IA HVAC case studies
IA HVAC · Put your knowledge to work in context.
The IA HVAC credential is aimed at irrigation and landscape-water professionals who specify, install, or service the heating, ventilation, and air conditioning equipment that protects pumps, valves, controllers, and backflow assemblies from freezing, overheating, and condensation. It tests whether you can reason about a small mechanical room the way an irrigation designer reasons about hydraulic zones: psychrometrics, load calculation, heating and cooling equipment, air distribution and ventilation, controls and electrical safety, commissioning and troubleshooting, and the codes and efficiency rules that govern the work. The IA HVAC case studies are 5 cases and about 3,531 words.
1Mixed-Air Humidity Complaint on a 5,000 cfm Air Handler
A 5,000 cfm built-up air handler serves an open-plan office. On a design day the return air measures 75°F dry-bulb and 63°F wet-bulb, while outdoor air is 95°F dry-bulb and 78°F wet-bulb.
687 words, about 3 min2High Superheat and Low Subcooling on an R-410A Rooftop Unit
A 3-ton R-410A rooftop unit with a thermostatic expansion valve and a single-circuit evaporator has run continuously on a 95°F day. The technician records 118 psig suction pressure and 62°F suction-line temperature, plus 300 psig liquid pressure and 95°F liquid-line temperature at the outdoor unit.
700 words, about 4 min3High External Static Pressure and Deficient Outdoor Air in a Small Office
A 2,000 cfm packaged rooftop unit serves a 1,500 ft² open office with a design occupancy of 25 people. The design external static pressure is 0.60 in.
730 words, about 4 min4Economizer Not Opening After an Actuator Replacement
A packaged rooftop unit with a dry-bulb economizer and enthalpy changeover serves a 2,000 ft² retail space. The unit has two compressors and a linked outdoor/return damper actuator.
719 words, about 4 min5Low Chilled-Water Delta-T in a Primary-Secondary Plant
A 400-ton water-cooled centrifugal chiller plant serves a university building through primary-secondary pumping. Design evaporator flow is 800 gpm, with 54°F return and 44°F supply.
695 words, about 3 min