HVAC Final Exam, unit 10

If 22 oz. of refrigerant are to be added to a refrigeration system and the supply cylinder weighs 24 lb. 12 oz. before any is added, what will be the supply cylinder weight after the system has been charged?

23 lb. 6 oz.

If 30 oz. of refrigerant are to be added to a refrigeration system and the supply cylinder weighs 26 lb. 4 oz. before any is added, what will the supply cylinder weigh after the system has been charged?

24 lb. 6 oz.

The factory charge in a split system, using R-22, shows 6 lb. 8 oz. in the outdoor condensing unit and 2 oz. in the evaporator. The 3/8" liquid line contains 0.48 oz. per foot and the 7/8" suction line contains 0.10 oz. per foot. The refrigerant lines are 30' long. What is the correct refrigerant charge for this system?

7 lb. 11 oz.

A graduated cylinder charging device is a device that?

All of the above

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?

Fall

True/False: 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.

False

True/False: The quickest method to charge a system is to charge only vapor.

False

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

False

The charging device that holds refrigerant, has a visible column of liquid, and can be used to "visually" see the amount of refrigerant used is called the_______.

Graduated cylinder

When the refrigerant cylinder is connected to an operating system, the pressure in the cylinder will be_______ than the suction pressure of the system.

Higher

The_________ is used to help technicians perform a number of tasks including taking pressure readings on the high side of the system and trapping all the system refrigerant in the receiver to perform system service.

King Valve

Refrigerant in line form is normally put into the system through the?

Liquid line

Refrigerant in vapor form is added to the system through the _____ side of the system.

Low

Fractionation occurs when?

Some of a blended refrigerant evaporates and condenses before the rest of the blend

Refrigerant in vapor form is normally put into the system through the?

Suction line

True/False: A manufacturer's charging chart may be used when available to determine the correct charge for a system.

True

True/False: Glide is the range of temperatures/pressures in which a blended refrigerant will condense.

True

True/False: One good feature of an electronic charging scale is that it counts upward as refrigerant is removed, to tell the technician how much refrigerant was used.

True

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

True

True/False: When adding refrigerant in vapor form to a refrigerant system, the system motor/compressor assembly is running.

True

True/False: When the system pressure 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

When charging liquid refrigerant from a single valve supply cylinder, the cylinder is placed___.

Upside down

Charging a refrigeration system refers to?

adding refrigerant to a system

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

increased operating pressures