HVAC Ductwork, Air Handling & Mechanical Products calculator

AHU Coil Leak and Drain Test Pass Rate Calculator

Coil leak testing verifies that chilled water, hot water, or refrigerant coils do not have tube, header, or connection leaks before they are installed in an air handling unit. Tests may include pneumatic pressure testing (typically 150 to 300 psi depending on design pressure and coil type), hydrostatic testing, or helium leak testing for critical applications. Drain pan testing confirms that the condensate drain pan is watertight and drains correctly at the specified slope. Tracking the percentage of coils that pass on first test helps identify when a brazing or tube expansion process is drifting before large numbers of coils are rejected.

What this calculator does

  • Calculate the coil leak test and drain pan test pass rate for chilled water, hot water, or DX coils in air handling unit production. Compare tested coils that pass to total coils tested and check the gap against your quality acceptance target.
  • Use this when tracking leak test acceptance rates on chilled water coils, hot water coils, or DX refrigerant coils during AHU assembly. Each coil must pass a hydrostatic or pneumatic pressure test before it is installed in the casing. Tracking the pass rate identifies trends in brazing quality, tube expansion consistency, or incoming coil defect rates from suppliers.
  • Turns coils that passed leak and drain test, total coils tested, acceptance pass rate target into a rate for coil drain rate in hvac ductwork, air handling and mechanical products.

Formula used

  • Coil test pass rate = coils passed รท total coils tested
  • Gap to target = target pass rate - calculated pass rate

Inputs explained

  • Coils that passed leak and drain test: undefined
  • Total coils tested: undefined
  • Acceptance pass rate target: undefined

How to use the result

  • Use it when coil drain rate in hvac ductwork, air handling and mechanical products is being reviewed against a KPI.
  • Trend matters more than a single snapshot; pull the result for the last several periods before you act.

Common questions

  • What does the coil drain rate calculator give me? Calculate the coil leak test and drain pan test pass rate for chilled water, hot water, or DX coils in air handling unit production. Compare tested coils that pass to total coils tested and check the gap against your quality acceptance target. You get a rate you can defend before quoting, scheduling, or sign-off.
  • What numbers should I focus on first? coils that passed leak and drain test, total coils tested, acceptance pass rate target usually move the rate most. Pull from measured hvac ductwork, air handling and mechanical products runs, supplier data, and recent quotes rather than memory.
  • What do I do with this number? Use the gap to target to prioritize the next hvac ductwork, air handling and mechanical products kaizen or corrective action.
  • What should I verify first? Confirm the counts came from the same time window and the same scope; mismatched scope is the most common error.

Last reviewed 2026-05-12.