Carrier Chillers (5H120) Comp.

Shogun good job.

Yes the nominal tonnage is 120 usually with a 125 hp open drive running the tonnage to 123 fully loaded. Uloaded 60 tons.

The 120 is the short stroke comp usually installed in multi evaps DX systems with small RA shafts. The 126 is long stroke and it nominal tonnage 132 tons used in class a1 style of buildings, that have large RA plenums and usually one large DX coil with multiple passes.

The capicity controller is located in the front of the compressor by the oil pump housing. If you have oil problems be sure to check the oil regulator, they always seem to get plugged up reducing the pressure to unloaders and increasing it to the journals and running higher amps from the journal load.

When you set the unloaders do not just use an amp meter use your gauges as well. The compressor should begin to unload at 58 pounds. If you run it lower you will loose efficencicy in the evaporators and tend to slug or ice. 58 pounds should also bring on HG if it is present.

General rule of thumb for unloaders is 58 to 75-78. After that you will need to begin to load again so that you do not loose effiencify at the high end.

I took over the service work 2 years ago and accorrding to the service records the annual service has been kept up and they are used regulaly during cooling season. What are some symptoms I can look for that will tell me that it might be time for an O-ring and/or unloader replacement. By the way thanks for both answers, they will deffinately help me with PM and CM.

edit

Please excuse me as I made a major mistake with regards to "O" rimgs on the Carrier 5H120. It doesn't have "O" rings ...I was thinking of the Trane "B" compressor so no need to worry about it. The Charier 5H 120 has unloader power elements with unloader forks that lift an unloader sleeve which lift the pins to lift the suction valves off the seat. I have never had to repair one. Again Please accept my apologies. If I were you I would try to get ahold of a Manual on the 5 H series.

Roger

The next time you go into an EBward, Valair, United tech, Store go to the literature rack and get the free manual for the 5H120 Comps. They used to give them away when I was wrenching back in the late 80's. The manual is just the Service manual, but it has all the specs you require.

Thanks for the information, do they have a web site?

No problem, I got alot out of your answer. it sounds like you know your chillers. Thanks again.