NM HVAC Contractor study guide
NM HVAC Contractor · Work through your exam, one topic at a time.
The New Mexico HVAC contractor credential is a mechanical (MM-98) trade license issued through the state's Construction Industries Division. It authorizes a business to contract for the installation, alteration, repair, and service of heating, ventilating, air conditioning, and related refrigeration systems in New Mexico. The NM HVAC Contractor study guide has 11 sections and about 3,575 words.
01New Mexico Contractor Licensing Law and Regulation (Construction Industries Licensing Act, NMAC Title 14 Chapter 6)
New Mexico regulates mechanical contracting through the Construction Industries Division (CID) of the Regulation and Licensing Department. The governing statute is the Construction Industries Licensing Act (NMSA 1978, Chapter 60, Article 13); the rules sit in NMAC Title 14, Chapter 6, and the mechanical code is adopted at 14.6.4 NMAC, built on the Uniform Mechanical Code as amended by New Mexico.
359 words, about 2 min02Business Management
Sole proprietorship, LLC, S corporation, or corporation changes liability, taxation, and how the CID license is held. The license must be in the exact legal name of the entity, with a qualifying party attached.
328 words, about 2 min03Contracting, Estimating, Bidding, and Project Administration
Bids rest on the drawings, specifications, addenda, and pre-bid clarifications. Read addenda before pricing - they change scope.
290 words, about 1 min04Safety, Occupational Health, and Jobsitepractices (OSHA and NM Occupational Health and Safety)
Private-sector HVAC work in New Mexico is enforced by federal OSHA under 29 CFR 1926, the construction standards. The New Mexico Occupational Health and Safety Bureau, part of the Environment Department, runs a state plan covering public employees - state, county, municipal, and school district workers.
337 words, about 2 min05Load Calculations, Psychrometrics, and Equipment Sizing (Manual J, S, and D principles)
ACCA Manual J, eighth edition, is the residential load method: room-by-room and block loads from envelope U-factors, glass area and orientation, SHGC, internal gains, infiltration, ventilation, and duct gain or loss. Use ASHRAE design conditions for the actual city - heating at the 99 percent dry bulb, cooling at the 1 percent dry bulb with its coincident wet bulb.
288 words, about 1 min06Heating Equipment: Furnaces, Boilers, Combustion Air, and Venting
Furnaces fall into four categories by flue pressure and temperature. Category I - the common 80 percent AFUE fan-assisted furnace - vents under negative pressure in Type B vent or a listed liner.
329 words, about 2 min07Cooling Equipment, Refrigeration Cycle, and Refrigerant Handling (EPA Section 608)
Compressor raises refrigerant pressure and temperature; the condenser rejects heat and subcools the liquid; the metering device - TXV, EEV, or fixed piston - drops pressure into the evaporator, where refrigerant boils and absorbs heat, leaving superheated vapor for the compressor. Measure, do not guess: superheat is suction line temperature minus saturated suction temperature; subcooling is saturated liquid temperature minus liquid line temperature.
352 words, about 2 min08Air Distribution, Duct Design, Fans, and Indoor Air Quality
Duct design starts with available static pressure: rated blower external static pressure minus the pressure drops of coil, filter, grilles, and diffusers. Friction rate equals available static pressure times 100 divided by total effective length, and TEL counts straight runs plus the equivalent length of every fitting.
338 words, about 2 min09Electrical Components, Controls, Motors, and Wiring for HVAC Systems
Use the equipment nameplate, not rules of thumb. Minimum circuit ampacity (MCA) sets minimum conductor ampacity; maximum overcurrent protective device (MOP) sets the largest breaker permitted.
324 words, about 2 min10Piping, Sheet Metal, and Materials Installation Standards
Use ACR copper, deburr and ream, and braze with 5 to 15 percent silver alloy while purging dry nitrogen through the line to prevent internal oxidation. No flux on refrigerant joints.
324 words, about 2 min11Code Compliance, Permits, Inspections, and Energy Code (NM Energy Conservation Code, ASHRAE 90.1/90.2, IECC)
The New Mexico Mechanical Code is adopted at 14.6.4 NMAC, based on the Uniform Mechanical Code with state amendments. A permit is required before installing, altering, or replacing HVAC equipment and duct systems; the licensed contractor pulls it, posts it, and calls for inspections.
306 words, about 2 min