NV HVAC Contractor cheat sheet

Nevada State Contractors Board (NSCB) licenses HVAC contractors; a C-21 license covers refrigeration and air conditioning, and a C-1 covers heating and plumbing.

General building contractor (B) license may perform HVAC work only if it is incidental to the primary construction; otherwise a specialty license is required.

License classifications: A (general engineering), B (general building), C (specialty). HVAC work typically requires C-21 or C-1.

Bid limits: A and B licenses have no monetary limit; C-21 and C-1 licenses have a limit set by the Board based on financial statements and experience.

Qualifying party must be a licensed contractor or a qualified employee with required experience; they must be actively involved in the business.

License renewal: every two years; continuing education may be required (check current NSCB rules).

Grounds for disciplinary action include: abandonment, failure to comply with building codes, diversion of funds, and aiding unlicensed contracting.

Contract requirements: written contract for jobs over $500 must include specific notices (e.g., lien rights, cancellation).

NSCB may require a surety bond and cash deposit as a condition of licensing; bond amounts vary by license type.

AFUE (Annual Fuel Utilization Efficiency) measures seasonal efficiency of furnaces; minimum 80% for standard, 90%+ for condensing.

SEER (Seasonal Energy Efficiency Ratio) and SEER2 for cooling; higher SEER indicates greater efficiency. Minimum SEER2 in Nevada varies by region.

HSPF (Heating Seasonal Performance Factor) for heat pumps; higher is better.

Heat pump balance point: outdoor temperature at which heat pump output equals building heat loss; below this, auxiliary heat is needed.

Furnace types: natural draft, induced draft, condensing; condensing furnaces require PVC venting and condensate disposal.

Air handlers: draw return air, filter, heat/cool, and distribute via ductwork; can be upflow, downflow, or horizontal.

Packaged units combine heating and cooling in one cabinet; split systems have separate indoor and outdoor units.

Chillers: use water or air-cooled condensers; efficiency measured in kW/ton (lower is better) or EER/IPLV.

Variable refrigerant flow (VRF) systems modulate refrigerant flow to indoor units for precise zone control.

Manual J (ACCA) is the standard for residential heating and cooling load calculations; considers orientation, insulation, windows, infiltration, and internal gains.

Heating load: sum of transmission losses (U×A×ΔT) and infiltration/ventilation losses; no solar gain credit.

Cooling load: sum of transmission gains, solar gains through glass, internal gains (people, lights, appliances), and infiltration/ventilation gains.

Manual D (ACCA) for duct design: determines duct sizes based on friction rate, equivalent length, and available static pressure.

Duct sizing methods: velocity reduction, equal friction, static regain. Equal friction is common for supply ducts.

Air distribution: supply outlets should be selected for throw, drop, and spread to avoid drafts; return air paths must be sized to minimize pressure drop.

Duct leakage: seal all joints; leakage can waste 20-30% of conditioned air. Use mastic or UL 181 tape.

Flexible duct: limit length and avoid sharp bends; sagging reduces airflow. Use metal elbows for turns.

Balancing: adjust dampers to achieve design airflow at each terminal; use a balometer or flow hood.

Refrigeration cycle: compression, condensation, expansion, evaporation. Refrigerant absorbs heat in evaporator and rejects heat in condenser.

Superheat: temperature above saturation at evaporator outlet; ensures no liquid enters compressor. Subcooling: temperature below saturation at condenser outlet; ensures solid liquid at expansion valve.

Refrigerant types: CFCs (R-12) phased out; HCFCs (R-22) phased out; HFCs (R-410A, R-134a) being phased down due to GWP; HFOs (R-1234yf) low GWP alternatives.

EPA Section 608: requires certification for technicians handling refrigerants; prohibits venting of ozone-depleting refrigerants and their substitutes.

Clean Air Act: production and import of HCFCs banned after 2020; HFC phase-down schedule under AIM Act.

Refrigerant safety classifications: A1 (lower toxicity, no flame propagation), A2L (lower toxicity, flammable), B1, etc. R-410A is A1; R-32 is A2L.

Leak detection: required for appliances with 50+ lbs of refrigerant; repair leaks within 30 days and verify with follow-up.

Recovery, recycling, and reclamation: use EPA-certified equipment; evacuate to 500 microns for new installations.

Ohm's law: V = I × R; power: P = V × I × PF (for AC). Use for sizing conductors and overload protection.

Motor protection: overloads protect against overheating; circuit breakers and fuses protect against short circuits and ground faults.

Locked rotor amps (LRA): current drawn when motor starts; running load amps (RLA) is normal operating current. Use LRA for disconnect sizing.

Contactors and relays: control power to compressors, fans, and heaters. Contacts may be normally open (NO) or normally closed (NC).

Thermostats: low-voltage (24V) controls; use proper wire gauge to avoid voltage drop. C-wire provides continuous power for smart thermostats.

Defrost controls: time-temperature or demand defrost for heat pumps; ensures frost removal from outdoor coil.

Variable frequency drives (VFDs): control motor speed for compressors, fans, pumps; reduce energy use at part load.

Building automation systems (BAS): use sensors, controllers, and communication protocols (BACnet, Modbus) for monitoring and control.

Electrical safety: lockout/tagout, proper grounding, and GFCI protection for outdoor receptacles.

Equipment placement: follow manufacturer clearances for airflow and service access; ensure condensate drain slopes to a suitable discharge.

Line set sizing: follow manufacturer charts for refrigerant lines; excessive length or elevation requires adjustments.

Evacuation: use a vacuum pump and micron gauge; evacuate to 500 microns or below and hold to confirm no leaks.

Charging: weigh in refrigerant for split systems; use superheat/subcooling method for verification.

Duct testing: perform duct leakage test (e.g., pressurize to 25 Pa) to verify tightness; seal leaks as needed.

Airflow measurement: use balometer or anemometer to measure CFM at registers; compare to design.

Combustion analysis: measure CO, CO2, and stack temperature to verify proper combustion and venting.

Commissioning: verify all components operate per sequence of operation; document settings, airflow, and refrigerant charge.

Electrical testing: check voltage, amperage, and insulation resistance; ensure proper phasing for three-phase motors.

Contract types: lump sum, time and materials, cost-plus. Lump sum requires complete plans and specifications.

Lien rights: Nevada requires preliminary notice (20-day notice) to preserve lien rights on private projects; follow deadlines strictly.

OSHA safety: fall protection required above 6 feet; use personal protective equipment (PPE) and follow hazard communication.

Asbestos and lead: follow EPA and OSHA regulations for disturbance in older buildings; certified renovator required for lead-safe practices.

Project scheduling: use Gantt charts or critical path method (CPM) to manage tasks and dependencies.

Change orders: must be in writing and signed before work proceeds; document all changes.

Payment terms: Nevada law requires prompt payment (within 30 days) for undisputed invoices on construction contracts.

Bonding: performance and payment bonds may be required on public works projects; ensure bond capacity.

Recordkeeping: maintain payroll records, contracts, and change orders for at least 3 years (Nevada requirement).