Apprentice Path

Electrical, motors, controls and the major equipment types, then your first diagnostics.

1. 01Series and Parallel Circuits
   Concept
   How HVAC wiring is arranged, and why safety devices are in series while loads are in parallel.
2. 02Multimeter
   Tool
   The core electrical instrument, what each function measures, and how to use it safely.
3. 03Clamp Meter
   Tool
   Measuring current without breaking the circuit, and reading amp draw against the data plate.
4. 04Control Transformer
   Component
   The component that creates the 24 volt control circuit, how it is sized, and why its fuse keeps blowing.
5. 05Contactor
   Component
   The low voltage controlled switch that connects line voltage to the outdoor unit.
6. 06Relay
   Component
   A low current coil switching a higher current load, and the relay types you meet in HVAC controls.
7. 07Run Capacitor
   Component
   What a run capacitor actually does for a motor, and how to tell when it has failed.
8. 08Start Capacitor and Hard Start Kit
   Component
   What a start capacitor does during the first moments of a motor start, and when a hard start kit is appropriate.
9. 09PSC Motor
   Component
   The permanent split capacitor motor used in many blowers and condenser fans, and how it behaves as duct resistance rises.
10. 10ECM Motor
    Component
    Electronically commutated motors, the difference between constant torque and constant airflow, and how to troubleshoot them.
11. 11Thermostats and Control Wiring
    Component
    What each control wire does, how thermostat types differ, and how to troubleshoot a control circuit.
12. 12Gas Furnace Sequence of Operation
    Concept
    Step by step through a call for heat on a modern induced draft furnace, and what each step proves.
13. 13Ignition Systems
    Concept
    Standing pilot, intermittent pilot, hot surface and direct spark ignition, and how each proves flame.
14. 14Flame Sensing and Rectification
    Concept
    How a furnace proves flame with a single rod, and how to measure and interpret the microamp signal.
15. 15Pressure Switch
    Component
    Safety switches that prove draft or protect a refrigerant circuit, and how to read what an open switch is telling you.
16. 16Limit and Rollout Switches
    Component
    Temperature safeties that shut down heating equipment, and what each one is actually reporting.
17. 17Hermetic Compressor
    Component
    The pump at the heart of the refrigeration circuit, common types, and how to evaluate one before condemning it.
18. 18Metering Devices
    Component
    Fixed orifice, thermostatic expansion valve and electronic expansion valve, and how each controls the evaporator.
19. 19Reversing Valve
    Component
    The four way valve that lets a heat pump swap the roles of the indoor and outdoor coils.
20. 20Heat Pump Defrost Cycle
    Concept
    Why an outdoor coil frosts in heating, how the control decides to defrost, and what normal defrost looks like.