IMC 307.2 / ASHRAE
What it means on the job
CRAH condensate drains must have a P-trap to prevent pressurized under-floor air from blowing back through the drain line. Without a trap, the raised floor plenum pressure will force air through the drain, preventing condensate from draining and potentially causing water damage.
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Related IMC sections
IMC 1203.4
Dissimilar metals (steel to copper) require dielectric unions to prevent galvanic corrosion. Without them, the pipe joint will corrode and fail within 2-5 years.
IMC 304 / Manufacturer Specs
The installation meets the manufacturer's minimum clearances. Equipment clearances are determined by the manufacturer's listing and installation instructions, which are enforced by code. As long as the actual clearances meet or exceed the listed minimums, the installation is compliant.
IMC 304.1 / Manufacturer installation instructions
While the height and distance from the register are acceptable, direct sunlight on a thermostat causes false high temperature readings, making the AC run excessively. Thermostats must be installed away from direct sunlight, heat sources, supply registers (min 3' is borderline), and exterior walls. The sunlight exposure is the primary violation here.
IMC 307.2.2
This is a proper installation. When gravity drainage is not possible, condensate pumps are an accepted solution. The key requirement is the overflow safety switch — if the pump fails, the unit must shut down to prevent water damage. Discharge to a laundry sink is an approved indirect waste receptor.
IMC 401.5
Outdoor air intakes and return air openings must have corrosion-resistant screens (min 1/4" mesh) to prevent entry of birds, rodents, and large debris.
IMC 501.3
Mechanical exhaust must discharge to the outdoors, not into an attic or other concealed space, to avoid dumping moisture and contaminants into the structure.
CraftIQ explanations are original educational commentary written in trade language and verified against the cited standards. Always confirm requirements against the code edition adopted by your jurisdiction — this is training material, not a substitute for the code book or your AHJ.