Is cold air pushing out of the evap coil case normal?

[chrisntam]

Here’s a pic, cold air is pushing out of both pvc vents and the copper penetrations in the case. It appears the penetrations have some sort of rubber bushing that gaskets the line, but you can see there are holes in them. Normal?

It's not a lot, but I was surprised to feel cold air coming through the pvc drain lines and the bushings...

[Robert Adams]

Here’s a pic, cold air is pushing out of both pvc vents and the copper penetrations in the case.  It appears the penetrations have some sort of rubber bushing that gaskets the line, but you can see there are holes in them. Normal?

It's not a lot, but I was surprised to feel cold air coming through the pvc drain lines and the bushings...

           The overflow has a tiny trap on it that should stop the airflow when it is full of water. Your drain doesn't have a trap which is why it has air coming out of the tall vent pipe. 

            Allot depends on where your unit is. If it's an upflow inside the house it isn't a big deal to loose a little air through it as that air is staying in the house. Similar for a basement. Now if it's in the attic that loss of air is not a good thing but... When you have a trap on the drain of a unit in an attic they tend to quickly fill up with moldy green and black goo because the attic is hot and there is water in the drain. 

         I like the idea of not loosing air through the drain pipe but having a trap in it can cause bigger issues when it plugs up like water leaking from the pan into the unit, through the ceiling etc... 

           The drain connection of the unit is 3/4 and too small. Always upsize it to 1" or bigger as that makes it harder for the mold to plug the drain and makes it easier to clean out.

[Roly]

           The overflow has a tiny trap on it that should stop the airflow when it is full of water. Your drain doesn't have a trap which is why it has air coming out of the tall vent pipe. 

            Allot depends on where your unit is. If it's an upflow inside the house it isn't a big deal to loose a little air through it as that air is staying in the house. Similar for a basement. Now if it's in the attic that loss of air is not a good thing but... When you have a trap on the drain of a unit in an attic they tend to quickly fill up with moldy green and black goo because the attic is hot and there is water in the drain. 

         I like the idea of not loosing air through the drain pipe but having a trap in it can cause bigger issues when it plugs up like water leaking from the pan into the unit, through the ceiling etc... 

           The drain connection of the unit is 3/4 and too small. Always upsize it to 1" or bigger as that makes it harder for the mold to plug the drain and makes it easier to clean out.

Would a Studer vent work on the vent pipe in this use ?  It will prevent outflow of cold air but allow suction from the attic for draining.  Roly

[Robert Adams]

Would a Studer vent work on the vent pipe in this use ?  It will prevent outflow of cold air but allow suction from the attic for draining.  Roly

    No need for the studor vent since it's not a plumbing vent so no noxious gasses. You should have a trap then that vertical vent then the pipe will usually drain into a stand pipe like a washer or there is also a way to drain it into a sink trap. So the trap on the unit just keeps the air from blowing out and the vent lets the water run to whatever trap it's dumping into next. 

    The sink drain option is often done on units mounted in attics. They tend to have issues and plug up. Personally I would like to dump our water and the excess from the RO system out in the yard somehow. But don't have a good way to use the water once it's outside.

[chrisntam]

It’s a horizontal unit in the attic in Texas. It sounds like I can either have a little loss of air flow or a a potential for a clog. I’ll seal the other penetrations with silicone. Thanks!

[chrisntam]

I guess no reason to seal the small openings as the air that is escaping there will escape elsewhere...( through the vents)

[Philip1231]

You want one of these: its called an EZ Trap made specifically for HVAC applications:

[attachment=28238]

[Robert Adams]

You want one of these: its called an EZ Trap made specifically for HVAC applications:

 Yup those are awesome unfortunately when you go to the supply house here you get the dreaded blank stare if you ask for one. I wanted to put one on our unit but... It's an upflow and I don't have the room for it so mine just dumps into the standpipe and looses a little air into the closet. That little puff of air just keeps the 140* hot moist attic air from leaking in as fast around any gaps around the plenum and vent pipes.

     I can't wait to be done with the bathrooms in the house so I can finish sealing in the attic and adding a bunch of insulation. Our house has very little blown in mineralwool from the 1950s. That was nasty stuff back then with lots of sand like coalslag in it because quality was not a word they knew back then. So it's not easy to stay cool until that's all done considering you are fighting 120 to near 150* attic temps. Big delta T there. 


       Delta T is the fancy term that sciency people like to use to feel special. It just means difference or differential. I'm headed out on my boat with it's line, port and starboard and all those other words so I can feel special using more fancy words.