What is the acceptable level of water in oil sampled from Ammonia refrigeration compressor? We received results ranging between 0.1% to 0.3% (by Karl Fischer) without the oil turning turbid.

On ammonia systems I have seen that are running well, the level of moisture is normally less than 100 ppm (0.01%). There are a lot of oil samples that are less than 50 ppm.

The levels of water you have seem too high for comfort. If the iron and / or zinc numbers are elevated, I suggest you look for a water leak and dehydrate the system.

Thanks. The compressors in mind are Frick Screw units, about a year old. oil is Frick#10. we resampled the units and got similiar results.There is no dehydration device.No other irregular findings. At this moisture content, incomplete mositure purge during installation can be considered relevant?

Incomplete moisture purge is possible, but does not seem likely. There would have to have been a lot of water left in the system to get the moisture concentration up to 0.3%. Anyhdrous ammonia is typically less than 25 ppm moisture. You should be able to calculate how many pounds of water would have been left in the system after assembly based on the system charge and initial moisture levels in the refrigerant and lubricant.

You would know more about how the system was assembled and purged / evacuated than anyone on the internet.

When you say it has no other irregularities, that doesn't help too much. What you think is normal may not be what I would think is normal.