ASE S7 Air Conditioning Systems & Controls (School Bus) case studies
ASE S7 Air Conditioning Systems & Controls (School Bus) · Put your knowledge to work in context.
The ASE S7 Air Conditioning Systems & Controls credential is a specialty certification for technicians who service climate-control systems on school buses. It sits within ASE's school bus certification series, which separates the unique demands of pupil-transport vehicles from general medium/heavy truck work. The ASE S7 Air Conditioning Systems & Controls (School Bus) case studies are 5 cases and about 2,210 words.
1School Bus A/C Blows Warm on the Road but Cold at Idle
A 2016 conventional school bus with a rear roof-mount evaporator unit uses R-134a. The driver reports that vent temperature is 44°F at idle in the lot but climbs to 62°F at highway speed on a 95°F day.
449 words, about 2 min2Recovery Machine Shows Less Refrigerant Than Expected on a Retrofitted Bus
You are servicing a 2012 school bus whose A/C system was converted from R-12 to R-134a years ago. The under-hood label is faded; the only legible text says 'R-134a, 4.5 lb charge.' You connect a recovery/recycling machine with a new filter-drier and calibrated scale.
414 words, about 2 min3Compressor Clutch Chatters and Blows the A/C Fuse
A 2018 transit-style school bus with a 12V electrical system and a single belt-driven compressor has an A/C complaint: the 15A A/C clutch fuse blows intermittently, usually within 5–10 minutes of operation on hot days. The clutch coil resistance measures 3.6 ohms cold and 4.1 ohms hot (spec 3.2–4.0 ohms).
444 words, about 2 min4Rear Evaporator Frosts While Front Stays Warm
A 2019 school bus has a dual evaporator system: front dash unit and rear roof unit, both fed from a single compressor through a receiver-drier and a manifold that splits liquid to two TXVs. Complaint: rear vents blow 40°F and the rear evaporator ices over after 20 minutes, while front vents stay at 58°F.
438 words, about 2 min5Defroster Fails Inspection Because of Blend Door and Coolant Flow
A 2015 school bus fails a state inspection because the windshield defroster does not clear a 6-inch circle within the required time on a 30°F morning. The driver says heat is 'lukewarm at best' and the defroster only works when the bus is moving.
465 words, about 2 min