Chiller guys and gals
This is one that has been going on for a little while....McQuay R134a machine, Model# PEH087-AAAB
Serial number S7B81030-00. About 2 or so years ago, the shop got a call on this machine. A tech went out, L1 and L2 600 amp fuses blown. Replaced. Ran for a couple of months. Another tech goes out, L1 and L2 fuses blown. Replaced. This happened a couple more times and I inherited the issue. I cannot say what they found and they have long since left the shop. So, around Nov of 2003, I get my first call on this machine, and by now, I am sure that you have guessed the call.... thats right, L1 and L2 fuses blown. I meggered the motor to ground, showing at or close to infinity,with no phase to phase shorts, checked wires and physical interlock, etc. I did decide to order and change the shorting contactor points, and ran the machine.Didn't have a problem with this machine(that I know of) until recently, when maintenance was being done on the tower and I caught hell trying to get it online with very cold tower water. I made a point to ask the facilities director if the fuses had blown since that last call and he indicated that they had not had a recurrance of this issue....until this morning. So, I get there and L1 and L2 are blown, megger as stated above and check the physical interlock between 1S and 2M, as I did before. I am going to replace it and the other AUX contactors in the course of my trouble shooting and would like some input. Thanks.