Typical Chiltrix air to water heat pump used with domestic water heating design. Only major components are shown.

Legionella Danger Zone (and Safe Zone)

• Above 70 °C (158 °F) – Legionella dies almost instantly

• At 60 °C (140 °F) – 90% die in 2 minutes (Decimal reduction time (D) = 2 minutes)

• At 50 °C (122 °F) – 90% die in 80–124 minutes, depending on strain (D = 80–124 minutes)

• 48 to 50 °C (118 to 122 °F) – can survive but do not multiply

• 32 to 42 °C (90 to 108 °F) – ideal growth range

Minimum requirements For Chiltrix automatic anti-legionella function:

*  Follow the applicable sections of Chiltrix CX34 Manual and DHW Tank Manual.

*  A 40a contactor as described in the CX34 manual must be installed on the power circuit to the thermostat.

* A commercial grade thermostat capable of a 170F set point must be installed along with the heating element.

* An anti-scald valve must be employed immediately after the tank hot water outlet, per local code, to prevent      dangerously hot water from causing injury or death to a person. Water at 160F can be very dangerous.

* Expansion tank and/or pressure relief valve must be installed per local code.

* Use only a UL listed thermostat and element.

* All wiring must be performed per local code.

* Set the parameters in the Chiltrix controller up as desired and per instructions in the CX34 Manual, and enable.

Note – When using the anti-legionella function along with DHW domestic water heating backup heat (for times when the heat pump/coil cannot meet the load) the heating element is fully managed by the Chiltrix controller. The thermostat is generally not active and serves as an inline safety feature to prevent overheating of the tank in case of relay or sensor failure, etc. In this example Chiltrix controls all water heating functions.