Exam 55: Heating and Air Conditioning Diagnosis and Service

Identify three safety hazards to be aware of when working with refrigerant.

The high- and low-pressure fittings must be changed during an R-12 to R-134a conversion.

A vehicle is being diagnosed for poor A/C performance. The engine is started, and when the system is set to MAX A/C, the compressor engages normally. When the temperature control knob is moved from hot to cool, only hot air blows out of the A/C outlets. Technician A says there is a problem with the air duct system or the controls. Technician B says the system is low on refrigerant. Who is correct?

The leak-test dye in an A/C system will appear luminous yellow-green when illuminated by a(n)_____ light.

Moisture mixed with R-134a produces ____________________ acid.

R-12 and R-134a _____.

A manifold gauge set is used to determine both high-side and low-side pressures in the refrigeration system.

Technician A says pinhole leaks in the evaporator may be caused by acid formed when water and refrigerant are mixed. Technician B says leaks are most often found at hose connections and at the various fittings and joints in the system. Who is correct?

A single drop of water in an A/C refrigeration system may cause damage to the system.