Was on vacation last week and got a panic call from work yesterday that the entire building had no A/C. The electrical contractor that was suposed to swap in the new service on Monday (when I would be there) did it on friday because thats when the utility co. was avaiable.
I had 1 of the maintenance guys check all the units for air flow by feeling the registers, he reported no or very little air flow. I told him to shut then all down as the it looks like the phase rotation to the entire building has been reversed.
The units are as follows
2 5 ton York packaged units (recip compressor)
1 8 ton York packaged unit (recip compressor)
1 Trane 14 ton packaged unit (with replacment copeland scroll compressors)
1 3 ton split (recip compressor)
1 1/2 horse copeland refrigeration split (recip compressor)
These units had run about 5 hours with reverse rotation. I had him swap 2 leads on the disconnect on the Trane and start it back up so the main area would have cooling, he said it's worling fine. Guess the scrolls lived.
Now the question that I am going to answer at a meeting on Tuesday, has anything been damaged. I say this will have shortened the life of the compressors for the followng reasons.
1 the Yorks and the 3 ton split are 8 years old and the crank bearings have a wear patern in 1 direction. They now have 5 hours of run time in reverse, most likely sluging liquid the entire time because the evap air flow was non existant as the 3 phase fans where runing backwards. The condensor fans are single phase so they ran in the proper direction
2 the Tranes with the 6 month old Copeland scrolls do not pump while runing in reverse so they must have been cycling on internal overload due to over temprature of the motor. The 3 phase evap fan was runing backwards but since scrolls do not pump runing backwards no slugging
3 the copeland refrigeration (semi herm) is a 4 month old replacment compressor so I do not feel there is to much of a bearing wear patern there and it had normal air flow as the evap fan is single phase. I am not woried about this one
I also need to contact the Elevator company to ask if the hydralic pump can be damaged by reversing rotation, anyone know the answer to this one.
Opinions and addtions to my list please, I want to have all bases covered.