we had a liebert unit about 12 yrs ago with 3 low charge calls in a week. could not find the leak. finally i was there and the condenser fan cut off (bad motor) and there was a relief valve that opened and shot r22 for about a minute. only one i ever saw.
am very familiar with internal relief, i just was hopin' to start the cool quiz with a 3 this week!
In the land of the blind the one eyed man is King! semper fi
Ive seen a pool dehumidifier with an external relief on the reciever back when I first got in the biz, the boss bypassed the hp switch trying to troubleshoot, nice fog show out of the ducts for all the swimmers lol