HVAC HVAC Troubleshooting Techniques 2

Question 1

A heat pump runs continuously but fails to reach the set temperature in heating mode. What is the FIRST component to inspect?

Accepted Answer

Outdoor coil for ice buildup

Answer

A frozen outdoor coil severely restricts heat absorption and is the most common cause of a heat pump failing to heat adequately in cold weather.

Question 2

A technician measures superheat of 25°F on a TXV-equipped system. What does this indicate?

Accepted Answer

TXV bulb may have lost its charge or TXV is underfeeding

Answer

High superheat on a TXV system typically points to a restricted or malfunctioning TXV that is underfeeding refrigerant to the evaporator.

Question 3

During a gas furnace call for heat, the inducer motor starts but the ignitor never glows. Which component is most likely at fault?

Accepted Answer

Pressure switch

Answer

If the pressure switch fails to close after the inducer starts, the control board will not energize the ignitor because it has not confirmed proper draft.

Question 4

An air conditioner short-cycles off on the high-pressure cutout. Outdoor ambient is 95°F and airflow over the condenser coil is adequate. What should the technician check next?

Accepted Answer

System refrigerant charge for overcharge

Answer

With adequate condenser airflow and high ambient, an overcharged system is the primary suspect for tripping the high-pressure cutout.

Question 5

A customer reports their split system produces a musty odor whenever it runs. What is the most likely cause?

Accepted Answer

Microbial growth on the evaporator coil or drain pan

Answer

Musty odors from HVAC systems are almost always caused by mold or bacteria growing on the wet evaporator coil surface or standing water in the drain pan.

HVAC - Heating, Ventilation, and Air Conditioning Practice Test

HVAC - Heating, Ventilation, and Air Conditioning Practice Test

HVAC HVAC Troubleshooting Techniques 2