Refrigerant cycle
HVAC Tools
Thermostat
Furnace
Random
100
What pressure should your gas and liquid line be while checking superheat/subcooling
200 PSI
100
What do we use to check temperature?
Thermometer
100
What color wire is the power
Red
100
What connects the furnace to the ductwork?
Plenum
100
What are the steps to join PVC
1. Cut pipe to length
2. Prime inside fitting and outside of pipe
3. Apply PVC cement to inside fitting and outside of pipe
4. Firmly connect pieces and twist quarter turn
200
How does the refrigerant change throughout the evaporator.
It goes in a Low temp, mow pressure mixture and comes out a low temp low pressure vapor
200
What do we use to check refrigerant pressure?
Manifold/Gauges
200
What does the W1 terminal control?
Heat stage 1
200
What does the blower do
Pushes air over components and throughout the duct system
200
A customer reports that their residential split-system heat pump, which uses R-410A refrigerant, is blowing cool air in heating mode. You check the system and find the following conditions:
- Outdoor ambient temperature is 40°F.
- Indoor return air temperature is 68°F.
- Suction pressure gauge reads 120 PSI.
- Liquid line pressure gauge reads 300 PSI.
- The compressor is running, and the outdoor fan is operating.
- The system has a thermal expansion valve (TXV).
Based on the gauge readings and symptoms, diagnose the most likely problem and explain the steps you would take to confirm your diagnosis and perform the repair.
Reversing valve is stuck in cooling position
300
What component turns the low pressure low temp refrigerant into a high pressure high temp refrigerant.
Compressor
300
What do we use to check gas pressure at the furnace
Manometer
300
Where does the blue wire go?
Common/C terminal
300
What is the "Brains" of the furnace
Circuit board
300
What does A2L stand for?
Slightly flamable
400
At what component does the High temp High pressure refrigerant take on a low pressure low temp state.
Metering device
400
What tool do we use to check motor RPM?
Tachometer
400
What wire would typically go on the W2 terminal?
Black, or brown
400
What type of furnace would you put in a attic with little height to work with
Horizontal furnace
400
Whats are the two differences between a heat pump and a traditional system
Reversing valve and defrost cycle
500
What happens at the evaporator?
The blower pushes air over and through the coil to cool the air, as the refrigerant flows through
500
What do we use to test flu gases
combustion analyzer
500
What does the yellow wire activate?
Condenser/compressor
500
What does the gas spray out of?
Orfices
500
You are called to a home with a 3-year-old high-efficiency furnace and A/C system. The homeowner complains that the system works fine for heating, but the A/C "acts up" intermittently, sometimes running for 30 minutes, other times shutting off after 2 minutes.
- Intermittent Cooling: The A/C sometimes runs, sometimes shuts down randomly.
- No Error Codes: The furnace control board flashes "normal operation" (no error codes) even when the system is off and the house is hot.
- T-Stat Display: The digital thermostat display looks normal (no low battery, no blank screen).
- The Clue: The homeowner says they only notice this happening on sunny days
Bad thermostat(Temperature-induced voltage drop)