HVAC Condensate Drain Installation

This article is about HVAC Condensate Drain Installation as per International Codes and standards.

The evaporator drain pan shall have a trapped drain pipe, attached to the bottom or to the side of the drain pan, flush with the bottom plate.
“Condensate drain line shall be of corrosion-resistant type. (UMC Para 309.3)”
Condensate drain line (discharge piping) shall not be smaller than the drain pan connection. (UMC Para 309.3).
Drain pans shall extend completely under the coil sections and shall have minimum 1-¼ inch threaded drain connections for
AHUs with the total supply air equal to or greater than 5,000 cfm.
Drain pan shall be sloped toward drain connection.
Condensate drain line shall maintain a minimum horizontal slope in the direction of discharge not less than 1%. (UMC 309.3)
The drain pipe trap shall have a water seal height equal to or larger than the fan’s External Static Pressure (ESP) but not less than 50 mm (2″”).
Note: ESP can be read from the Construction drawings or Specifications”
The drain pipe shall discharge to the nearest floor drain
Exception: HVAC units installed outside of buildings may discharge condensate onto the ground or roof, but not onto walkways.

1-SAES-K-001 — Heating, Ventilating and Air Conditioning (HVAC).
2-SAES-K-100 — Saudi Aramco Mechanical (HVAC) Code.
3-Uniform Mechanical Code (UMC).

HVAC Condensate Drain Installation | HVAC Engineering