Question

An air conditioner with a fixed restriction metering device is operating with an evaporator saturation temperature of 40 degrees Fahrenheit and a suction line temperature of 42 degrees Fahrenheit. The factory specified superheat for the current operating condition is 12 degrees Fahrenheit. After checking the airflow and determining that it is within specifications, the technician should...

a) Adjust the refrigerant charge
b) Increase the airflow
c) Decrease the airflow
d) No action is needed

Answer 1

The technician should adjust the refrigerant charge since the current superheat is below the factory specified value and the airflow has been confirmed to be within specifications.

Step-by-step explanation:

Given that an air conditioner is operating with an evaporator saturation temperature of 40 degrees Fahrenheit and a suction line temperature of 42 degrees Fahrenheit, we can determine the current superheat by subtracting the evaporator saturation temperature from the suction line temperature. In this case, the superheat is 42°F - 40°F, which equals 2 degrees Fahrenheit. The specified superheat for the air conditioner is 12 degrees Fahrenheit. Since the current superheat is less than the specified value, it indicates that the air conditioner may be undercharged or experiencing another issue causing low superheat.

After confirming that the airflow is within specifications, the technician should adjust the refrigerant charge to increase the superheat to the factory specified value. Therefore, the correct action is:

a) Adjust the refrigerant charge.