The Heart of any
Air conditioning or refrigeration system
is the Compressor.
Compressors usually work or they don't
with little in between
The compressors on a residential heat pump or air conditioner is usually hermetic that means the motor and the part that pumps is built into one box called a can.
The electric motor is installed in the can so the refrigerant flows over the motor windings to cool it as it runs. The insulation of the motor windings is like any electric motor that it is covered with varnish that doesn't react with the refrigerant unless it becomes acidic. Then the insulation gets eaten off the windings and the motor burns out. If you are lucky the circuit breaker or fuse will blow. If not then the motor will continue to run and ruin the refrigeration system. A system that is short of refrigerant (aka Freon) will overheat the motor a system that is overcharged can flood the compressor causing "liquid slugging". A bad crankcase heater will also cause damage due to liquid. This is not as much a problem on smaller systems but will destroy larger units. To learn more about the proper charge I have created this page.
When a hermetic compressor fails the only way to fix the system is to replace it. When it is replaced it is necessary to install filter dryers to clean up the system of moisture and acid.
The motor in a compressor if not 3 phase is usually a capacitor start capacitor run type. It will have a start capacitor and a run capacitor. If the run capacitor fails the motor will not start and draw excessive current than it should and over heat (tripping) it's internal protector (also known as an "overload"). If it doesn't have a start-capacitor it probably should. Especially if it has problems starting under load. If the cooling coil is replaced with one that has a thermostatic expansion valve as opposed to capillaries or an orifice. You may think that the compressor is bad because it won't start.
For more on this subject please visit the problem solving page and the cooling homepage.
The most common brands of compressor are Bristol, Tecumseh and Copeland. Other brands include Manurope, Trane, Danfoss, Aspera, Dunham Bush, Carlyle (Carrier) and York.
Picture of Carrier compressors in an old water cooled system. Note oil pressure safety controls and Ranco dual pressure control. To learn more about this system follow this link. The large device on the upper right is a suction line dryer used as a liquid line filter to get rid of crud in this system from past problems.
American Standard, Amana, Arco, Arco-Aire, Bryant, Carrier, Coleman Evcon, Comfortmaker, Day/Night/Payne, Dunham-Bush, Fedders, Fredrich, Goodman, General Electric, Hotpoint, Heil, Intertherm, Janitrol, Kenmore, Lennox (Armstrong, Johnson Air-Ease), Miller, Modine, Nordyne, Rheem/Ruud, Sears, Stewart Warner, Trane, Williams, White-Westinghouse, Whirlpool, Weil Mclain, York, (Frasier Johnson/Borg Warner) and others.
Written By: Scott Meenen
N3SJH of:
G&S MECHANICAL SERVICES.
Specializing in Mechanical, Controls
and Electrical Modifications Of
Heating, Air-conditioning, Refrigeration,
Cold storage,
Ice Production and Food preservation.
Anything having to do with Heat
and Energy.
Serving MD, DC, and Northern
VA.
Contact us by pager: 1-877-467-2914
.
Page
us by e-mail 4103560613.3732505@pagenet.net 240Chrs max.
Email us at: jsmeenen@toad.net