Fox_FT3_-Approvals_Cal-VaZero CAL-CHECK™ is a companion test to the CAL-V™ Calibration Validation feature available on the Fox Model FT3 Thermal Mass Flow Meter & Temperature Transmitter. Where CAL-V tests the functionality of the sensor and its associated signal processing circuitry, Zero CALCHECK checks for build-up on the sensor that could affect calibration; further validates the zero stability of the meter; and checks thermal conductivity (heat transfer) repeatability of the sensor. Unlike CAL-V, which may be performed in the pipe and at process conditions, Zero CAL-CHECK must be performed at zero flow to ensure a valid test result. Depending upon the configuration — in situ or out of pipe — zero flow will either be compared to a customer- established field baseline or a factory baseline.