Unfortunately, what was lost when the options and features were condensed were some of the diagnostic tools and control features. The NU-4750 is the base model with temperature and CO2 display and control features. On all of these units, temperature, CO2, O2 and RH calibrations are performed in run mode at the operator panel. That's right, no more pots to adjust, no panels to remove, and no access doors. All calibrations and configuration changes are performed at the front control panel.
Service personnel can manually test functional components.
This additional procedure needs to be performed at installation and any time the CO2 tank pressure is altered. The purpose of this calibration is to teach the unit how long it must inject CO2 after a door opening. Once calibrated, the unit will precisely inject enough CO2 to recover, quickly, without overshooting. Training is available on this and all NuAire products.