OR HVAC Contractor study plan

Map the Oregon Construction Contractors Board licensing path for an HVAC/R contractor, including the required surety bond amount and liability insurance minimums, and write them from memory.

Explain in writing the difference between a licensed contractor, a registered specialty contractor, and an unlicensed operator under Oregon law, with one example of work each may and may not perform.

Outline the required contents of a residential HVAC contract (scope, price, payment schedule, notice of right to cancel, lien notices) and identify three omissions that commonly trigger complaints.

Calculate load-side airflow using the sensible heat equation Q = 1.08 x CFM x delta-T, working five problems with different entering conditions.

Sketch a basic vapor-compression cooling cycle and label the four components, the two pressures, and the state of refrigerant at each point.

Sequence the steps an Oregon contractor must take when a complaint is filed, from CBB notification through dispute resolution and possible sanction.

Summarize Oregon lien law timelines for a residential HVAC project, including the pre-lien notice, the 75-day window, and the foreclosure period.

Locate the Oregon Residential Specialty Code and Oregon Mechanical Specialty Code adoption structure and state which edition governs permits filed today.

List the permit, inspection, and final-approval sequence for replacing a residential forced-air furnace, naming who may pull the permit.

Draft the records a contractor must retain for employee and subcontractor payroll under Oregon prevailing-wage rules for a public school HVAC retrofit.

Perform a room-by-room Manual J style load estimate for a single-family house using envelope, glazing, and internal-gain inputs, and document assumptions.

Select equipment and size ductwork from a completed load calculation, verifying static pressure budget and supply/return velocities against accepted limits.

Describe the function and failure symptoms of each major refrigeration component: compressor, condenser, metering device, evaporator, and receiver/accumulator.

Explain superheat and subcooling targets for a fixed-orifice and a TXV system, and diagnose three charging faults from gauge readings alone.

Trace refrigerant flow and identify the state at six labeled points on a provided system description, including the difference between a heat pump in heating and cooling mode.

Compare fixed-orifice, TXV, and EEV metering strategies and state which applications each suits and why.

Diagnose five common refrigeration faults (restriction, undercharge, overcharge, non-condensables, bad compressor valves) from a written set of pressures and temperatures.

Explain combustion efficiency, excess air, and stack temperature relationships for a gas furnace and how each affects steady-state efficiency.

Size and lay out a trunk-and-branch duct system for a two-story house, including manual damper placement and return-air strategy.

Describe refrigerant recovery, recycling, and evacuation procedures and the recordkeeping required for appliance disposal under federal refrigerant rules.

Identify the NEC articles that govern HVAC/R branch circuits, disconnecting means, motor overload protection, and hermetic refrigerant motor-compressors.

Calculate minimum conductor ampacity and overcurrent protection for a packaged unit using nameplate minimum circuit ampacity and maximum overcurrent protection values.

Explain Class 2 low-voltage control wiring limits, thermostat circuit types, and the purpose of a C-wire, and wire a basic heating/cooling thermostat from a schematic.

Size a natural gas or LP branch line for a furnace and range using the longest-run method, and state the required sediment trap, union, and shutoff valve locations.

Describe combustion air requirements for a confined space and how a Category IV condensing appliance differs in venting from a natural-draft unit.

Cite the code requirements for appliance clearances, access, condensate disposal, and platform construction for an attic or closet furnace installation.

Explain the inspection points a mechanical inspector will check on a gas furnace changeout and list the documentation to have on site.

Describe the safety sequence of a standing-pilot versus intermittent-ignition furnace and the components that prove flame and draft.

Identify the code and practical requirements for seismic strapping, flex connectors, and protection of gas piping through framing.

Summarize Oregon administrative provisions for code interpretations, appeals, and the role of the local building official versus the state.

List the PPE, lockout/tagout, and refrigerant handling steps required before opening a live electrical panel or a pressurized system.

Describe safe recovery cylinder practices, including filling limits, hydrostatic testing, and cylinder marking.

Explain brazing safety, nitrogen purge, and the fire watch requirements when working near combustible construction.

Outline fall protection, ladder, and attic-access hazards for a typical residential HVAC service call and the controls for each.

Diagnose a refrigerant leak using electronic, ultrasonic, and dye methods, and state when each method is appropriate.

Complete a full-length timed practice exam under test conditions and record the score by domain.

Review every missed item, write the underlying rule or principle, and re-test those items until correct twice.

Re-derive the ten highest-yield formulas (airflow, load, superheat, subcooling, gas pipe sizing, ampacity) from memory.

Rehearse Oregon business-practice scenarios: change orders, payment disputes, warranty obligations, and employee supervision.

Build a final one-page cheat sheet of code citations and limits you tend to forget.