Refrigerant R1234YF Water Content

Only very small amounts of water are soluble in liquid refrigerant. On the other hand, refrigerant vapor and water vapor mix in any ratio.
Any water in the refrigerant circuit will be entrained in droplet form once the dryer in the receiver or reservoir is saturated (absorbed approximately 7g of (0.25 oz) water). This water flows up to the expansion valve nozzle or restrictor and turns to ice, and the A/C system no longer has a cooling effect.
If the water present on the A/C compressor regulator valve turns to ice, it can lead to different complaints depending on the design of the A/C compressor (either the A/C system does not cool or it cools so strongly that the evaporator ices up).
Water destroys the A/C system, because it can form acids when combined with other contaminants at high pressures and temperatures.