The condensate shut off valve keeps filling up and shutting down system. Notice moisture at bottom and top of wood box.

At the end of the condensate line at the drain outside, nothing is draining so I've done the following each time it's shut down but to no avail:
1) Shop-vac at 4-5 times, so far.
2) Garden hose 3-5 second power flush followed by shop-vac.

At the beginning of the condensate line inside (see pics), I understand there are ways to do the following, which if apply to my situation, I'd appreciate your guidance:
1) Add bleach to condensate line.
2) "Blow-out" the condensate line.

Thanks!

 

I do not see the required p trap in your pictures.

 

Here is a side-view of the same area in the 2nd pic, instead of overhead, which I thought was the p-trap.

 

Here's a couple closer shots of front and side

 

I see someone "wrapped" the drain line. That's probably because without a trap, preferably at the air handler, there is cold air blowing out the drain line.

I would remove that "wrapping" and take some new pics.

Ultimately you'll want to be able to disconnect the line at the air handler for cleaning purposes.

 

When the evaporator coil is located before the blower motor the drain line is under negative pressure. This is usually the arrangement with air handlers.

The drain line will be unable to run water until the fan cycles off without a p-trap.

That picture does not look like a P-trap to me.
It almost looks like a drain for another appliance that is run near the AC drain.
Removing some insulation or using a dedicated camera may help verify this.

 

Thanks, that's all very helpful! It appears that I've opened up the clog, for now.
With that said, I won't have to use the a/c much in about 3 weeks. Hopefully, It'll keep draining throughout and I can plan on dealing with this issue in depth. Thanks again! To Be Continued...

 

Oops...Well. I guess that was pre-mature!

Exactly, what I noticed...It's draining but appears to only do so when the AUTO setting cycles off, then it drips out the drain outside. Did so all day yesterday but once the sun went down, the unit did not cycle on. Then, I could see water in auto shut-off capture area and coming through wood box again. From outside, I just did 3 more blasts of water with garden hose...Clear water came back out. No water in auto shut-off capture area and a/c has cycled on, again. Obviously, the issue appears to still not be resolved so the question I have now is...

What's wrong with the drain line will being unable to run water until the fan cycles off?

 

That was explained in post 6.

 

You may be able to correct this easily with a 3/4" 90 and a p-trap on the other side of that wall if it is outside.

If it isn't glued outside, you can remove the trap once per year to flush it out with a water hose.

I prefer 2 tees and a ball valve as shown in the picture.

 

Thanks!

FWIW, I have 2 separate units, installed in 2010. Before I bought the house in 2012, this same unit on the right flooded the garage. The original installer had to come out and fix it before the sale would be final...Apparently not!

I've attached a pic from the original pre-purchase home inspection before they "fixed it". To me, it looks like the unit on the right, which has the current issue, may have had a clean out and/or p-trap in the middle of the line running along side of the unit heading toward the back.

While, the unit on the left (no current issue) appears to have an UN-wrapped p-trap in the original inspection pic; either way, the start of the condensate lines on both units sure don't look the same now as they did pre "fix"...
BEFORE:
[ATTACH=CONFIG]56648[/ATTACH]

AFTER:
[ATTACH=CONFIG]56649[/ATTACH]

There's also a difference on the outside at the end of each condensate drain line.

Unit on right (current issue) end of drain is just a 90 attached to the end of the line, which is barely sticking out of the ground and apparently runs under the slab.
[ATTACH=CONFIG]56650[/ATTACH]

Unit on left (without current issue) end of drain runs directly from unit inside to the outside, parallel with and above the ground.
[ATTACH=CONFIG]56651[/ATTACH]

With all that being said...

1) Will I need to save and re-attach all of that wrapping to the drain line again?
2) Is THAT a p-trap at the end of the drain on the unit on left (without current issue) because, that one drains, when that unit is cycled on??
3) FWIW, materials are still under warranty for me with the original installer but NOT labor. Would you even bother calling them back out? If so, how UN-reasonable would it be to expect the original installer to actually fix it without me incurring their $100+ per hour labor charges?

 

Yes, kind of, the one with the upward pipe at the end served as a p-trap. not the type of p-trap we like to see, but it eliminates the negative pressure.

 

That P trap looks like it needs to be spun down so that it is shaped like a U.

Do these furnaces sit below grade level?

 

Thanks, what type do you like to see?

 

Thanks!
Like this?

[ATTACH=CONFIG]56686[/ATTACH]

These a/c air handlers sit on/above grade in the garage.

 

With that said, do I actually need a p-trap? The drain line on the unit with the current issue appears to run down under the foundation, then back up and outside above grade, which sounds like it would do the work of a P-trap.

 

I agree but it is very odd. If it doesn't drain well you may have something in the drain line preventing proper drainage. You may need to add at least 2 inches to that stub outside.

I wonder why they would have taken the drain under the slab?

 

It appears to drain well but still only when the unit is off. FWIW, I called installer, who confirmed "P-trap is the line running under the slab.". He also said "after you shop-vac water out of the end of line outside, go get a garden hose and re-fill the p-trap i.e. line under slab with with water through the clean-out.". I said, I don't see a clean-out and sent him pics...Waiting on reply.

To the ninety horizontally OR remove ninety and add a coupler then at least 2" to that stub vertically? And for what purpose?

Per installer... "Because that's where original drain line ran.".

 

May be there is a clean out opening somewhere inside the wall that you don't see, and that will generate negative pressure. If I were you, I build another p-trap near air handler so you can see and sure that you have a p-trap with no opening between p-trap and air handler.

 

I agree. A trap at the unit is the most reliable solution.

 

Thanks!
What type of trap would you use and where on unit?

 

Post #6 photo (p-trap B) is a good example. A should be covered in your case.

 

Thanks!
If I add a 2nd trap like that, at the unit, how will it affect this current issue on the trap running under the slab?

 

If you add a tee on each side of the new trap and only cap the tee between the new trap and the air handler it should drain fine. (One is a vent and one will serve as a cleanout).

Adding a $2 pvc valve between the tees and the air handler would help when cleaning the trap annually.

My shopping list would be a PTrap, two 3/4" tees, 2male adapters, 1 female thread pvc cap, a ball valve, primer, wet location pvc glue and a stick of 1 1/8" pipe insulation as well as some black duct tape and probably a piece of pvc pipe.

 

OK...Back at it!

Just a reminder, I've been advised by at least 2 local a/c pros, including the installers, that the unit in question already has a p-trap. The p-trap is the part of the drain line that goes into the wall, runs under the slab then comes up and drains outside, just barely above ground. They have both told me that adding a 2nd p-trap, at the unit, is a BAD IDEA.

FWIW, I removed the insulation and took some new pics, to try and help you all help me. As you can see, that's SIX 90's, as the drain line avoids one capped hole, at the wall, which it's lined up with and instead goes down, then to the left, then back again to enter the wall, at a lower spot.

1) How would you get the drain line to the wall, more directly, other than using SIX 90's?
2) Where would pour cleaning liquids, to clean out...
A) The drain line?
B) The drain pan?

 

In the left picture there is no visible trap.
I'm not sure what we are looking at in the right picture.

That right angle fitting outside on the end of the pipe that you've shown in a previous picture is not a trap.

This what I've done on my unit. It's on the side just like where it would be on yours.
The Tee has a cap just sitting on it for easy removal.

 

Yes, I understand , there's no visible trap AND that the pipe I've shown is not a trap. What you're looking at, in the picture on the right is the back end of the piping, in the picture on the left, where the piping enters the wall to my house. It then goes down runs under the garage floor and up again, draining outside the house, just above ground...Thus, forming my non-visible p-trap, UNDER MY HOUSE. Therefore, adding a p-trap, next to the air handler, as you have been suggesting, would be adding a 2nd p-trap, which local pros have told me is a BAD IDEA.

Let's see if this helps explain. Imagine the blue rectangle is my garage floor that the air handler sits on and the square, on top, is my house. The red arrow is what you're looking at, in the picture on the right, where the piping goes into the wall of the house. Then imagine your T is the end of the my pipe, draining outside.

Obviously not to scale.

 

Perhaps these angles will help along with the pic on the right...


Back end of piping, which goes into wall, from side & overhead aka "pic on right".

 

Ok.... so here's an important question..... how much lower is the outside drain than where it exits the air handler ?

What you are saying is that the entire line under the slab is considered a trap. Yes that is correct but it's also a gigantic "hard to clean" trap and pretty hard to determine how effective.

The trap is supposed to go at the air handler and a continuous slope towards the exit.

In the picture.... the arrow points to where the bulk of clogs occur. It's all PVC there. Easy to cut and replace. I'd cut the drain line and remove it back to the air handler. Clean the drain opening and replace it. You could put a Tee in the line where you could pour in a little bleach to clean the line. When the line is disconnected from the air handler.... hook up a garden hose and blow out the drain line to outside.

 

Thanks!

The outside drain is about 19 inches lower, than where it exits the air handler.

Yes, that's what I'm saying and AGREED! That said, are we also in agreement that adding a 2nd trap, at the air handler, is not the answer?

I understand but IIWII. That said, on the back end, where it goes into the wall, I'm thinking something like this, to lose the last two 90s and the T going into the wall that's acting like a 90. Then, I can go directly to the piece sticking out of the wall. HOWEVER, the piece sticking out of the wall is screwed (and potentially screwed) into the T and it's not budging.



That's a pvc 90 screwed directly into the coil, at the red arrow, where the bulk of the clogs occur...Would you replace it with PVC or is there perhaps a bronze 90 that can be screwed into there, that might help more? Also, are you suggesting adding the T in the line where I could pour in a little bleach to clean the line, approximately, where the blue arrow is?

 

After further review, I'm thinking I need to re-pipe NOT into the wall behind the unit, but rather add a trap & clean out that I can work with because just getting to the wall, behind the unit is a PIA, let alone working back there.



One re-pipe option (see pics below), might be to add a trap & clean out, where the red arrow is, re-pipe down the front following the blue line, then drill a hole in exterior wall, next to where the end of an existing copper pipe goes thru the wall, to drain a/c outside, near where a/c currently drains.

A 2nd re-pipe option, might be to go the other way, either in front of or behind the unit on the left; following it's piping out and drilling a hole in the opposite exterior wall, to drain outside, next to where unit on left, currently drains. FWIW: Piping can only fit behind unit on left with NO insulation until out from behind unit.

Thoughts?



End of existing copper pipe going thru exterior wall

 

Pick the shortest most direct method. Use 3/4" PVC for the drain line.

 

Thanks!
A 2nd re-pipe option, would avoid drilling a hole in an exterior wall, by going the other way; in front of the unit on the left; following below it's existing drain line, around water heater, tying into existing drain line with a wye, along the wall leading outside to existing p-trap.

If I tie into unit on left's drain line, correct me, if I'm wrong but I believe I have 2 options for p-traps...Which is best?

1) Remove p-trap I'm testing (on right), tie into unit on left's drain line and use it's existing p-trap outside, for both units.

2) Remove existing p-trap outside, give each unit it's own p-trap next to it's air handler, like the trap I'm testing in 1st pic.

Testing p-trap (on right) to ensure pan is not clogged.


Wall leading outside


Existing p-trap outside

 

I would definitely go with option 2. Each unit with its own trap.

 

Thanks!
Cool, I was leaning that way...
FWIW, this is 1/2 piping leading into the wall for the "house trap", all other piping is 3/4"...
No wonder it keeps getting clogged.