There are gamblers out there who will bet on almost anything, cards, horses, dogs, you name it. But so far, we’ve never heard of a bookmaker giving odds on the safety of the water supply in a commercial domestic hot water system. Some property managers, on the other hand, either deliberately or inadvertently, are all in on that bet. They are betting that they can save a little money by not installing a 3-way domestic tempering valve, and still deliver hot water at the right temperature that is bacteria-free. They seem to gladly take that bet if it saves them some money in the short term. Unfortunately, if the bet goes bad, they stand to lose a lot more than if they had invested in a 3-way domestic tempering valve.
Here is the bet that some property managers take.
Most local and national plumbing codes require that the maximum temperature delivered to the hot water tap cannot exceed 120° F. This safety rule is in place because a water temperature of 125°F can scald an adult within 3 minutes and a temperature above 130°F can scald in seconds. Children and the elderly are even more at risk.
Instead of installing an Electronic Tempering Valve (ETV) like the Heat-Timer® ETV Platinum Plus to precisely control the temperature going to the faucets and showers, a property manager will just set the hot water heater/tank thermostat to 120°F and gamble that will be good enough.
A Risky Bet
Keeping the domestic hot water at 120° F is a risky bet because the temperature growth range for Legionella bacteria, the bacteria that causes Legionnaires disease, is between 68–122°F. Between 122°F and about 130°F the bacteria can survive but not multiply. If the hot water heater/tank is set between 120°F and 125°F there is no place in the entire hot water system that is hot enough to kill the Legionella bacteria. That takes a temperature above 140°F.
Here is where the property manager rolls the dice. If the domestic hot water temperature is set between 120°F and 125°F they are betting that there is no Legionella in the hot water system. Because once the bacteria is in the system, it won’t leave. Even in a circulating hot water loop, there are sections near the end of the loop that can drop below 120°F during periods of low usage. In those cool sections of the system Legionella can multiply. Once that water gets back to the water heater, it will be too hot for the bacteria to multiply, but not hot enough for it to die. The bacteria are ultimately pulled back into the circulation loop where they again have a chance to multiply.
Maintaining a safe DHW system doesn’t have to be a gamble
There is a better way to protect hot water users from both dangerous water temps and the risk of Legionella inside the hot water system. First the tempering valves like Heat-Timer’s ETV can maintain a steady temperature of 120 +/- 2 degrees in the loop, preventing temperature swings in the facility, even under rapidly changing flow conditions, thus reducing the potential scald hazard.
Second, using an ETV allows the hot water temperature to be stored above 140°F, ensuring that any Legionella is not just rendered inert, but it is actually killed. The high temperature in the water heater/tank means that no live Legionella enters the circulation loop, meaning that it cannot populate the sections of the loop that may drop below 120°F. Any bacteria that is either in the loop or entering in the make-up water is returned to the water heater/tank where it is killed by the high water temperature.
With a Heat-Timer® ETV building occupants are winners too.
For the occupants of the building, the benefit of having an ETV tempering valve is obvious during high demand periods.Water usage in the systems without an ETV and 120°F storage temperature will begin to pull down the temperature in the water heater/tank as cold makeup water is introduced. This demand outstrips the ability of the water heater/tank to heat the incoming water. Resulting in just lukewarm water at the showerhead.
With an ETV installed in the system, a drop of a few degrees in the water heater down from 140°F will not affect the water temperature at the showerhead. This is because the ETV Platinum Plus controller will maintain a steady 120°F temperature in the hot water loop, even during peak demand in the morning. At the showerhead, the water temperature stays just right.
With a Heat-Timer® ETV Platinum Plus you get safe hot water and BuildingNet too.
Investing in a Heat-Timer® ETV will ensure that the hot water system is safe for users and stays safe. For the property manager, the ETVPlatinum Plus interfaces with BuildingNet, Heat-Timer’s remote access software, like all Heat-Timer® Platinum products. BuildingNet allows you to monitor the performance and see alarms from the DHW controller on a mobile device anywhere with internet connection, whether on vacation at the casino or at home in a nice hot bath.
With the Heat-Timer® ETV, you’ve made a winning bet every time! To learn more about safe domestic hot water solutions, contact us today or visit our website at: https://www.heat-timer.com/