Question 1

The ____ valve provides a bypass around the condenser.&#10;A) metering&#10;B) ORI&#10;C) master&#10;D) ORD

Accepted Answer

The ORD (Open on Rise of Differential) valve is used to bypass the condenser when the pressure differential across it rises, allowing refrigerant to bypass the condenser.

Question 2

A pressure-operated piston is used to open the ____ and permit more air to flow.&#10;A) shutters&#10;B) valves&#10;C) contacts&#10;D) switches

Accepted Answer

shutters

Question 3

One common method of increasing head pressure is by controlling the amount of air across the condenser.

Accepted Answer

Controlling the amount of air across the condenser can increase the head pressure by increasing the heat transfer rate and ultimately the refrigerant's condensation temperature.

Question 4

An advantage of shutters is that they open and close slowly maintaining an even ____.&#10;A) output voltage&#10;B) head pressure&#10;C) output temperature&#10;D) speed

Accepted Answer

Shutters are often used in systems to control the flow of fluids or gases, and by opening and closing slowly, they help maintain an even head pressure. This gradual operation prevents sudden changes in pressure that could disrupt system operations or cause damage.

Question 5

One type of fan cycle control employs a ____ to control motor speed.&#10;A) thermistor&#10;B) triac&#10;C) thermostat&#10;D) shutter

Accepted Answer

A triac is a type of electronic switch that can be used to control the speed of a motor in a fan cycle control. It works by regulating the amount of power that is delivered to the motor, which in turn affects its speed. A thermistor is a type of temperature sensor, while a thermostat is a device used to regulate temperature in a room or building. A shutter is a mechanical component used to control the flow of air or light.

Question 6

The fan cycle switch can be added to an existing system with very little trouble.

Accepted Answer

The fan cycle switch can easily be added to an existing HVAC system without much difficulty or extra installation.

Question 7

Condenser flooding is accomplished by placing a pressure operated valve in the refrigerant line between the condenser and metering valve.

Accepted Answer

Condenser flooding can indeed be achieved by using a pressure operated valve in the refrigerant line between the condenser and metering valve. This valve is designed to regulate the flow of refrigerant to the evaporator in response to changes in pressure, allowing for proper cooling and condensation to occur within the system. By carefully controlling the flow rate of refrigerant, it is possible to flood the condenser and achieve optimal system performance.

Question 8

Air-cooled condensers of large refrigeration units and air conditioners employ a(n) ____ to increase airflow across them.&#10;A) receiver&#10;B) evaporator&#10;C) fan&#10;D) ORI valve

Accepted Answer

Air-cooled condensers require a fan to increase airflow across them as this helps to dissipate the heat absorbed by the refrigerant. The other options (receiver, evaporator, and ORI valve) do not play a role in increasing airflow.

Question 9

Air conditioning systems operate at lower temperatures than refrigeration systems, and must employ some method for defrosting the evaporator.

Accepted Answer

Air conditioning systems generally operate at higher temperatures compared to refrigeration systems, which often require lower temperatures to preserve food or other perishable items. Defrosting the evaporator is more commonly a concern for refrigeration systems, especially those operating at or below freezing temperatures, to maintain efficiency and prevent ice buildup.

Question 10

The ORD valve is an inlet pressure regulating valve that responds to changes in the condenser pressure.

Accepted Answer

The ORD valve, or Oil Return Differential valve, is designed to regulate the flow of oil back to the compressor in a refrigeration system, not to respond to changes in condenser pressure.

Deck 47: Refrigeration Controls