1. calibrate 1mA trough RTD
instead of sensor, just push your ampermeter in the PTC slots of the board, turn the board on and set CAL1 pot so that you can see 1mA going trough ampermeter.
2. calibrate PTC amplifier gain (to =30)
instead of sensor, attach a 100R 1% (or better) resistor to the PTC connector
remove jumper from JP1
measure voltage on the top pin and turn RV2 until you get 3.00V exactly