unit 10

fractionation occurs when: a. some of a blended refrigerant evaporates or condenses before the rest of the blend b. when only a fraction of the total charge has been added to a system c. the operating pressures of a system increase d. both a and c

A. some of a blended refrigerant evaporates or condenses before the rest of the blend

When charging a refrigeration system with a near-azeotropic mixture, what must be done to prevent liquid from entering the system?

Charge as a liquid through the low side using a restrictor

when charging a system with vapor refrigerant from a refrigerant cylinder, the cylinder will become

cold

as refrigerant vapor is removed from a supply cylinder , the pressure in the supply cylinder will

decrease

When adding refrigerant in liquid form into the high-side of the system, the system motor/compressor assembly is running.

false

when the warm refrigerant cylinder is connected to an operating system, the pressure in the cylinder will be _____ than the suction pressure of the system

higher

If a critically charged refrigeration system is over charged, which of the following is a likely result?

increased operating pressures

refrigerant in vapor form is added to an operating system through the ___ side of the system

low pressure

If the tank is a reusable tank, there are no check valves and system refrigerant can enter the tank as long as the system pressure is higher than the pressure in the tank.

true

Using a restrictor, liquid refrigerant can be charged into the low-side of the system with the system operating.

true

when adding refrigerant in vapor form to an operating refrigeration system, the refrigerant must be added to the low-pressure side of the system?

true

when the systems pressures are lower than the pressure in the refrigerant tank, such as when the system has just been evacuated or if the system is out of refrigerant, refrigerant can be added to both the high and low pressure sides of the system?

true

if the pressure in the refrigerant cylinder drops too low to charge a system(cylinder pressure=low side system pressure) how can the technician increase the cylinder pressure?

use warm water to build up pressure, use a heat blanket, 90 F or less.