Testo 0563 9222 922 differential temperature set testo 0563 9222 p the testo 922 temperature measuring instrument is ideal for measuring differential temperature in the sanitary and hvac r sector the 2 channel temperature measuring instrument measures 2 temperatures in parallel and can determine the differential temperature in a matter of seconds once the measurement is complete you can safely store your equipment in the handy bag supplied p p the set also includes two surface temperat