Thermostatic and Pressure Balanced Valves
Thermostatic and pressure balanced mixing valves help to further regulate water temperatures in placed like the bathroom shower. These valves mix hot and cold water to ensure a near constant temperature and pressure of the water output from the fixture. Fluctuation from variations in both the temperature and pressure of the incoming water supplies is mediated by these devices.
Pressure Balanced Mixing Valve
A pressure balance shower valve addresses temperature flux only due to inlet pressure changes. The internal mechanism is designed to maintain water temperature despite pressure fluctuations in the hot andr cold supply. As an example, when someone flushes the toilet it will not cause the water temperature in the shower to suddenly get too hot. The pressure balance valve does not sense the actual temperature of the water, just the ratio of hot and cold water supplied to the valve.
Thermostatic Mixing Valve
A thermostatic control valve prevents high output temperature regardless of input and outlet variations and demand variations.
Criticism
These devices are not without their pitfalls. One major concern is the increase in overall expense to the homeowner. There are many homes where the hot water heater temperature is not set high enough to cause dangerous scalding. It is not necessary to have a hot water heater with a setting above 120 degrees, and it is actually quite sensible to have it set at 110 degrees. This saves the homeowner money.
The most common regulatory standard for the maximum temperature of water delivered by residential water heaters to the tap is 120 degrees Fahrenheit/48 degrees Celsius. At this temperature, the skin of adults requires an average of five minutes of exposure for a full thickness burn to occur. Most adults will suffer third-degree burns if exposed to 150 degree water for two seconds. If a homeowner has a commonsense temperature setting on the hot water heater, then a special mixing valve is not necessary at the hot water heater or shower. Keep it turned down, you don't need the water near boiling when it comes out of the tap!
Another problem with the mixing valves is an increased failure rate due to impurities in many urban or rural water systems. High calcium content in water causes the moving mechanism in the pressure balance mixing system to fail, leaving the homeowner without water pressure in the shower or other fixture. Frequent disassembly, cleaning, and possible replacement is necessary in some areas where hard water is unavoidable. Some homeowners have had to install a home water softener or filtration system to help reduce failure of these mixing valves.
- Increased fixture cost
- Higher failure rate
- Other added expenses such as a water softener
This is another example where the government wants to be our parent in a nanny state nation. The intelligent homeowner is not going to become injured by scalding if commonsense is used. However, because some dumb citizens might get hurt, the government is going to step in and force everyone by building code to update to more expensive bathroom fixtures or water heater safety devices and make us all pay more as well as over-complicate something that is frustrating enough, home plumbing.
