I recently got a new package unit installed to replace the 30-year-old one that came with the house. It works MUCH better than the old one, which had a slow leak and iced up regularly.

I noticed that the condensate drain drips straight out onto the pad. Should there be a trap here? Picture of drain

The round hole on the left has a standard pipe fitting inside, and currently it is just dripping straight down.

How bad is it to leave it like this? This Bryant system has the coils positioned before the blower, so presumably the drain is under suction when the unit is running. Fortunately, it doesn't run all the time.

  • I would have expected isolation pads between the base frame and the slab
    – Jasen
    Jul 29, 2020 at 1:34
  • For sound dampening? Might help a bit I guess. Fortunately, the new unit is massively quieter than the old one due to the condenser being stacked on top of the coil/compressor/heat exchanger section, instead of the compressor being right next to the house (old unit was more like a pancake). The duct connections are short, flexible connectors. I can't tell you how nice it is to finally have working A/C after all these years :) Jul 29, 2020 at 4:03
  • 1
    You're asking about a trap, but do you simply mean a drain tube extension?
    – isherwood
    Jul 29, 2020 at 14:32
  • mainly to stop the base from rubbing on the concrete and rusting out, but also to reduce vibrations it may have feet that are not visible from this angle.
    – Jasen
    Jul 29, 2020 at 21:28
  • 1
    I would leave it the way it is since it sounds like you followed the MFG instructions.
    – Ed Beal
    Aug 3, 2020 at 14:35

3 Answers 3


The drainage is normal and you want it to drain. Some units are quite sensitive to blockage and a trap will prevent the condensate from getting out. This drainage is quite normal.
I would not worry as just about every unit has a drain of some type - most just like yours.

  • Great to know, thanks! I was just worried about the drain getting clogged or stuffed full of something by a critter, but it's a good few inches off the ground, so I guess that's unlikely. Jul 29, 2020 at 4:03
  • I have had minor issues with insects when the unit is not run but not often as the times when the unit is not being used is usually cold and less critter activity when it’s cold.
    – Ed Beal
    Jul 29, 2020 at 13:25

You only need a trap if you're connecting directly to a different drain pipe

With no drain pipe no trap is needed. with an air gap no trap is needed.

  • It doesn't make it harder for the unit to drain? There's slight suction on the pipe as the coils are on the return side. Jul 29, 2020 at 3:42
  • 2
    You only need a trap when connecting to a sewer drain and this is to prevent the gasses from the sewer isolated. Air gap are usually on food storage coolers and freezers to prevent any migration bacteria laden moisture.
    – Ed Beal
    Jul 29, 2020 at 13:22
  • These things drain by gravity, There will only be suction on the pipe if it's full of water usually they don't produce condensate at a rate sufficient to fill the pipe.
    – Jasen
    Jul 31, 2020 at 2:31

Do you "need" a condensate trap - YES, unless your unit specifically comes equipped with an internal trap, you need one. Many package and split systems require the installation of a dedicated condensate disposal system, including a trap. Check your installation documentation. Bryants do have in some cases an internal trap.

2.) Either way, a trap is more than a drain. I quote here typical condensate trap information from a typical well known package unit manufacturer's install documentation.

"Do not operate unit without a drain trap. The Condensate drain is on the negative pressure side of the blower; thererfore, air being pulled through the condensate line will prevent positive drainage without a proper trap".

Yes, the bolds in this quote are from the manufacturer, not me.

Once you install the trap you must PRIME it to get it started. Do not depend on the condensate from the unit to prime it. Every minute your unit runs without a trap, or with an un-primed trap it is sucking warm outside air, dirt, bugs, mold, etc. right through the trap and right into your conditioned air space, because that entire circuit is "ON THE NEGATIVE PRESSURE SIDE OF THE BLOWER".

Most traps need about 3" lift to work correctly and allow for static pressure fluctuations.

Besides the dirt/mold/warm air/fiasco, your current situation is draining condensate onto the chassis of your unit. This will lead to corrosion - which you can already see forming a little in the picture, because condensate is water, and can also be slightly acidic.

Finally, did you not notice that your installer left your unit on the delivery skid when he installed it? Was this a deliberate choice or simply an oversight? (there might be reasons why it was left on the skid, I suppose, but it looks tacky)

  • Is this from chatgpt? Jul 28, 2023 at 19:53
  • I agrree with @RohitGupta. looks like chatgpt. Answer doesn't apply to ground units and no skid in picture, unit was installed on concrete pad
    – JACK
    Jul 28, 2023 at 22:52

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