If we were to shut off both compressors with the 508B side very hot there is a very high chance it will blow the plug or a seal. Not sure if the shell and tube or the flex line is the weaker point.

R507 compressor is plugged into battery backup and R508B is connected to non-backup power. Both are on the same switch. When power is cut one compressor is made to stay on.

The shell and tube condensor will remain down at -40 ~-50 (max capacity) and keep the 508B compressed long enough for the compressor to cool down to a stable temp.

I will get another pic with the UPS isntalled and the head frozen over. we seperated the hot plate and reconnected the power to the fan seen in pic 2 face up w/blade off. We stole the power for the hot plate to load test.

We never let the 508B out, I only have 4 pounds left.