When the discharge pressure is too high in refrigeration system, why is high pressure control installed?
When the discharge pressure is too high in refrigeration system, why is high pressure control installed? Correct Answer To stop the compressor
Compressors which are installed in the VCRS cycle are set to operate under the design conditions. These compressors are subjected to abnormal conditions which arises out of fluctuations of electric supply, heat load, ambient conditions, etc. Some protective devices, as well as control equipment, are incorporated to maintain the designed working conditions.
The protective devices are discussed below:
High and low-pressure cut-outs these protective devices are a type of electrical switch provided to the refrigeration system such that as soon as the pressure goes up beyond the operating limits, the refrigeration stops, i.e. compressor is stopped.
High-Pressure cut-out: High-pressure cut-out stops the compressor when the pressure goes beyond the condensing temperature set on the device.
Low-Pressure cut-out: Low-pressure cut-out stops the compressor when the evaporator pressure falls below certain limit as adjusted on the device.
The compound cut-out has an arrangement to limit the upper and the lower pressure limits.
Other device to control the compressor:
Over-current and overheating protector: These are the most common in sealed units. This device is either fitted inside or outside the sealed cover, depending upon manufacturers. The protector consists of a bimetallic disc and a series of heating coil or thermistor. The protective devices usually operate and turn off the electric supply when the over-current causes overheating.
