HVAC Ductless Mini-Split Systems 2

Question 1

What is the typical refrigerant line set length limit for most residential ductless mini-split systems without additional refrigerant charge?

Accepted Answer

25 feet

Answer

Most residential mini-split systems are pre-charged for approximately 25 feet of line set; longer runs require additional refrigerant.

Question 2

Which component in a ductless mini-split system is responsible for reversing refrigerant flow to switch between heating and cooling modes?

Accepted Answer

Reversing valve

Answer

The reversing (or four-way) valve redirects refrigerant flow to switch the system between heating and cooling operation.

Question 3

A mini-split indoor unit is producing a musty odor. What is the most likely cause?

Accepted Answer

Dirty or moldy evaporator coil and drain pan

Answer

Mold and mildew growth on the evaporator coil and drain pan is the most common source of musty odors in mini-split air handlers.

Question 4

What does the SEER2 rating measure for a ductless mini-split system?

Accepted Answer

Cooling efficiency over a cooling season

Answer

SEER2 (Seasonal Energy Efficiency Ratio 2) measures the cooling output divided by electrical energy input over a typical cooling season.

Question 5

When installing a mini-split indoor unit on an interior wall, what is the primary concern with the condensate drain line?

Accepted Answer

The drain must slope downward at least 1/4 inch per foot to flow by gravity

Answer

Condensate must drain by gravity, requiring a continuous downward slope of at least 1/4 inch per foot to prevent water backup and overflow.

HVAC - Heating, Ventilation, and Air Conditioning Practice Test