Bob got a call from the dispatcher to go to an office building that has a 3-ton heat pump compressor that has been shutting off after startup. The fan would continue to run. The building maintenance man said that he had observed the shutting down of the compressor several times.
Nearly 55,000 people ambled through the Las Vegas Convention Center during three days of non-stop activity at the industry’s largest trade show. A typical Wednesday at the expo is usually considered a light day for foot traffic. But even on the last day of the show, attendees were drawn to the 1,800-plus exhibitors’ booths displaying the latest HVACR products.
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.
Although a capillary tube can become totally restricted, a far more common problem is when it becomes partially restricted, allowing some refrigerant to flow into the evaporator but not enough to satisfy the requirements of the system. This seemingly easy problem to diagnose is actually rather tricky at times.
Thermostatic expansion valves (TXV) are responsible for metering the proper amount of refrigerant into an evaporator coil. When they fail, they either cause the evaporator to be flooded (overfed) or starved (underfed) for refrigerant. Read more and find out how to diagnose a defective TXV.
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.
Many larger compressors in the refrigeration and air conditioning field have forced-oiling systems. These compressors are usually over 5 hp. They contain an oil pump located at the end of the compressor’s crankshaft. The crankshaft is actually connected to the oil pump and supplies power, which turns the oil pump.
Historically, the two predominant motor types have been permanent split capacitor (PSC) single-speed motors and 2.3 electronically commutated motors (ECMs) with variable-speed capability. This article looks at and compares the benefits of constant torque motor technology.
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.