Any HVAC installers?

[WilliamM2]

I just had a new furnace and central air installed. My question is about the condensate drain which the installer said was supposed to be left uncapped. Everything I read says it should be capped. Air is always blowing out of it when the A/C is on, and I am also getting just a couple drips of water (see third pic) next to the outlet. I wondered if this could be caused by the air constantly blowing out the top the drain. The drain pan under the A coil is draining fine, and not anywhere near full, almost empty. So I can't figure out why water would run down there?

 

[Greenman]

I would think it should be capped. There is a trap in the line to stop air flow, having the top side open makes no sense at all.

I'm not sure where that condensation is coming from, is that also what's causing the puddle around the flue pipe?

It also looks like the coil box isn't sealed to the plenum.

 

[WilliamM2]

There's no puddle around the flue pipe, that's a grey fitting that the air intake for the furnace goes into. And the box is sealed, there's a flange about an inch back from the front, and he put a nice beat of silicone all the way around.

 

[boomerang]

I see no reason why it can't be capped. Mine are at both residences. Buy a PVC cap and put it on. No need to glue it. At our second floor condo the cap is removable and as part of their service procedure they pour some magic potion they have down it to clean out whatever biological nasties could be growing in it that could potentially plug it up. A blockage on our level could end up being a problem for both ourselves and the owner below so it's important to keep it flowing free.

As far as your leak, if the few drops are a problem, that warrants a call to them to correct their workmanship. Only you can decide if it's worth fixing.

In your second pic, the horizontal pipe appears to be running uphill from right to left instead of being sloped down. I doubt that is the cause of your leak as I can't imagine the water level rising high enough to cause the leak where you have it, but I suppose it's possible.

Disclaimer: I'm not an HVAC installer.

 

[drnickriviera]

I've always capped mine, but i could see why they would say not to. It would be possible for air pressure to blow the water out of the trap.

Unless that unit is in conditioned space, they need to do some sealing. The area around the condensate drain connection is probably gushing air. Cold air coming out is probably causing condensation there. That needs to be sealed with mastic, mastic tape, foil tape, whatever. Same with the joint between the coil and furnace. Also up higher where the refrigerant lines enter. There is usually a rubber grommet, but that usually doesn't seal it. Basically you shouldn't feel any air leaking out

 

[twinrider1]

I think it's a bigger problem than capped or not capped. I think the vent should be AFTER the p-trap. What he has as a vent is a good spot for a clean out, and yes that should be capped. But I think they also need to add a vent pipe after the trap. Look at the paperwork for your system for an installation diagram.

I'm not a pro, just a homeowner, but a vent before the trap makes no sense to me.

 

[pmark]

I just had a new furnace and central air installed. My question is about the condensate drain which the installer said was supposed to be left uncapped. Everything I read says it should be capped. Air is always blowing out of it when the A/C is on, and I am also getting just a couple drips of water (see third pic) next to the outlet. I wondered if this could be caused by the air constantly blowing out the top the drain. The drain pan under the A coil is draining fine, and not anywhere near full, almost empty. So I can't figure out why water would run down there?

Hi WilliamM2, quick question, in your third pic, there is a green plug next to the PVC drain pipe. Did your installer put that there or did you do it? I recently had Central air put in and my installer didn't plug this hole and cool air is blowing out of it. I assume it is safe to plug but I just want to make sure.

Thanks!

 

[drnickriviera]

Hi WilliamM2, quick question, in your third pic, there is a green plug next to the PVC drain pipe. Did your installer put that there or did you do it? I recently had Central air put in and my installer didn't plug this hole and cool air is blowing out of it. I assume it is safe to plug but I just want to make sure.

Thanks!

You will see a P and S on the case. That is Primary and Secondary drain for the pan. The secondary is a little higher than primary. You can connect a sensor to the secondary or plumb it to a location that can be easily seen. That way if you see water coming out of it, you know the primary line is plugged. Most don't bother with it and plug it.

 

[WilliamM2]

I've always capped mine, but i could see why they would say not to. It would be possible for air pressure to blow the water out of the trap.

Unless that unit is in conditioned space, they need to do some sealing. The area around the condensate drain connection is probably gushing air. Cold air coming out is probably causing condensation there. That needs to be sealed with mastic, mastic tape, foil tape, whatever. Same with the joint between the coil and furnace. Also up higher where the refrigerant lines enter. There is usually a rubber grommet, but that usually doesn't seal it. Basically you shouldn't feel any air leaking out

The coil box is sealed, it's about an inch under that gap. It's designed to fit together with that furnace. I can't get a picture of it, but it has silicone all the way around it, and is leaking no air.

The system designer is here this morning looking at all the work, he's going to have a tech come out and check the leak. He also says that the cap should stay off, I know he's wrong, I found it in the Trane instructions.

The unit is in the basement, in conditioned space.

 

[paperfist]

I would think it should be capped. There is a trap in the line to stop air flow, having the top side open makes no sense at all.

I'm not sure where that condensation is coming from, is that also what's causing the puddle around the flue pipe?

It also looks like the coil box isn't sealed to the plenum.

Mines capped. Wouldn't want anything to fall in there.

The switch is suppose to have the red emergency cover on it too, right?

 

[shabby]

Mine is uncapped.

 

[Greenman]

Mines capped. Wouldn't want anything to fall in there.

The switch is suppose to have the red emergency cover on it too, right?

I don't know. Around here we put the furnace on an SSU and hard wire it.

 

[TheBigEarl]

That stub up should have a cap on it. It shouldn't be glued on, but should be tight enough so as to not get blown off by the fan pressure in the coil. Its not there as a vent, its there to provide a way to cleanout the drain line if it gets clogged. If you don't cap it, air will always blow out it (since it looks like you have a blow through coil) and will be a huge waste of energy. To vent the trap, it should be on the downstream side of the tee. But the way they have it is 100% wrong.

Here is a detail of the way it should be done

 

[edro]

Mine is also uncapped.

 

[WilliamM2]

Tech came out yesterday. The leak was caused by condensation on one of the pipes in the a-coil that was pressed up against the foil covered insulation on the door, and it would run down the insulation. After messing with the door a bit, he didn't fix the leak, but did manage to break the little black plastic cover in pic two, and strip one of the screws on the door. Of course he told me none of this, I noticed it after he left.

So one angry phone call later, and they sent out the install manager today. He capped the pipe, replaced the cover, and put some type on insulation around that pipe and one or two others, per Trane tech support. Apparently this is a known issue after a design change. It appears everything is fixed, I only ran it for an hour (cold front came through today, only 64f), but no leak.

Supposed to be back in the upper 80's tomorrow, so I can test further, but even this morning before he fixed it, a drop appeared in less that 5 minutes, so I think it's good.

That stub up should have a cap on it. It shouldn't be glued on, but should be tight enough so as to not get blown off by the fan pressure in the coil. Its not there as a vent, its there to provide a way to cleanout the drain line if it gets clogged. If you don't cap it, air will always blow out it (since it looks like you have a blow through coil) and will be a huge waste of energy. To vent the trap, it should be on the downstream side of the tee. But the way they have it is 100% wrong.

Here is a detail of the way it should be done

Right, it's just a clean out. A vent on the other side of the trap is not required if the drain is under a certain length, this one is only about 3.5 feet, and goes staight down into a condensate pump.

 

[paperfist]

Tech came out yesterday. The leak was caused by condensation on one of the pipes in the a-coil that was pressed up against the foil covered insulation on the door, and it would run down the insulation. After messing with the door a bit, he didn't fix the leak, but did manage to break the little black plastic cover in pic two, and strip one of the screws on the door. Of course he told me none of this, I noticed it after he left.

So one angry phone call later, and they sent out the install manager today. He capped the pipe, replaced the cover, and put some type on insulation around that pipe and one or two others, per Trane tech support. Apparently this is a known issue after a design change. It appears everything is fixed, I only ran it for an hour (cold front came through today, only 64f), but no leak.

Supposed to be back in the upper 80's tomorrow, so I can test further, but even this morning before he fixed it, a drop appeared in less that 5 minutes, so I think it's good.





Right, it's just a clean out. A vent on the other side of the trap is not required if the drain is under a certain length, this one is only about 3.5 feet, and goes staight down into a condensate pump.

Did they seal that gap under the coil box like Greenman pointed out?

 

[WilliamM2]

Did they seal that gap under the coil box like Greenman pointed out?

I have mentioned three times now that the coil box is sealed, always has been. The seal is about an inch back from the front of the coil box. If they sealed it where Greenman thinks it needs sealing, the door would no longer be removable for service.

If you look at the first pic, you can see from the side where the seal actually ends on the side, and at that point goes across the front. There is no air leaking from the front.