It’s a common issue, especially with older residential buildings. A toilet flushes and the water pressure in the sink drops, or the shower turns scalding for a few seconds before stabilizing.
In a single-family home, it’s an inconvenience, probably written off as a quirk of the building. In a multi-family home, apartment building, bed and breakfast, hotel, or other commercial application, however, it’s a major problem, particularly if plumbing is interconnected. No one wants their shower to turn scalding because the person in the next unit flushed the toilet.
The Likely Culprit: Pressure Balance Valves
Pressure balance valves are a type of anti-scald valve installed in sinks and showers as a safety measure. They allow for a maximum ratio of hot to cold water in order to prevent scalding. However, pressure balance valves are only able to control the ratio of hot to cold water; they’re not actually able to control the temperature.
When a toilet is flushed, cold water rushes in to fill the tank, leaving a dearth of cold water throughout the rest of the plumbing system. If the shower is running, there won’t be any cold water to mix with the hot water, so the shower will only receive hot water and/or lose pressure until the toilet flush cycle is complete and cold water is available again.
This has drawbacks not only for comfort but for safety as well. Children and elders have thinner skin—while 120° F is recommended as a general maximum temperature, a safe bathing temperature for babies and elders is closer to 100° F.
The Solution: Thermostatic Mixing Valves
Unlike pressure balance valves, thermostatic mixing valves (commonly called thermostatic control valves, tempering valves, or simply mixing valves) feature integrated thermostats, so they are able to target a particular temperature. If it detects a lack of cold water due to demand somewhere else in the system, it will temporarily decrease the amount of hot water to maintain a steady and safe temperature.
Safety Benefits of Thermostatic Mixing Valves
Thermostatic Mixing Valves as Anti-Scald Devices
With the ability to set the temperature at a specific number, you can be sure that it will never reach a dangerous temperature. Because it’s customizable, it can be tailored—in a house with young children or an assisted living facility, the temperature could be set at 110 or even 105° F, while 120° F might be perfect in a hospitality application where it will be used by a wide range of people with a wide range of preferences. In these circumstances, comfort is accommodated, and safety is ensured.
Thermostatic Mixing Valves for Legionella Prevention
Legionella is a dangerous germ that lives in warm water. It can cause Legionnaires’ disease, a severe type of pneumonia, or Pontiac fever. Without proper prevention, Legionella can easily grow in many common sources, such as hot water tanks and heaters, large plumbing systems, hot tubs, and more.
Legionella grows best within water between 77 and 108° F — around the same temperature that is recommended for bathing. To kill off this dangerous germ, it is recommended that water be maintained (PDF) at 140° F, high enough to prevent it from growing and spreading.
This temperature is much too high to safely bathe in, however. With a thermostatic mixing valve, the maximum temperature could be set between 110 and 120° F, while the water heater can be maintained at 140° F. The hot water will remain at a safe temperature, while the mixing valve will ensure that it is always tempered with an appropriate amount of cold water to maintain a safe temperature.
Additional Benefits of Thermostatic Mixing Valves
Acorn Controls® thermostatic mixing valves save water when compared to pressure balancing valves. They are designed to draw hot water until cold water is required to meet the correct temperature; then, they draw only as much cold water as necessary. A pressure balancing valve will draw from both hot and cold water supplies; as a result, there is no limitation on the amount of cold water they will draw, and they waste water as they take longer to reach the appropriate temperature.
Greater water efficiency and lower water wastage means lower costs—from the outset and over time. Additionally, Acorn offers combination, or dual-certified valves—valves that combine a thermostatic and pressure control mechanism. Traditionally, these combination valves were expensive, as they combined two mechanisms in one.
Acorn Controls thermostatic mixing valves accomplish both jobs with just one sensor, enabling us to lower production costs and pass those savings on to you.
Acorn offers shower mixing valves that meet a wide range of certifications, including:
- ASSE 1016
- ASSE 1017
- ASSE 1069
- ASSE 1070
- ASSE 1071
Many valves are certified to multiple ASSE standards. In addition, Acorn valves comply with CUPC, NSF/ANSI 61, CSA B125.3, and/or Lead-Free standards.*
Thermostatic mixing valves offer a more elegant solution to water safety than pressure control valves. Water fixtures that use thermostatic valves are more reliable in temperature than those that rely on pressure control valves, and thermostatic control valves provide more granular control over the temperature for safety and pleasure.
Acorn Controls offers a wide range of thermostatic mixing valves for all manner of applications from residential to commercial, hospitality, and everywhere in between. Explore our valves here, and get in touch to request a quote or place an order.
*Note: Valves may comply with some, all, or none of the listed standards. Check the product details and/or submittal for a specified product to see its certifications.