Ok guys. I'm training / evaluating a new coworker who has more experience than me (I have about 3-4 years only). Our company does restaurant refrigeration - in other words, small reach-ins, walk-ins, and ice machines. HIS experience is primarily supermarket refrigeration and large air conditioning.
Some of the things he says seem wrong, but he says that's how it is on big equipment. It doesn't make sense to me. Here it is:
1. "Restricted drier will be very hot" I said no, a restriction in liquid line will have a temperature drop if anything. He says not on big AC units. He says the compressor is so big it pushes past the restriction and gets hot?
2. "Low on charge will cause high suction and sometimes very high head, but only if a little low, not very low. Add refrigerant, and suction will drop and head will drop." I said totally backwards dude, flashing before TXV causes low suction. He says no, flashing due to low on charge causes the TXV to open up wide due to warm evaporator causing high suction. ??? I've never seen that, he said even ice machines will do it?
Regarding high head due to low on refrigerant, I said maybe headmaster is bypassing due to low charge? He said no, this is how large AC units with no head pressure control work.
If he's right I want to know, because I always thought refrigeration principles work the same regardless of application. He has about 8-9 years more experience than me, and I've never worked on a supermarket rack, and I've never worked on an AC unit other than a couple of residential ones for family members.
What say you?