Q&A STUDY GUIDE GRADED A+
◉What is the common suction line on a heat pump connected to?
Answer: The indoor coil and the compressor.
◉What are the two generally used methods for changing capacity on
demand in a heat pump? Answer: Two speed compressor. Two stage
thermostat
◉What are the three things that happen when a heat pump is cycled
into the defrost mode? Answer: Reversing valve switches to cooling
mode, Outdoor fan is shut off, and auxiliary heat is energized.
◉What is a duct system that has a single trunk extending in one or
two directions with many branch ducts? Answer: Extended Plenum
Duct System
◉What is the effect on supply airflow when static pressure on the
return is reduced? Answer: Airflow will be increased.
◉What is the voltage most often used to power the outdoor unit in a
residential system? Answer: 240V Single Phase
, ◉What happens if you increased suction pressure on a reciprocating
compressor? Answer: The capacity would decrease.
◉The refrigerants typically used in residential and light commercial
pumps have a storage life of? Answer: An indefinite length of time.
◉A restricted drier can cause what? Answer: Lower than normal
suction pressure
◉What blower motor type is generally used on air handling
equipment with capacities of 4,000 cfm or greater? Answer: Belt
driven with three phases.
◉Electronic air cleaners can operate with internal voltages as high
as? Answer: 5000V
◉What is the purpose of a cross break on the flat sides of metal
ductwork? Answer: Increases rigidity and reduces vibration
◉Whats the difference between a grille and a register? Answer:
Register is equipped with a air volume control device, grille is not.