Freezer Compressor needs a CPR valve?

[Newsurvey6]

I have been working on a reach in freezer on a that has a MOP expansion valve. I am have trouble with the compressor starting and staying online when coming out of defrost. My thought is it needs a CPR valve, but I know you can't have both devices on the same unit. The expansion valve has been recently changed so I think is doing what it is designed to do. Would it be advisable to change to a regular expansion valve and add a CPR valve?

[Magoo]

If MOP TXV has been changed recently check selection, as they have a couple of control ranges, check that you have the low temp application range.

[mbc]

after you checked what magoo said .
has compressor have unloading systems or not if yes check that system .
also you can give time between defrost and ran time in compressor with running fans (some digital a defrost timers has got this option) 3 - 4 minutes is enough , in this time evaporator temperature comes down after defrost ( so our suction pressure comes down)

[mikeref]

"Reach in" freezer so it will be a sealed unit. Evap fans should not start straight after defrost.( As mbc has said)
Coil has to chill down first. Check your run capacitor. MOP 45 or 60?

[Sandro Baptista]

"MOP 45 or 60?"

It should be, even for ºF, much lower...