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Condensate Drain Line Verification Checklist

Essential Checklist+

Complete these critical checks before approving the work or proceeding to the next construction stage.

✓14 Inspection Points
✓4 Verification Categories
✓Inputs & Sizing Method+
  • Confirmed whether this drain line serves a single unit only, or is manifolded (shares condensate flow) with other units
  • Cooling capacity (tons) confirmed against the equipment's nameplate or spec sheet — combined total of every unit sharing the line if manifolded
  • For a single unit, actual manufacturer-specified drain pan connection size checked against the spec sheet, not assumed to be exactly 3/4in
  • Static pressure entered is the MAXIMUM value AT THE DRAIN PAN itself (not a whole-system external static pressure reading), from actual equipment spec or a direct measurement, not left at the default
  • Coil/blower configuration (draw-through vs. blow-through) confirmed against the actual equipment, not left at the default
✓Design & Planning+
  • Selected drain pipe diameter checked against local plumbing/mechanical code amendments, not just the base IMC rules
  • Trap height cross-checked against the equipment manufacturer's own guidance for worst-case (dirty filter/dirty coil) static pressure, not just this calculator's planning-reference figure
  • On a manifolded line, confirmed that EACH unit's own drain pan is individually trapped — not relying on a single shared trap for multiple units, and this calculator rerun once per unit if their drain-pan pressures differ
  • If an overflow here could damage any building component, one of the four IMC 307.2.3 auxiliary protection options selected and included in the design
✓Installation+
  • Continuous slope maintained at or above the target rate for the entire run, with no sags, bellies, or backfalls
  • Pipe diameter never decreases from the drain pan connection to the final disposal point
  • Trap installed at the design height (H) with the correct outlet-leg dimension for the equipment's actual configuration (draw-through vs. blow-through)
  • Drain line terminates at an approved, visible/accessible point (floor drain, condensate pump reservoir, or approved exterior location) — never connected directly into a sanitary drain/vent without an approved air-gap fitting
✓After Installation+
  • Trap and full line flushed with water and visually confirmed to drain freely with no leaks, before closing up any concealed spaces
Full QC Checklist+

Verify inputs/sizing method, design and planning, installation, and post-installation verification for an HVAC condensate drain line.

✓24 Inspection Points
✓4 Verification Categories
✓Inputs & Sizing Method+
  • Confirmed whether this drain line serves a single unit only, or is manifolded (shares condensate flow) with other units
  • Cooling capacity (tons) confirmed against the equipment's nameplate or spec sheet — combined total of every unit sharing the line if manifolded
  • For a single unit, actual manufacturer-specified drain pan connection size checked against the spec sheet, not assumed to be exactly 3/4in
  • Load/climate condition selected honestly for the installation's actual humidity exposure, not left at the default
  • Static pressure entered is the MAXIMUM value AT THE DRAIN PAN itself (not a whole-system external static pressure reading), from actual equipment spec or a direct measurement, not left at the default
  • Coil/blower configuration (draw-through vs. blow-through) confirmed against the actual equipment, not left at the default
  • Horizontal drain run length measured from an as-built or planned routing drawing, not guessed
  • Slope target (code minimum vs. recommended) chosen deliberately based on available headroom, not automatically
✓Design & Planning+
  • Selected drain pipe diameter checked against local plumbing/mechanical code amendments, not just the base IMC rules
  • Pipe material confirmed to comply with locally-approved materials (typically rigid PVC/CPVC), pressure/temperature rated for the equipment
  • Trap height cross-checked against the equipment manufacturer's own guidance for worst-case (dirty filter/dirty coil) static pressure, not just this calculator's planning-reference figure
  • On a manifolded line, confirmed that EACH unit's own drain pan is individually trapped — not relying on a single shared trap for multiple units, and this calculator rerun once per unit if their drain-pan pressures differ
  • If an overflow here could damage any building component, one of the four IMC 307.2.3 auxiliary protection options selected and included in the design
  • Cleanout access planned at every change of direction along the drain run
✓Installation+
  • Continuous slope maintained at or above the target rate for the entire run, with no sags, bellies, or backfalls
  • Pipe diameter never decreases from the drain pan connection to the final disposal point
  • Trap installed at the design height (H) with the correct outlet-leg dimension for the equipment's actual configuration (draw-through vs. blow-through)
  • Drain line terminates at an approved, visible/accessible point (floor drain, condensate pump reservoir, or approved exterior location) — never connected directly into a sanitary drain/vent without an approved air-gap fitting
  • If a condensate pump is used, its reservoir capacity and float switch are adequate for this calculator's estimated GPH, with a visible or audible high-water alarm
✓After Installation+
  • Trap and full line flushed with water and visually confirmed to drain freely with no leaks, before closing up any concealed spaces
  • Auxiliary pan/float switch (if installed) function-tested by manually raising the water level to confirm shutdown or alarm activation
  • No standing water or visible biological growth in the drain pan or accessible sections of the line during initial operation
  • Drain line insulated where it passes through conditioned or unconditioned humid spaces, if exterior condensation on the pipe itself is a concern
  • Maintenance schedule established (periodic trap/line flushing, algae inhibitor tablets where used) rather than treated as a one-time installation task
Inspection Notes+
Use the latest approved drawings, specifications, and site measurements.
Complete all critical checks before proceeding to the next work stage.
Record deviations and confirm rectification where required.

Related Calculators & Guides

Condensate Drain Line CalculatorOpen the related calculator and verify the current project inputs.

FAQ

Use it after collecting the project inputs and again before approving or closing the relevant work stage.
No. It supports verification but does not replace approved drawings, specifications, codes, manufacturer requirements, or professional inspection.