MI HVAC case studies
MI HVAC · Put your knowledge to work in context.
The Michigan HVAC exam is a licensing assessment used by the state to evaluate whether a candidate has the technical and code knowledge expected of a mechanical contractor working in heating, cooling, and ventilation. It is aimed at people pursuing contractor-level licensure - typically experienced installers and technicians moving into business ownership, or contractors adding HVAC scope to an existing mechanical license - rather than at entry-level apprentices. The MI HVAC case studies are 5 cases and about 3,349 words.
1Condensing Furnace Retrofit in a Tight 1950s Ranch
A contractor is replacing a 100,000 Btuh natural-gas, 80% AFUE furnace in a 1,400 sq ft single-story ranch built in 1954 near Lansing. The existing unit vents into a 6-inch masonry chimney shared only by the furnace; the water heater is now power-vented separately.
716 words, about 4 min2Walk-in Cooler Not Holding Temperature in Summer
A restaurant walk-in cooler, 8 ft x 10 ft x 8 ft high, is served by a 1.5 HP medium-temperature condensing unit with a matching air-cooled evaporator. In July the box runs 44°F instead of the 38°F setpoint, and the compressor runs continuously.
656 words, about 3 min3Duct Sizing and Static Pressure in a Two-Story Retrofit
A contractor is adding a 600 sq ft finished basement to an existing two-story home with a single 80,000 Btuh furnace and a 3-ton AC. The existing trunk is 8x20 in sheet metal with six 6-inch branch runs.
689 words, about 3 min4Gas Piping, Combustion Air, and Venting for a Replacement Boiler
A contractor replaces an atmospheric natural-gas boiler in a basement mechanical room with a new 120,000 Btuh input atmospheric boiler. The room is 10 ft x 12 ft x 8 ft with a solid door and no louvers.
625 words, about 3 min5Permit Scope and Licensing on a Multi-Trade Residential Job
A Michigan HVAC contractor is hired to replace a furnace and AC, add a bathroom exhaust fan, and run a new gas line to a range in a single-family home. The contractor holds a mechanical contractor license but no plumbing license.
663 words, about 3 min