If you are planning on remodeling your bathroom with a designer or contractor, you may have been asked what kind of shower system you would like. There are only two basic systems, and chances are you've used both at the same time, but the engineering installation can be confusing.
Shower system for pressure compensation
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With a pressure balancing valve, you have a lever that works on / off and only controls the water temperature and not the water volume. When the valve is on, the valve is fully on .
You can't reduce the volume of water that comes out, but you can always use an adjustable shower head to change the pressure.
Thermostatic shower system
With a thermostat system, you usually have two levers or controls. One lever adjusts the water temperature (thermostatic valve) and the second lever regulates the water volume and the on / off function (volume control valve).
This system allows you to set the temperature once and for all so that it can be adjusted to your liking every time you shower. You can also adjust the water drain volume, but 2.0 gallons per minute is still the maximum. These valves are more complex and therefore more expensive than pressure equalization valves.