NC HVAC case studies
NC HVAC · Put your knowledge to work in context.
The North Carolina HVAC contractor license is a state credential that lets a business legally bid, install, and service heating, ventilation, air conditioning, and refrigeration work in North Carolina. It is issued at the business level, so the qualifying individual demonstrates technical competence on behalf of the firm they represent. The NC HVAC case studies are 5 cases and about 2,930 words.
1Condensate Trap and Negative-Pressure Coil Diagnosis
A technician is called to a 3-ton upflow air handler installed in a closet. The unit cools, but water is pooling on the closet floor and the ceiling below shows a faint stain.
665 words, about 3 min2Sizing a Replacement System After a Manual J Discrepancy
A contractor is quoting a replacement for a 2,000 sq ft single-story house in central North Carolina with 8 ft ceilings and average window area. The existing 4-ton system short-cycles in mild weather and the homeowner complains of high humidity.
633 words, about 3 min3Gas Furnace Combustion Air and Venting in a Tight Closet
A 100,000 Btu/h induced-draft gas furnace is installed in a 10 ft by 12 ft closet with an 8 ft ceiling and a solid door. The closet also contains a gas water heater rated 40,000 Btu/h with a draft hood.
568 words, about 3 min4Short Cycling, Superheat, and a Restricted Metering Device
A split system with a thermostatic expansion valve (TXV) is cooling poorly. The technician measures: suction pressure 55 psig (R-410A, saturation about 32°F), suction line temperature at the evaporator outlet 62°F, liquid line pressure 250 psig, liquid line temperature 95°F, outdoor ambient 90°F.
524 words, about 3 min5Permit, Contract, and Change-Order Judgment on a Duct Replacement
A contractor signs a fixed-price contract to replace a residential duct system for 9,500, including permits, labor, and materials. The contract states the work will be completed in five working days and that the contractor will obtain all required permits.
540 words, about 3 min