Daikin U0 error code: refrigerant shortage on a mini-split

What Does Error U0 Mean?

Daikin assigns U0 to a refrigerant shortage. The control has seen the circuit behaving as though there is too little refrigerant, from readings such as a low suction temperature or an abnormal discharge condition. A closed service valve, an undercharge left after install, or a leak all present as U0. Applies to: Daikin room air conditioner splits and multi-split systems that publish U0 in the malfunction code table This meaning follows the Daikin malfunction code table for room air conditioner and multi-split systems that list U0. SkyAir, VRV, and Altherma ranges use their own code sets, so confirm the indoor and outdoor model numbers before applying this page. Owner-safe checks: Note whether the system is newly installed or has a long service history, and whether output faded gradually or stopped suddenly before U0. | Check from the ground for oily residue at pipe joints or unusual frosting on the outdoor unit, without touching the pipework or valves. Qualified technician: Refrigerant-circuit diagnosis and charging require a qualified technician with the applicable refrigerant handling credential.