Head Pressure (High Side)
Pressure will vary with refrigerants. In air-cooled condensers, the head pressure should be between 30F (17C) and 35F (19C) higher than that of the environment (ambient) temperature of the air passing through the condenser. The water-cooled condenser, head, should correspond to a temperature of 15F (8C) 20F (11 "'Q higher the temperature of the exhaust gases from the water. Using this information, proper head pressure refrigerants can be found. Cm. Fig. 9-2 and 9-20. Read the chart.
In all cases, condensation temperature will rise until the loss of heat from the condenser is equal to the supply of heat in the condenser. If the condensing pressure is too high, the compressor has to work very hard.
pair remains in compressor design pocket. This reduces the volumetric efficiency. The temperature of the exhaust steam is too high and could lead to oil deterioration. Common reasons for higher standards of Chapter pressure are listed below:
- In noncondcnsable vapor or gas, such as air, caught in the condenser.
The head is the sum of the pressure of the refrigerant vapor plus air pressure. This is due to Dalton's Law.
- Overstatement of the rates of the refrigerant in systems with low side of the float, expansion valve, or thermostatic expansion valve. Some of the heat-radiating space in the condenser will fill with liquid refrigerant and reduce the condenser heat-radiating ability.
- Either inside or outside condenser dirty. This dirt will act as an insulator, lowering the heat-radiating capacity of the condenser. Then, the condenser, the temperature will rise,
- Air or water movement through the capacitor is reduced by blocking the aisles or poor water flow. When this happens, there will not be enough heat-removing material to transfer heat from the condenser.
- Limitation in the system, such as a clogged capillary tube or stuck refrigerant control. This can lead to temporary high pressure.
- Above the normal low pressure. When this happens, the head, the pressure is higher than usual.