I ran into a r12 walk in freezer. Box normally at 0 degrees f but it was at 20 degrees. Sight glass wasnt full so i evactuated recovered exc. I recharged with mp66 to full sight glass. Condenser is clean, evaporator is clean, fan is good. Ive got a 6 degree temp change at the evap. Line temperature at the txv bulb is 22 degrees. Line temp at the suction service valve is 32 degrees. Suction pressure is 15 pounds. High side pressure is 148 with a 94 degree line at the reciever. The lowest ive been able to get this thing is around 20 box temp and i was there all dam day but they periodicly did have to go in the box for product. There isnt much of a load in the box and whats in there is still frozen. This is a 4 by 4 box with about 8 foot eight foot ceiling height. Hvac sure is a heap easiar than the refer stuff. The temp does barely creep downward but i mean it does it slowlyyyy. This is a chinese restrant and i think the owner is getting ansy..im faily positive i saw him polishing one on those samarai swords like john belushi use to swing on snl.