Mastering Refrigeration System Components and Safety Procedures Quiz

The defrost termination solenoid is responsible for terminating the defrost cycle once the temperature reaches a certain point. This component is connected to terminals 3 & X of the electro-mechanical defrost time clock.

To test the oil failure control safety contacts, the correct procedure is to install a jumper across the pressure differential switch. This allows for accurate testing of the safety contacts in the system.

The correct method is to test the entire system at the design pressure of its components to ensure it can withstand normal operating conditions.

When replacing a shaft seal on an inline booster, the motor is typically removed first to access the shaft seal for replacement.

When replacing a seal on a close-coupled, end suction pump, the impeller and pump assembly need to be removed, not the motor & coupling bracket, coupling bracket and pump volute, or pump volute and impeller.

The correct distance for pipe supports to be located within a change of pipe direction is 2ft to ensure proper support and stability.

When sizing an exhaust fan, factors such as makeup air units, building space pressurization, and gas-fired appliances must be taken into account to ensure proper ventilation and safety within the building.

In refrigeration, an azeotrope is a mixture of components that act as a single fluid with constant boiling and condensation temperatures. A binary blend with similar pressure temperature characteristics is an example of an azeotrope refrigerant.

Fractionation is the process of separating different components of the refrigerant blend. In the case of vapor charging, ternary blend refrigerants are more likely to fractionate due to differences in volatility of the components.

The issue lies in the fact that the system is vapour charged with a Zeotrope refrigerant, which can be two or more refrigerants mixed together. This mixture may have different boiling points, leading to improper functioning of the system.

When storing recovery cylinders, it is important to follow the correct procedure by ensuring they are secured, the caps are in place, they are stored vertically, and the temperature is below 125F to prevent any safety hazards or damage.

A di-electric union is used to join two different metals, specifically brass to black iron, to prevent galvanic corrosion.

To calculate the refrigerant mass flow rate, we first determine the constant number which is 200 BTU/min/ton. Next, we calculate 200/56 to get 3.57. Multiplying this by the 15 tons of the system gives us 53.57 LB/min. Therefore, the correct answer is d) 53.6 LB/min.

Chilled water coils typically have the cool water entering from the bottom and the warm water leaving from the top to maximize heat exchange efficiency.

The correct configuration for a heat pump reversing valve is to have the pilot on top and the main valve in a horizontal position, allowing for proper functionality.

In a closed loop water system, a chemical pot is usually located on the system supply to introduce chemicals into the system.

240/144 sq.ft. x 360 = 600.

To troubleshoot the issue of a heat pump blowing warm air indoors on a call for cooling, the technician should block off the condenser and switch the thermostat from cooling to heating and back again to identify the problem accurately.

To calculate the voltage unbalance, we first find the average voltage by summing all the voltages and dividing by 3. The average voltage is (597 + 606 + 600) / 3 = 601 volts. Then, we find the difference between the highest and lowest voltages, which is 606 - 601 = 5 volts. Finally, we divide the difference by the average voltage: 5 / 601 ≈ 0.0083 or 0.83%. Therefore, the correct answer is b) 0.8%.

A pneumatic controlled heating valve being in the full open position typically indicates that the valve diaphragm has ruptured, causing the valve to remain fully open.

Carbon filters are commonly used for removing odors because they can effectively trap and neutralize odor-causing particles and gases.

When compressor contactor contacts are chattering, it indicates that the 24 volt circuit is drawing too much current for the transformer. In this case, option a) is the correct answer as drawing 6 amps with a 100 VA transformer is causing the issue.

The increase in high pressure after conversion from R-22 to R-407C is a common issue due to the differences in operating characteristics of these refrigerants.

In a draw-through system, to prevent backflow of condensate from the trap when the fan stops, the depth of the trap should be greater than the measured negative pressure. In this case, since the pressure is -0.25", the required depth of the condensate trap should be 0.30".

To calculate the number of pipes that will fit through the pipe cover, we first determine how much space each pipe takes up. Each 11/8" pipe with 1/2" of insulation will take up 3.125" of space. Considering the 25 mm space between each pipe, which is approximately 0.984", we divide the total length of the sleeve (22') by the combined space occupied by each pipe (3.125") plus the additional space (0.984") to get 7.04. Therefore, the correct answer is 7, as you can only have a whole number of pipes.

4005 x 0.03^2 (velocity pressure) = 680.68 ft/min

The correct way to calculate the cfm of the air across the coil is by multiplying the length and width. In this case, the calculation is 6 x 4 = 24, which results in 16,649ft3/min.

Enthalpy is a measure of the total energy of a thermodynamic system. In this case, the correct enthalpy of the air entering the coil is 28.1 btu/lb. Option a) 22.7 btu/lb, option b) 27.6 btu/lb, and option d) 30.2 btu/lb are incorrect as they do not match the correct enthalpy value.

The correct location for the vapour barrier in a walk-in cooler is between the outer wall and the insulation to prevent moisture from entering the insulation material.