HVAC System Service, Diagnosis and Repair

This question has the word EXCEPT. For this question, look for the choice that could NOT fit the described situation. Read the entire question carefully before choosing your answer. All of the following statements are correct regarding an air conditioning performance test, EXCEPT:

• a. Road debris can clog the condenser fins reducing system performance.

• b. To avoid outside odor, operate AC System in RECIRC rather than FRESH mode.

• c. Passenger-side floor being wet is one symptom of a clogged evaporator drain line.

• d. Obstructions of the cabin air filter may cause insufficient air circulation.

During an air conditioning performance test, the technician notices that the compressor outlet is hot. Technician A says this is a normal condition. Technician B says the air conditioning system is overcharged. Who is right?

• a. A only

• B only

• Both A and B

• Neither A nor B

Technician A says when the condenser airflow is restricted the pressure is high in both high and low lines. Technician B says an indication of low refrigerant is when both the high and low sides show low pressure. Who is right?

• A only

• B only

• Both A and B

• Neither A nor B

This question has the word EXCEPT. For this question, look for the choice that could NOT fit the described situation. Read the entire question carefully before choosing your answer. All of the following tasks are performed when replacing an AC compressor, EXCEPT:

• a. Reuse all mounting brackets

• b. Use new gaskets and seals

• c. Use the same or equivalent compressor

• d. Reuse same compressor oil

A compressor clutch will not engage. Power and ground at the clutch coil are good. Which of the following is the MOST likely cause?

• a. Low refrigerant

• b. Locked-up compressor

• c. Incorrect air gap

• d. Bad pressure cycling switch

On a manual air conditioning system without automatic control, the compressor clutch does not operate. Technician A says there is a failed compressor thermal protector. Technician B says there is an incorrectly adjusted temperature door. Who is right?

• a. A only

• b. B only

• c. Both A and B

• d. Neither A nor B

Using a DMM (digital multimeter), a technician measures 12 volts at the clutch coil, but it will not engage. Technician A says a bad clutch coil could be the cause. Technician B says a bad clutch coil ground could be the cause. Who is right?

• a. A only

• b. B only

• c. Both A and B

• d. Neither A nor B

This question has the word EXCEPT. For this question, look for the choice that could NOT fit the described situation. Read the entire question carefully before choosing your answer. All of the following issues regarding a receiver/dryer are correct, EXCEPT:

• a. Clogged filter can cause higher than normal pressure

• b. Saturated desiccant can cause a blockage due to freezing

• c. You install a new desiccant bag on some systems before charging the system.

• d. Evacuating system removes moisture from a saturated receiver/dryer

This question has the word EXCEPT. For this question, look for the choice that could NOT cause the described situation. Read the entire question carefully before choosing your answer. All of the following are true regarding the expansion valve, EXCEPT:

• a. When stuck closed, pressure on high side is low and pressure on low side is high.

• b. It can fail in the open position as a result of debris in the system.

• c. It can seize in the closed position due to a lack of lubricant.

• d. With moisture in the system, ice can form and cause blockage.

Which of the problems listed below will cause the manifold

gauge readings shown in the illustration?

• a. Refrigerant overcharge

• b. Low refrigerant

• c. Expansion valve stuck closed

• d. Restricted condenser airflow