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Pressure Balance Shower Valve

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A Moen pressure balance shower valve
Aaron Stickley
Have you ever been in the shower and suddenly the water gets super hot or super cold? The sudden temperature change is due to a drop in either the hot or cold side water pressure. This can happen when someone else in the house turns on the water at a fixture, when the washing machine fills, or even when the dishwasher begins part of the cycle that uses more water. This is where a pressure balance shower valve comes in.

A pressure balance shower valve can provide even temperature to a tub or shower valve despite fluctuations that may occur from other water usage in the home, condo, or apartment. Having a pressure balance valve is even more important if you live in an apartment or condo where water is shared by several units.

Shower valves that are not pressure balanced can be dangerous, especially for homes with little ones, due to the threat of scalding water. In most building codes pressure balance valves are now required but if your home or apartment is older it may be time to install a new shower valve to make the shower safer and more comfortable.

The way that a pressure balance shower valve works is by maintaining a balanced outlet of water from the hot and cold side. The valve has either a balancing spool or a diaphragm inside the valve body that reacts to drops in the pressure of one incoming water supply (either hot or cold) and adjusts the outflow of the opposite water supply so that the water doesn’t get any colder or hotter. Sudden changes in supply water pressure may reduce the outflow of water from the showerhead but it will not change the temperature.

Pressure balanced shower or tub and shower valves can come in single, double, or three handle varieties so you can usually match the existing holes in the tile or surround when replacing an existing valve. The conversion to a pressure balance valve may require some changes in the hot and cold water supply and the shower standpipe in the wall to allow the new valve to fit. If you are not comfortable working with water supply pipes in the wall you may want to hire a plumber to replace the valve.

The cartridges in pressure balanced shower valves can and will go bad eventually. When a cartridge goes bad it may not mix the water evenly and you might be getting mostly hot or mostly cold water. It may also not get hardly any water at all. These are all signs that the cartridge may need to be changed to a new one. Once a new cartridge is installed in a pressure balanced shower valve it should work like new. Extend the life of the shower valve by turning it on regularly even if that bathroom does not get any use. A valve that sits without use for too long is more likely to go bad that one that is used often.

Note: If you are installing a new pressure balanced shower valve it is a good idea to save the paperwork because it will make it easier to identify which replacement cartridge is need when the time comes to change it. Also, sometimes a simple call to the manufacturer will result in a free new cartridge so keep the phone number handy.

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