To trap or not to trap condensate drain on a package unit? - Contractor Talk - Professional Construction and Remodeling Forum

Electric_Light · 07-17-2009, 07:31 PM

On the same roof top, I see some units with a straight reversed L pipe and some units with traps.

The water in trap keeps the indoor air from flowing out, but water always remains at the level of the pipe and keeps stagnant water in the condensate pan and promote corrosion...

NickTech · 07-18-2009, 07:28 PM

Quote:

Originally Posted by Electric_Light

On the same roof top, I see some units with a straight reversed L pipe and some units with traps.

The water in trap keeps the indoor air from flowing out, but water always remains at the level of the pipe and keeps stagnant water in the condensate pan and promote corrosion...

on package systems the blower is in front of the coil, placing the coil and drain pan under a negative pressure. the suction will draw outside air in through the drain not only adding to the load, but more importantly draws a mass of air through the drain pulling the drain water away. this allows for the pan to overflow. installing a trap will block the air from pulling the drain water away from the drain. as long as condensate is being removed then the water in the trap wont be stagnant.

MechAcc · 07-19-2009, 08:23 AM

Here are some links to articles on condensate traps. Some will download pdf files. The articles point out problems with incorrect trapping.

Condensate Traps Jan 1, 2001 HPAC Engineering

Web Site video page for Cost Gard Traps on different trap problems Go to the bottom of the page for the videos. Cost Gard is the drain trap specified by WalMart and Walgreen Stores. An expensive drain to purchase but will pay for itself by preventing water damage. The last couple of videos show the Cost Gard installed.

Condensate Trapping Don’t Get Caught in a Trap of Your Own.

ASHI Reporter article “Let’s Concentrate on Condensate”

trout lake · 07-19-2009, 04:18 PM

Nicktech is bang on!

coolmen · 07-20-2009, 01:11 PM

Quote:

Originally Posted by NickTech

on package systems the blower is in front of the coil, placing the coil and drain pan under a negative pressure. the suction will draw outside air in through the drain not only adding to the load, but more importantly draws a mass of air through the drain pulling the drain water away. this allows for the pan to overflow. installing a trap will block the air from pulling the drain water away from the drain. as long as condensate is being removed then the water in the trap wont be stagnant.

thats what I was gonna say

)

sparky_123 · 07-22-2009, 10:02 PM

trap is a must, i like to put a lttle bleach in drain pan once a year keeps crap from building up

flashheatingand · 07-25-2009, 01:38 PM

Trapping is the easy part. It's going into the crawl space to make sure that the condensate line is graded right that gets neglected. Frequently when under the house, I see that the condensate run is messed up.