Difficult to set desired temperature

[David M. Karr]

I've lived in my house for 25 years, and the shower fixture is still the original. The only thing that wears out is the "temperature control dial". The original lasted for many years and finally wore out. I tried to find a replacement in a couple of local home supply stores, but they all seemed to think those parts aren't made anymore. For a few years after that, my temp control dial was a wrench that sits on a shelf next to the shower. It worked well enough, although obviously an obnoxious solution.

Recently, I found that I was unable to get more than lukewarm water. The water pressure was fine, but the temperature was not. I gave in and called in a plumber, to fix the temperature problem, and hopefully provide a solution for the missing temperature dial. He took one look at the fixture and said he had a temperature dial for this fixture in his truck. He also said these parts are certainly still being made.

He installed the new dial and after what I now realize was too brief a test, we verified that we could now get hot water, so I paid for the visit and he left.

In later days, what I realized was that I now have very little control over the water temperature. The water is hot, even slightly too hot, and moving the dial barely has any effect on the water temperature. I am unable to lower the temperature to lukewarm or colder.

I'm guessing this must be a problem with the cartridge. Do these symptoms indicate that the cartridge likely needs to be replaced?

I'm attaching a few pictures of the fixture. I haven't attempted to extract the cartridge yet, although I assume the first step is undoing the small screw at the base of the fixture.

 

[Jeff Handy]

I am thinking that the brass screw is likely there to adjust the high limit for temperature.

I don’t know how exactly, but if you loosen it and play with it you might see what needs to be moved around.

Just a guess, so feel free to ignore!

PS cover the drain while working on it, or little parts might go bye-bye.

 

[David M. Karr]

Thanks for replying, but that small screw is there to keep the wide housing on. All the water control itself should be isolated to the cartridge.

To reiterate, i believe I have all the information I need to replace the cartridge, but I'm looking for confirmation that a faulty cartridge might be the cause of the lack of control of temperature. Proper replacement of the cartridge does involve some non-trivial steps, and I don't want to go through that if I don't have to.

 

[Jeff Handy]

An old worn out cartridge can definitely cause too much hot or cold water, or lack of mixing control.

Ceramic or rubber parts inside can be eroded away.

I don’t recognize the cartridge, but many folks on here might know the brand and model.

Or take it to a plumbing supply house, they will likely know it or find it from a chart.

 

[Jeff Handy]

And don’t rule out that the brass screw, at approx the 2:45 clock position, is not ALSO involved in hot water setting, as in HIGH MED LOW hot temp limit.

Not saying it is, but keep an open mind.

 

[David M. Karr]

I found a video that seemed to match my exact hardware, and it's clear to me that replacing the cartridge is within my capabilities, although I can't be certain exactly what model number I have installed, and whether I'll be able to find that in the home store.

In any case, I've decided to let this stay as it is for now. I took off the flow and temp dial and reattached them carefully, and I think I'm getting consistent temperature results now. I don't know whether the plumber installed it incorrectly. I know that he didn't install it with the "TEMP" label right on the top, which might have confused me a bit when using it. When I reattached it, I made sure everything was lined up vertically.

 

[Rickyman]

The brand name is Mixet. Home Depot stocks cartridges and trim in my area.

 

[Jeff Handy]

If your new Mixet knockoff cartridge still does not give full range hot to cold control, this company makes an improved cartridge.

They also claim that their cartridge will work in old Mixet valves where the actual valve body is wearing away.

http://www.nomix.com/index.php