Quote Originally Posted by TF12 View Post
Hey,
Got some basic questions about ammonia and how it differs from halocarbon refrigerant systems. I'm well aware of the toxicity and trapping of liquid ammonia between valves. I've been to 2 four day training courses strictly for ammonia use, but some questions linger.
For example if you need to isolate part of an ammonia chiller for repair lets say the compressor package. Do you can you just vent the ammonia? If so what are the best practices involved? Is there recovery equipment for industrial purposes or is that a waste of money? On a basic ammonia chiller like a Vilter with a thermo syphon evaporator setup and the levels in the evap are too high... Can you drain the ammonia by gravity or is that possible? If oil from the separator gets lost out in the chiller, will it come back with run time or does if have to be drained?
I have lots of exposure to industrial chillers using R-22, 123, 507, 404a etc.
I know 717 deserves respect
Any help appreciated.
Venting a compressor depends on local laws, you can vent to air, in water,or use transfer unit. Some plants may have compressors running at lower pressure or vacuum. You could connect a suitable hose to transfer to the lower pressure.
If you do a lot of it, a transfer unit is not a waste of money.

Draining a surge drum by gravity can only happen if where you are draining to is equal or lower pressure, possible but unlikely.
Usually first close liquid make up to surge drum, then limit compressor capacity & very slowly reduce pressure, also restrict compressor suction stop valve.
If you have a suction trap or slop pot you may no need to restrict suction on compressor, but definitely find out reason for it, like leaking LLSV etc.

Oil does not return, you have to drain it from all low points at regular intervals like monthly etc