In most cases, refrigeration failure, the compressor must be checked first. We must look for other signs of problems during check of the compressor. However, in satisfactory working condition of the compressor must be defined.
The number and condition of the oil in the compressor important. Some compressors oil level sight glass or port. Others have a connector situated on the proper oil level. The two most common causes the compressor trouble defective valves and seal failure. Noisy valves can be detected by a sharp clicks in the compressor how it works.
Leaky valves can be found as follows:
Install the sensor manifold and leak testing. Turn the suction service valve stem all the way to close the suction line. Switching on and off for a few seconds. This is done until the danger of oil pumping stopped. Let the compressor is operating.
Write the best vacuum derived from the normal water pressure refrigerant is used. Also record the time. The compressor must produce vacuum more than 20 Hg (34 kPa) on the background of normal water pressure.
If it is not, in most cases it should be revised.
worn piston or cylinder is indicated clicks. This noise is a little more boring than a noisy valve display mentioned earlier. Worn connecting rod and main bearings are quite noisy when the compressor is running from low suction pressure.
The compressor has to pump a certain volume of gas at a certain pressure difference. It is necessary to do the necessary work. It is difficult to check banks, so just described methods are used as secondary inspection. Some repair shops to use in the store is mounted on the foredeck. Compressor pumps air into these tanks In testing. The time required to pump 150 psi (1140 kPa) is recorded for each size of the compressor. Thus the relative volumetric efficiency you can verify. Compressor testing methods:
The ability to create a vacuum.
The ability to retain high pressure.
The ability to hold both vacuum and pressure head.
If the outlet valve of the compressor leakage, there are two ways to check:
High pressure will flow back through the exhaust valve. Pressure on the sensor connection will be made. Thus, the connection of the sensor creeping above 0 psi (101.3 kPa), when the compressor is in standby means the exhaust valve is in need of repair. Leak on the low side (print) compressor will only cause pressure to rise approximately 0 psi.
Turn discharge service valve stem. If the discharge valve leakage, pressureas indicated by the high pressure sensorwill decrease, especially compressor is switched on manually. (The pressure drops as the piston goes down.) Thus, if over-pressure varies considerably, it indicates a leaky valve. If you simply increases the pressure and does not fall back much exhaust valve is not leaking.
The failure of the compressor for high vacuum indicates the intake valve leakage. However, the vacuum produced persists after the compressor is off, provided exhaust valve holding. The failure of the compressor for high vacuum can also be related to other factors. They include too thick pad or worn piston rings I. oil Shortage will also lead to reduced pumping ability.
The following method is used to determine the crankshaft seal leakage. Close the suction sendee valve. High vacuum pump, to the extent possible, in the crankcase of the compressor. Then turn discharge service valve to another, as shown in Fig. 15-50. Keep the operation of the compressor. Head pressure is displayed on the gauge at the A. It will gradually increase with the compressor is running, if there is a low-side leakage. This indicates that gas or air is drawn into the compressor of the bottom side. Traces of oil in print or on the floor under point to seal the leak. Leak detectors can also be used to check for sealing leaks. (Crankcase pressure should be more psig 0.)
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