Honeywell Home EW500 energy calculators are used for energy consumption metering in hydronic heating and cooling systems.

They are typically combined with a pair of temperature sensors and a mechanical or ultrasonic flow sensor, for example Honeywell Home EW370 or EW480 Series, to provide the full functionality of a heat meter. EW500 energy calculators are suitable for energy metering of heating energy, cooling energy or heating and cooling energy transported in one pipeline. The switch between heating and cooling register happens automatically when the t turns negative and the supply temperature falls below the programmed threshold. Metered values, error logs and configuration changes are stored in a non volatile memory. The calculator can be read out over the display or remotely. For local readout the meter is equipped with a multiple line 8+4 digit LCD display. For remote readout the EW500 offers a variety of retrofittable interface modules, including M-Bus and Modbus. The calculators standard configuration can be modified by using a PC software and connecting over the ZVEI standard optical interface on the front of the device with optical interface EWA3001798. A separate permission level is available for user and legalisation access to avoid unauthorised tampering with approval relevant configuration items. Temperature sensors are not supplied with the calculator and have to be ordered separately. Standard configuration is prepared for 2-wire Pt500 temperature sensors. A model is available for 4-wire Pt100 temperature sensors. The housing is closed with two sealable screws. It has protection class IP54 as standard. EW500 energy calculators are supplied with a backplate for mounting to a wall.