Plumbing – this plumbing “temperature regulator” called, and how to adjust it

hot-waterplumbing

I was told the below restricts/governs how much hot water can make it to my tub/shower. I'd like to know what it's called, and how I can adjust it to get hotter water.

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I'm attempting to twist the "cap" (the beige-ish color) to the right, but am meeting more resistance than I would have expected (having no knowledge of how it works). I'm afraid to attempt to turn too hard for fear that it is not what I'm supposed to adjust, and I could break/crack the pipe.

Or do I need to find an alan wrench or similar to adjust just the little silver deal at the top?

Best Answer

Thermostatic Mixing Valve

According to the installation instructions (PDF)

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  1. Let the water flow for at least two minutes to allow supply temperature to stabilize.
  2. Calibrate the mixed water outlet temperature by placing a thermometer in the mixed water stream.
  3. To adjust the setting of the valve, loosen locking cap screw with hex wrench, see Figure 4. Cap must be lifted 1/4" to adjust temperature. To increase the temperature, turn counter clockwise. To decrease temperature turn clockwise.
  4. Lower handle and tighten screw.
  5. Check outlet temperature.