Q)How will you get to know out alr in the system and how to remové it

Ans - How air go into the system-
1. During maintenance time most of the chance air go into the system so after maintenance. you have to use the vaccum pump so that you can remove the alr from the system
2. During charging of the refrigerant or oil air might go Into the system
3. LP cut out not working_properly and system go under vaccum and due to this air come inside the system.

How will you know thé presence of air in the refrigerant system.

a. High condenser pressure
b. Small bubbles in the sight glass
C. Compressor discharge pressure high/running hat
d. More superheat
e. Pressure fluctuations
f. Inefficient working

Now how to remove air from the system -

FOR PURGING AIR

a) In the normal operation of the system, measure the liquid refrigerant pressure,and
temperature at the outlet of the condenser/reservoir.

b).Check the corresponding saturation temperature for the recorded pressure of the liquid refrigerant from the P-T chart for the same the same refrigerant.

c)Now if the value doesnt match it means there is air in the system.

Then,
d.)With the condenser liquid refrigerant outlet valve closed, circulate cooling water, start the compressor and pump down the liquid to the condenser/reservoir.

e.)Circulate the cooling water till the cooling water outlet and the inlet temperatures equal, a check to ensure complete pump down operation.

f). Release air from the condenser, through the vent cock or purging valve until the temperature of the refrigerant in the condenser corresponds to the temperature at the sea water outlet temperature.