IMC 1203.4

IMC 1104.1

Suction line (large line) must be insulated to prevent condensation and maintain efficiency. Uninsulated lines lose capacity and drip moisture causing water damage.

IMC 1105 / ASHRAE 15

This is correct. ASHRAE 15 and IMC require refrigerant leak detection in mechanical rooms when the refrigerant charge exceeds certain thresholds. R-410A is heavier than air, so the detector at 12" above floor is properly placed. The alarm and exhaust fan activation are required safety responses. Annual calibration meets the standard.

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 / ASHRAE

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.

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.