When multiple compressors are piped together with a common
suction and discharge header - such as with the arrangement of a parallel rack
configuration - oil return to each compressor is a major concern. Typical oil
recirculation rates are dependent on three factors.
Emerson Climate Technologies marked a milestone in
December 2010 when the 150,000th Copeland Scroll digital compressor was shipped
to the marine container industry. Emerson shipped its
first scroll digital compressor for refrigerated seagoing containers in 2002,
and now builds the compressors in two facilities worldwide.
Many servicemen experience service calls where the compressor has both a low head pressure and a high suction pressure. There are three main reasons why a reciprocating compressor will simultaneously have a low head pressure and a high suction pressure.
The compressor’s discharge temperature can tell the service technician what is going on inside a refrigeration or air conditioning system. The compressor’s discharge temperature is a reflection of the hottest part of a refrigeration system, and there are limits as to how hot a discharge temperature should be. This article will explore discharge temperatures and their limits.
The compressor's discharge temperature is often an overlooked temperature when troubleshooting a refrigeration or A/C system. However, it's very important because it's an indication of the amount of heat absorbed in the evaporator and suction line, and any heat of compression generated by the compression process.
What should the amperage draw be of a compressor in which the nameplate says the RLA (rated load amperage) is 59.6, but the compressor is only pulling 45 amps? Is there a problem here? Do we need to change the compressor?
The problem: A piston-type reciprocating compressor has valve damage, or the valves are not sealing for some reason. The result: an inefficient compressor. This is one of the most difficult service problems to diagnose because the system may still have some cooling capacity.
A common cause of premature reciprocating compressor failure is overheating. A recip that is running too hot will surely fail before its time. A service tech should always look for this potential problem while servicing any refrigeration system.