Hansgrohe Thermostatic Shower Cartridge

[Kiko]

My parents have a hansgrohe shower that takes a thermostatic cartridge (part #94282000).

The cartridge is not leaking, but when you first turn on the water, it comes out scalding hot for a few seconds. Then the water becomes luke warm and it stays luke warm, regardless of where you position the temperature controller on the handle. Also, the temperature controller turns much further to the left (hot) than to the right (cold), where it used to turn equally far in both directions from the center position.

I called the HG customer service number, and the tech said cleaning the filters on the cartridge might help. Does anyone have experience with thermostatic cartridges? Is there some kind of thermostatic control that could be adjusted or is it all in a sealed unit? Should I soak the handle and cartridge in white vinegar to try to clean the mineral deposits or just go ahead and replace the cartridge?

 

[Jadnashua]

Many of them have a calibration adjustment, but I doubt that's your problem. There are a couple of ways (that I know of) that these things work: a bimetalic control or a wax filled chamber. They both respond to temperature changes and rely on relative motion to move the valve to control the temp. When you bond two different metals together, since they do not expand at the same rate, the stuff will bend, which can then adjust the temp - same idea as a mechanical (often a dial type) thermometer. On a wax cartridge, the volume changes with temp changes which can push/pull the valve to adjust the temp. Don't know which Hansgrohe uses, but it sounds like the 'linkage' is broken and it is no longer able to adjust properly. I doubt you'll be able to fix it, and will need to replace it.

Somebody that deals with the things more may have some better advice. If there is crud caught in there, that could inhibit the mechanism from moving, but it might also cause it to deform and break. If you're lucky, cleaning may resolve the problem.

 

[Sponsor]

 

[Kiko]

Thanks, Jim.

I'm hesitant to change it out for two reasons:

1. I've never had to replace a cartridge before that wasn't leaking.
2. If the problem is just due to a build-up of mineral deposits in the handle, etc., then I could have the same problem with the new cartridge.

 

[EuroPlumber]

Thermostatic cartridge 94282000 has filter screens on it. They need to be serviced before deciding if you will need to replace it. When a thermostatic valve starts to behave irraticaly, 95% of the time it is due to the filters becoming plugged up with debris. You need to pull the thermostatic cartridge, clean the filters, then calibrate the sleeve and handle, to get the proper temperature range.

 

[Kiko]

Thanks EuroPlumber!

Can you give me instructions on how to calibrate the sleeve and handle?