more like just on or off.

 

[Mr_David]

Thanks for the update

 

[pasadena_commut]

Recently this tub developed a fast drip (20 drops a second?) and it looked like time for new rubber. Cold water supply off, pull the cold side, replace the washer that contacts the seat with a 1/4M0 (which fit perfectly into the end of the cartridge). Still dripped. Felt the seat and it was rough. Removed it and found some very deep grooves on the bottom (old house, still has original galvanized pipes and very hard water, constant problem with grit in lines). Replaced it (three wraps of teflon tape on the threads). This eliminated the fast drip but a slow drip (about 1 drop/second) remained. Replaced the washer on the hot side. It looked to be in good shape, but what the heck. Felt the seat and it was very smooth all the way around. It looked smooth too but these days I'm not exactly eagle eyed. Put it all back together and the 1 drop/second drip remained. Turned off the hot water at the tank and opened several hot water taps. Waited. Slow drip remained. So it sure seems to be coming from the cold side. The washer letters ("1/4M0") were on the seat side, and slightly raised, but I expected they would smash down enough to seal. I thought maybe the teflon tape had displaced somehow when it was screwed in and it was leaking around the seat, but there was no tape visible around the seat.

Any ideas? Maybe the Danco 2K-4C is supposed to take something other than a 1/4M0?
(Note added: Danco support says that stem uses their part number 35063B, which is a type 0, 17/32 OD, and seems to be the same spec [according to this site: Why do plumbing washers have letters and numbers on them? ] as the 1/4M0 washers which were used. Seems to rule out the "wrong washer" hypothesis.)

Also, on the cold side the flange where the O ring sits had some deposits on it, so it leaked out the handle unless the backing nut was cranked down hard. Cleaned it up with some vinegar which helped but there was still crud on it. Is there a seat tool for something that large? It is more than 1/2" across. I don't think this has anything to do with the slow drip though, as it is on the spout side of the seat.