A tempering valve mixes hot and cold water to create water at the perfect temperature to distribute to sinks and showers. They are typically used in hotels or office buildings, anywhere where there is centralized delivery of hot water. If the water delivered is too warm, scalding can occur. If stored water is too cold, bacterial growth can occur inside the tank. The tempering valve allows hot water to be stored at a high temperature that will kill off bacteria, but then mixes it with cold water to distribute to the fixtures at a lower temperature that will not scald users.
Temperature ranges for domestic hot water systems
If water is stored below 140℉, bacterial growth can occur that can have serious health risks to building occupants. The most common bacteria is Legionella, which has been known to grow in domestic hot water systems, as well as cooling tower water. In order to kill off any existing bacteria and discourage new growth, water must be stored above 140℉ often as high as 160F. For domestic hot water systems this means that the storage tank must be maintained at or above this temperature. However, scalding will certainly occur if water that hot is piped directly to a sink or shower. Depending on local code hot water to fixtures should be in the range of 115-122℉. The tempering valve is installed at the outlet of the hot water storage tank, and its output is then piped out to the hot water distribution of the facility.
How a tempering valve works
There are several types of tempering valves in use today. They are all 3-way valves, meaning that they have two inputs (hot and cold water) and one output (tempered hot water). They are named based upon the type of control used to maintain the tempered hot water temperature.
A thermostatic mixing valve (TMV) has a fixed set-point and precise water temperature control. The controls are mechanical, and all internal to the compact valve, which is simple to install but because it operates only from a single set-point, lacks the ability to self adjust in certain DHW configurations.
An electronic tempering valve gives operators more flexibility by being able to adjust the set-point, monitor performance remotely, and access information on a control screen mounted away from the actual valve. These are good choices when more active monitoring of the water temperature may be required.
An example of a robust electronic tempering valve is our Heat-Timer® ETV Platinum Plus Control which can be located up to 500’ away from included control panel. This panel can communicate to larger EMS or BMS systems in the building and perfectly controls the flow of hot water through our motorized 3 way tempering valve.
Typical thermostatic and electronic valves need to be installed into the piping system by the contractor, and often require many field connections and thermostats to be hooked up correctly in order for the system to function correctly. Electronic tempering stations are a pre-plumbed unit that only need to be hooked up to hot and cold water and power, avoiding manual connection of the valve and the sensors in the field. This saves installation time and provides a more robust installation. For more information see our product page on the Electronic Tempering Station (ETS).
Plumbing Professionals Trust Heat-Timer® Valves
Heat-Timer® is dedicated to providing the highest quality domestic hot water valves on the market. Our team of technical experts can help you pick out the right valve for the job, be it a school, retail center or resort. You can rest easy knowing your systems are being reliably controlled for occupant safety and energy savings as well.
Contact us today and speak to a technician or visit our website at https://www.heat-timer.com.