Many low and medium temperature single-phase compressors require some type of external relay to assist in the starting of its motor. The purpose of this relay is to remove the motor’s start winding, start capacitor, or both, from the circuit once the motor is running.
In a properly operating system, the refrigerant will be in a superheated state from the last section of the evaporator to the first section of the condenser. Technicians can measure the superheat condition anywhere along this path. One common location is at the outlet of the evaporator.
A service technician should not only fix the problem but also, to the best of his ability, ensure the system operates reliably. This means once a technician identifies the system problem, he should try to discover why the failure occurred and what can be done to prevent it from happening again.
Being able to efficiently interpret ladder (line) diagrams is an important part of electrically troubleshooting many HVACR systems. These diagrams are drawn in such a format that it is quite easy to understand the electrical configuration of the system.
The automatic expansion valve (AXV) is similar in construction and appearance to the commonly used thermostatic expansion valve (TXV). However, the metering devices operate much differently.
A popular metering device used on many fractional horsepower refrigeration systems is the cap tube. But one field problem encountered with this type of metering device is that it can become plugged with system debris, causing a restriction.
Technicians need to work smarter, not harder. One major difference between an inexperienced tech and an experienced one is that the experienced tech works smarter. Here are some ways a technician can work smarter and become more efficient.
There are many different types of refrigerant used in our industry today. They are produced by several different manufacturers and have numerous ways of identification. One proper method of identification is referring to a refrigerant by its ANSI/ASHRAE designation.
Evacuating a refrigeration system can be a very time-consuming task. There are several factors that influence the speed of this process. A technician has no control over many of these factors, but there are some areas in which he can help speed up the process.
One type of starting relay used on fractional horsepower compressors is the positive temperature coefficient (PTC) relay. It performs the same function as a current relay or potential relay but in a much different manner.