Quote Originally Posted by bruisermac View Post
hey M L CA ... sounds like you need to wire your condenser fan to run all the time. that should be fine with R404a as you needed the cycling action with R134a to keep the head pressure up in cold ambients.

the reason its tripping is cause it wants to pump down on defrost but because the fan is off it builds head and trips fast even before it can shut off. you may have a problem with the cycle switch as it should cut in on a rise in pressure. i have seen before that the compressor contactors stick and work erratically at best. we always lube those contactors.
Or it may possibly be overcharged with refrigerant.