NJ HVAC Contractor flashcards
NJ HVAC Contractor · Build recall with a focused review session.
32 cards. Read the term and the definition here. The deck at the top of this page is optional.
- Superheat
- The temperature of refrigerant vapor above its saturation temperature at a given pressure. Measured at the evaporator outlet; indicates proper refrigerant charge and expansion valve operation.
- Subcooling
- The temperature of liquid refrigerant below its saturation temperature at a given pressure. Measured at the condenser outlet; used to verify charge in TXV systems.
- Ton of refrigeration
- A cooling capacity equal to 12,000 Btu per hour, or 200 Btu per minute, or 3.517 kilowatts. Based on the heat absorbed by melting one ton of ice in 24 hours.
- TXV
- Thermostatic expansion valve. A metering device that maintains constant superheat at the evaporator outlet by modulating refrigerant flow in response to temperature and pressure.
- AFUE
- Annual Fuel Utilization Efficiency. A measure of heating equipment efficiency over a full heating season. Minimum 80% for standard furnaces; 90%+ for condensing furnaces.
- Condensing furnace
- A furnace that recovers latent heat from flue gases by condensing water vapor, achieving 90%+ AFUE. Uses PVC venting because flue gas temperature is low.
- Hartford loop
- A piping arrangement on a steam boiler that prevents water from siphoning out and maintains a safe water level. It connects the equalizer and return piping.
- Combustion air
- Air supplied to a fuel-burning appliance for complete combustion. Required by code to prevent incomplete combustion and carbon monoxide production.
- Defrost cycle
- A heat pump mode that melts frost from the outdoor coil. It may reverse the refrigerant cycle or use electric heat, and is controlled by time-temperature or demand sensors.
- Balance point
- The outdoor temperature at which a heat pump's heating capacity equals the building's heat loss. Below this point, auxiliary heat is required to maintain indoor temperature.
- Evacuation
- Removing moisture and non-condensable gases from a refrigeration system using a vacuum pump. Typically evacuated to 500 microns or less with a decay test.
- POE oil
- Polyolester oil, used with R-410A and other HFC refrigerants. It is hygroscopic, absorbing moisture quickly, so systems must be kept sealed and dry.
- Manual D
- ACCA's residential duct design method. It determines duct size based on available static pressure, friction rate, and equivalent length of fittings.
- Equivalent length
- The straight-duct length that would produce the same pressure drop as a fitting. Used in duct sizing to account for elbows, tees, and other fittings.
- MERV
- Minimum Efficiency Reporting Value. A rating for air filters from 1 to 16 (higher is better). MERV 8–13 is typical for residential HVAC systems.
- Static pressure
- The resistance to airflow in a duct system, measured in inches of water column. Used to determine blower performance and duct sizing.
- PSC motor
- Permanent split capacitor motor. A common blower motor with a run capacitor; less efficient than ECM but simple and reliable.
- ECM
- Electronically commutated motor. A brushless DC motor with integrated electronics, providing high efficiency and programmable airflow.
- Contactor
- An electrical relay used to control high-power circuits. It has a low-voltage coil and normally open contacts for compressor or fan power.
- C terminal
- The common terminal on a low-voltage thermostat. It provides 24V power to the thermostat and is required for smart thermostats.
- Manual J
- ACCA's residential load calculation method. It determines heating and cooling loads based on envelope, orientation, and internal gains.
- Design temperature
- The outdoor temperature used for sizing HVAC equipment, typically the 0.4% cooling and 99% heating design values for the location.
- 400 cfm per ton
- A nominal airflow rule for cooling systems. It provides about 400 cubic feet per minute of air per ton of cooling capacity.
- Manual S
- ACCA's equipment selection method. It matches the calculated load to equipment capacity, ensuring proper sizing without oversizing.
- NJ UCC
- New Jersey Uniform Construction Code, N.J.A.C. 5:23. It adopts the International Codes with NJ amendments and governs construction, including HVAC.
- Master HVACR license
- A New Jersey license issued by the Division of Consumer Affairs. It allows the holder to contract for HVACR work and supervise apprentices.
- Construction official
- The local official who enforces the NJ UCC, issues permits, and conducts inspections. Appeals go to the Construction Board of Appeals.
- EPA Section 608
- Federal regulations requiring certification for technicians who handle refrigerants. It sets recovery, recycling, and reclamation requirements.
- Combustion air openings
- Permanent openings that supply air to fuel-burning appliances. For confined spaces, each opening is sized at 1 square inch per 1,000 Btu/h input.
- Category IV venting
- Venting for condensing appliances with positive flue pressure and low flue gas temperature. Typically uses PVC or CPVC pipe.
- Change order
- A written modification to a construction contract that changes scope, cost, or schedule. It must be signed by both parties before work proceeds.
- Retainage
- A percentage of payment withheld by the owner until final acceptance. Typically 5–10% and released after final inspection and punch list completion.