ComfortVu™ BACnet Thermostat Model Standard TB-HM (Line voltage)Carrier Proprietary and Confidential CARRIER CORPORATION ©2020Installation and Operation Guide All rights reserved12Freeze ProtectionThe Freeze protection feature will not allow the room temperature to dropbelow predefined cut-in temperature. Depending on which configuration thesystem is operating under (W/WO Heat pump), this feature will force thesystem to operate in heat mode and activate the fan.This feature will take effect when the thermostat is either ON or OFF. Whenthe room temperature rises above the predefined cut-out temperature, thethermostat will return to its previous state.When freeze protection is activated, the display alternates between “AL”and room temperature.EconomizerEconomizer is used to reduce the energy consumed by the cooling systems, by using low external air temperatures to assistin the chilling process. When outdoor temperatures are lower relative to indoor (room) temperatures, the system utilizes thecool outdoor air as a free cooling source.The outdoor temperature (Teconomizer) triggering the activation of the economizer, can be measured by the temperaturesensor connected to T1,0 terminals (technician parameter P08="05") or by setting a temperature value manually throughcommunication - AV#129 "TEconomizerEffective".When getting the temperature through communication, terminals T1,0 can be used for any other functionality like Externalsensor/Soft start in heat sensor/De-icing in cool/Door switch/Key tag.Whenever there is demand for cooling and the outdoor temperature conditions allow the operation of the economizer, it willoperate together with the regular cooling system and will not replace it.Economizer will start when, and run as long as, both of the following conditions are satisfied:1 Teconomizer temperature < Room temperature - (Cool differential band / 2)2 Room Temperature > Setpoint temperature
