How to remove return duct on A/C? Advisable DIY?

[CookingWithGas]

I have a York furnace/AC unit. There is water puddling from underneath, which appears to be an issue with a clogged floor drain (I am assuming that condensation is not draining properly, can't imagine why else water would be involved). The floor drain is underneath where the return duct attaches to the blower unit, so the return assembly has to be moved. The return unit is screwed on to the blower unit, easy enough. But a duct comes down from the ceiling and attaches to the lower part, and needs to get disconnected to be able to move the whole thing off the drain. The downward duct seems to be attached only by some sort of crimping, no fasteners evident. How do I get this apart?

Any advice on this? I can provide photos if helpful.

[Snnipe 70E]

I have a York furnace/AC unit. There is water puddling from underneath, which appears to be an issue with a clogged floor drain (I am assuming that condensation is not draining properly, can't imagine why else water would be involved). The floor drain is underneath where the return duct attaches to the blower unit, so the return assembly has to be moved. The return unit is screwed on to the blower unit, easy enough. But a duct comes down from the ceiling and attaches to the lower part, and needs to get disconnected to be able to move the whole thing off the drain. The downward duct seems to be attached only by some sort of crimping, no fasteners evident. How do I get this apart?

Any advice on this? I can provide photos if helpful.

The return should be Taped and sheet metal screws connecting it.
Pictures yes.

Are there any tin knockers here?

[TriPolar]

It is either just force fit with the crimped connection, or there will be a sheet metal screw or two in the joint. Occasionally a pop rivet. If it doesn't pull apart, remove the screws or rivet and try again. I'm not sure if you are talking about the joint at the furnace, or one up above somewhere. Either way it sounds like you have to push up on the pipe to get it disconnected. Their should be enough give, because they got it in there somehow. If the next joint up is in the ceiling somewhere, be careful. The joint may be wrapped with some old tape or something that could break off and clog the duct when you reassemble. That would be a poor installation. Also, find a way to hold the pipe up in the air before you disconnect it so that it doesn't drop out of another joint somewhere above. That connection is guaranteed to be hidden somewhere.

[CookingWithGas]

Photos (http://www.seiglefamily.com/data/duct.html) showing overall system, close up of connection from return to blower, and return duct to return. Problematic connection is from the vertical duct down to the box that holds the filter.

[Joey P]

So there's a floor drain under the unit somewhere? Are you [i]sure[i] said drain is under the return section? Can you get a flashlight and just see what's going on under there? Might just be a towel or something backing up the drain. Could be dirt and muck that you could reach under and poke out with a hanger (straighten out and put a small 90 degree bend at the end of it).

Something else you could try, assuming that's where the drain is and you can't see a problem. Dump a bucket of water under it (slowly) and see if it pools up or goes down the drain. If it goes down the drain, then that's not the problem.

My WAG is that your drain pipe is clogged. The water is backing up into the evap unit and spilling over somewhere. There should be an access panel somewhere in the plenum that you could remove and take a look. You could also unscrew that little red plug and see if water spills out (it shouldn't under normal circumstances).

BTW, I think removing that box with the filter in it is going to be a bigger PITA that it appears.

[Joey P]

The other reason water could be involved is if your April-Aire is leaking.

ETA, as for how to get those off...They slide off. It's kind of hard to explain If you can imagine, the two parts that each have a fold at the end of them, if sorta kinda looks like the ...ummm, lets see. Okay, how about this, imagine two pieces of metal shaped like this ][ now imagine a third piece shaped like a C that slides over the top of those brackets. No, that's not clear.
Ummm, yeah, they slide off. Let me see if I can find a diagram somewhere.

[TriPolar]

OK, you're talking about the rectangular duct on the right I assume. Looks like a folded flange or relief at the bottom, that may be covering screws underneath. Stick a flat head screwdriver in there to see if will pull back and reveal screws. Can't tell what's happening at the top, looks like a large round duct going out to the right.
It looks like it was built up from the bottom in place though, so I'd look at disconnecting the duct work at the top, and unscrewing the box where it joins the main unit by the filter. Then move the whole stack. It sounds like you have to take that box out anyway.

[TriPolar]

The other reason water could be involved is if your April-Aire is leaking.

ETA, as for how to get those off...They slide off. It's kind of hard to explain If you can imagine, the two parts that each have a fold at the end of them, if sorta kinda looks like the ...ummm, lets see. Okay, how about this, imagine two pieces of metal shaped like this ][ now imagine a third piece shaped like a C that slides over the top of those brackets. No, that's not clear.
Ummm, yeah, they slide off. Let me see if I can find a diagram somewhere.

I thought it might be that. Didn't know what it was called, or how to describe it either.

[Joey P]

Here's (http://www.marstaninc.com/rec_sheet_metal.html) a few different styles, but all the same idea. That exposed part at the connections should slide off. Often times you have to unbend a part at the edge and put a lot of muscle into it, but this is typically how it's done.
Personally, I'd see what I could do without removing that, it's a PITA.

[Joey P]

Okay, I didn't notice the other pictures at the bottom. If you really want to seperate the box from the return duct what you'll do is...
Starting with the short sides, the metal strip has a flap bent around the corner. Straighten them. Now grab that flap with a pliers and pull it. The strip will slide off. It'll probably take some muscle. Also, it's usually a tight fit so it'll probably bind up a few times, muscle through it, you might need to push and pull on the ductwork and the box while pulling to get it to slide off. Do the same thing on the other short side. The two long sides are the same, they just won't have those flaps. Then unscrew the zip screws from the furnace and the box will come off. Make sure that the return duct is secured so it doesn't drop. If it drops it could bend any horizontal sections of the ductwork that are attached to the ceiling. It wouldn't hurt to have an extra set of hands available.

Look at the picture in my link directly above the words "Drive slip or cleat (a)" That's a cross section of what you're working on. You're going to slide that top dark black part off.

But, again, this is a PITA project. It's certainly doable, but I'd consider it a last resort if you really can't get at the floor drain by other means.

[TriPolar]

Here's (http://www.marstaninc.com/rec_sheet_metal.html) a few different styles, but all the same idea. That exposed part at the connections should slide off. Often times you have to unbend a part at the edge and put a lot of muscle into it, but this is typically how it's done.
Personally, I'd see what I could do without removing that, it's a PITA.

I didn't see your link before, finally found cleats in the McMaster-Carr catalog. I helped somebody try to take those off a joint. The first side moved about an inch and stuck solid. He bent the end around, wrapped it with tape and gave up.

But you've got a better point. Why would a drain be underneath the unit in the first place?

[Joey P]

I didn't see your link before, finally found cleats in the McMaster-Carr catalog. I helped somebody try to take those off a joint. The first side moved about an inch and stuck solid. He bent the end around, wrapped it with tape and gave up.
Like I said, PITA, and it should be a last resort. The bind up so much, you feel like you're going to rip all the duct work right out of the walls trying to remove them.


But you've got a better point. Why would a drain be underneath the unit in the first place?
Sometimes that's just the way houses come together. Sometimes the person who put in the furnace assumed his buddy would run the return duct right along side the plenum instead of 8 inches away or a hundred other reasons, but that's neither here nor there.

Seriously, before you try to dismantle the ductwork, just take a look under it with a flashlight. There certainly appears to be plenty of clearance to get in there and deal with any problem that's on the surface. If there's a genuine clog that to far below grade, then you can worry about moving things.

[Melkor28]

Looks like a " Slip and Drive" connection, I see no screws. The long sides will be slip, no problem; the short sides will be the drive connection , a little tricky. Too remove the vertical piece off duct: Look at the short side of the connection, see the 1", of what looks like a flat band ( Drive), wrapped over onto the long side; unfold this. Pry with a screwdriver, then with a vise grip. Do it for both sides. Then vise grip on the left 1" flap you just unfolded; hammer the vise grip horizontally right to left, to drive the "drive" off the left hand side. Repeat for the other side of duct, then the top connection. The vertical duct should slide towards you, relative easily. Then remove the horizontal piece, should be intuitive. The sheet metal screws will a 5/16" hex head; adapters for drill at Home Depo. You probably destroy the "drives" removing them. I usually just rip them out and use new ones on re-install. Drive material ..another trip to Home Depo. To reinstall... After putting the horizontal piece back in, slide the vertical piece back in, The flat on the long sides, going into the "slip". Then cut a new length of " drive" 3" longer than the short side. make a 1 1/2" bend on one end of the drive, start the other end of the drive on the "ears" of the connection. The ears are the the little folds on the short side of the duct connection. Joey P as a good link with connections. Hit the 1 1/2" fold of the drive towards the duct, until the drive is all the way on. You will have 1 1/2 " extra sticking off the other side of the duct , hammer this over flat on the long side of the connection. Repeat for the other side, then the top connection. Good luck.
If this sounds too complicated, call a HVAC guy.

Tinknocker here. L.U. 28 NYC Sheet Metal Worker

[CookingWithGas]

First thing I did was check underneath with a flashlight. There are two drain pipes that end underneath, and there's a puddle there, so I'm assuming it's a clogged drain. Can't actually see the drain because of the water. One comes from the front of the unit. It is visible in the first photo coming from the front, taking an immediate turn to run down the left side. Unseen in the photo is that at floor level it bends again around the back then ends underneath the unit. The April-Aire humidifier unit has a plastic runoff hose that drains into this pipe, but the supply line valve is turned off (it's summer) and there is no water draining from the runoff hose, so this is not the problem.

The other drain pipe is also visible in the top photo, between the blower and the return duct on the rear wall. It also takes a bend at the bottom to terminate under the unit. The position of this pipe in the photo shows you exactly where it appears that the drain is.

I will try the easy thing first which is to clear the drain with a wire or something.

[Joey P]

Puddle pooling up at the drain is a good sign. It means (well, it implies anyways) that there isn't a clog in any drain hoses, it also tells us that you can at least see what's going on down there. If you can see it, you can probably get something under there and pick at it. If there's a grate over the drain then my guess is either there's a towel or something completely blocking the drain or all the little holes are filled in with dust/dirt/slime/general muck. A few pokes with a wire and the water will probably start draining. Once it's all down and you can see what you're doing you can poke out the rest of the holes.

Then, make a note to yourself, write it on your calender, set an alarm on your phone, do something....to make sure that once in a while you stick your head under there and take a look at it. Maybe it should be part of what you do when you change the furnace filter.

ETA, regarding the April-Aire, I assumed it wasn't running since it's August, but the water line leading to it could be leaking. I just mentioned it because it was another source of water.

[CookingWithGas]

Once I unscrewed the return from the blower unit, there was enough flex to get to the drain without having to disconnect the duct. The drain is just underneath the edge of the unit.

I suctioned out as much water as possible with a shop vac but the pipe has a right angle about 6-8" down.

I am going to assume that trying a liquid drain cleaner (like Drano) is a bad idea. I suspect that this drains into the sump, and would pump out into my yard.

Next step is a stiff wire for exploratory surgery then maybe a snake if that's what it takes.

Puddle pooling up at the drain is a good sign. It means (well, it implies anyways) that there isn't a clog in any drain hoses, it also tells us that you can at least see what's going on down there. If you can see it, you can probably get something under there and pick at it. If there's a grate over the drain then my guess is either there's a towel or something completely blocking the drain or all the little holes are filled in with dust/dirt/slime/general muck. A few pokes with a wire and the water will probably start draining. Once it's all down and you can see what you're doing you can poke out the rest of the holes.

There is no grate. The pipe end is flush with the surface of the concrete. The cause of the clog is not visible.

[CookingWithGas]

Yet another update. I poked a wire down as far as I could, which was only about 12-15". To see if anything I had done cleared the clog, I poured water into the drain. Once the water was about 4" below grade, it didn't continue to get higher as I poured more in, so maybe the clog is cleared. I dumped some pretty nasty-looking shit out of my shop vac, lots of dirt and some other white translucent gel-looking stuff.

[Joey P]

The drain shouldn't go to your sump, it should be connected to your sanitary sewer and go out to the street.

Do you have mice in your basement at all? Maybe a few have fallen in?
Kids? Could someone have let a ball roll under there?
Has your basement ever flooded? I've have neighbors who had just a little water entering between the floor and the foundation, but it was enough to carry a towel over to the floor drain and plug it up.

Your next option is probably to try either a plunger or a snake and see if you can push the clog out or pull it back in. If you can't do it easily, you may want to consider calling in a plumber. The problem I'd worry about is pushing the clog to far and having it back up the rest of your house.

ETA, looks like your good. The water should sit a few inches below the level of the floor. Could you tell what you sucked up? Was it just general nastiness or was there anything recognizable in there?

[CookingWithGas]

Do you have mice in your basement at all? Maybe a few have fallen in?
Have had mice in the past but no signs recently. Can't rule that out but as in previous post, looks like the clog is cleared.

Kids? Could someone have let a ball roll under there?
This drain is nowhere near where a person could let anything get in there accidentally.

Has your basement ever flooded? I've have neighbors who had just a little water entering between the floor and the foundation, but it was enough to carry a towel over to the floor drain and plug it up.
Never had flooding. No other signs of foreign objects, especially not rags or towels.

The water should sit a few inches below the level of the floor. Could you tell what you sucked up? Was it just general nastiness or was there anything recognizable in there?
General nastiness. No objects like paper, cloth, wood, etc.

BTW the house is 15 years old, first time this has happened. I'll leave a note for the next owner to check in 2025. ;)

[Joey P]

BTW the house is 15 years old, first time this has happened. I'll leave a note for the next owner to check in 2025. ;)

Make it 2024, A stitch in time and all that.

[BubbaDog]

.................
Why would a drain be underneath the unit in the first place?

Never rule out stupidity.

The chucklehead that designed and built my house put the drain (which clogs with dust and water) right under my furnace unit.

The chucklehead that bought the house (me) missed that little transgression when he inspected the place.

I have to run a snake from my sump pump to the furnace about once a year to keep the drain open for my AC condensation.

I'm replacing my furnace and water heater next month and I'm hoping that I can at least create a little bit of elbow room to get at the drain. If nothing else, I'll be able to give it a good cleaning before the new unit goes in.

[CookingWithGas]

.................
Why would a drain be underneath the unit in the first place?

Never rule out stupidity.

The chucklehead that designed and built my house put the drain (which clogs with dust and water) right under my furnace unit.Isn't that drain one of the first things they do when they build a house? Wouldn't it be more accurate to say that the HVAC guys put put the furnace right on top of the drain?

The design philosophy of my house seems to be to have an upscale design but use the cheapest possible parts and labor to build it.

[Melkor28]

Quote:
Originally Posted by CookingWithGas
.................

Isn't that drain one of the first things they do when they build a house? Wouldn't it be more accurate to say that the HVAC guys put put the furnace right on top of the drain?

The design philosophy of my house seems to be to have an upscale design but use the cheapest possible parts and labor to build it.


With out knowing the dimensions of the furnace room, where to put the A/C unit so the door can open, and the duct can go up through the rafters, and a whole slew of other information; don't blame the HVAC guys. It would be more accurate to blame the General Contractor for lousy coordination. And if it was put in years after the house was built; decisions like.. "Do we move the floor drain to install the HVAC?" are made. Usually with, nope too much $.

Yes, defending the Tinknockers, feel I have to. ;)

[raindog]

Unless you know you have a problem with the floor drain, (That's know, not suspect) don't do this.

There are many reasons for what you're experiencing, but a clogged floor drain is probably the least likely cause.

[raindog]

The most common cause is the condensate drain in your [excellent] pictures is clogged.

The second most common----believe it or not-----is that your unit is low on freon. (and there are some specific things that happen that causes the water on the floor)

I think Joey P is dead on. Don't mess with that ductwork.

If you want give us more info we can step you through those two scenarios. (or if you want to PM me I'll give you my phone number)

raindog
hvac guy

[raindog]

FWIW those duct connections are "S and Drive" connections. The tinner bent up a flange on the longer dimension and bent two 1/2" flanges on the shorter dimensions and "locked them" together with a drive cleat. (the "Drive Slip or Cleat (A)" figure in Joey P's cite)

It would be a pain for someone experienced (and had the right tools) but a real pain for those who aren't.

And anyways.....it's likely not the problem.

[raindog]

For those playing at home, those pictures in Joey P's cite are a little confusing. The "long" dimension in CookingWithGas's photo is actually the "S lock" and it is represented in the Hemmed "S" Slip (C) drawing.

The "short" dimension is represented in the Drive Slip or Cleat (A) drawing.

So.....the ducts are 'joined' or 'fit up' with the S locks, and locked together with a drive [cleat].

Voila! an "S&D" connection. So.....those 2 drawings are always needed for an S/D duct connection.

[ecenur]

I'm going to be replacing my furnace tomorrow, and buying a new furnace filter I am thinking about buy a few extra furnace filters cutting them out and making different filters out from them and use them in different places, haven't tried it before but a lot of people are say it's a good idea and apparently it works really well.

[t-bonham@scc.net]

With out knowing the dimensions of the furnace room, where to put the A/C unit so the door can open, and the duct can go up through the rafters, and a whole slew of other information; don't blame the HVAC guys. It would be more accurate to blame the General Contractor for lousy coordination. And if it was put in years after the house was built; decisions like.. "Do we move the floor drain to install the HVAC?" are made. Usually with, nope too much $.The location of the furnace is often fixed, and sometimes happens to be right over the floor drain. So you're stuck. But the best option in such cases is to raise the furnace up 4"-6" above the floor, using cement blocks or similar -- you can almost always do that without major changes in the ductwork. That leaves some open space underneath so that you can get at the drain without having to do anything to the furnace or ductwork.

[raindog]

I'm going to be replacing my furnace tomorrow, and buying a new furnace filter I am thinking about buy a few extra furnace filters cutting them out and making different filters out from them and use them in different places, haven't tried it before but a lot of people are say it's a good idea and apparently it works really well.

This is generally a bad idea, unfortunately.

[ecenur]

This is generally a bad idea, unfortunately.

Really? A lot of people are actually using a normal home Furnace Filter (http://www.iaqsource.com/furnace_filters.php) to construct cabin filters for their cars, and other types of filters that could be useful. I also though it would be a good idea my self, I didn't not really expect it to work as well but I thought it would be the job to a certain point.

[ZenBeam]

It depends on what you mean. I first took it to mean you were going to use additional filters in your HVAC setup, which is bad becaue it can cause too much resistance to air flow. The furnace ductwork and fan are sized to take into account a filter, but not two or three in series. I suspect that's what raindog is thinking as well, but I don't know.

Rereading, it sounds like you're talking about using them in other, non-HVAC places. Knock yourself out, I guess.

[dzero]

I haven't read every post and it looks like the thread was dormant for a couple months. Anyway, I wanted to mention one possibility that I haven't seen come up. On the left side of the furnace (first photo), it looks like the OP has an AprilAire humidifier. I have what appears to be the same model. When I got the new furnace, we kept the original humidifier and ever since, it has malfunctioned - at least partially. It's supposed to shut off with the furnace blower. It does, but only if the humidity is over what you have set. So if it's set to 35% but it's 30% and the furnace shuts off, the humidifier's intake valve won't close. So you have water running through the humidifier continuously until you hit the desired humidity.

I plan on getting that fixed this year (finally) but I didn't worry about it previously since the a/c coil and humidifier dump into a copper tube that runs to the sump pump. Also I normally keep the humidity low enough that's it's only occasionally a problem.

The OP's setup might be sufficient to dispose of condensate but not capable of handling the larger volume of water you would get with a malfunctioning humidifier.

[raindog]

Really? A lot of people are actually using a normal home Furnace Filter (http://www.iaqsource.com/furnace_filters.php) to construct cabin filters for their cars, and other types of filters that could be useful. I also though it would be a good idea my self, I didn't not really expect it to work as well but I thought it would be the job to a certain point.

ZenBeam captured my sentiments. Furnace blowers are engineered to "overcome" certain expected resistances. Your A/C coil, ductork and filter are some of the common resistances.

Fairly commonly HVAC systems have resistances that are greater than design; ductwork that is too small, too many registers closed off, dirty coils, and dirty or too dense filters are common.

If I understood you, (and maybe I didn't...) you're thinking of putting several 'local" filter in the ducts/registers.

As a fairly good general rule, you're adding too much resistance to the system. One good quality filter at the furnace location is all you really need.

[raindog]

I haven't read every post and it looks like the thread was dormant for a couple months. Anyway, I wanted to mention one possibility that I haven't seen come up. On the left side of the furnace (first photo), it looks like the OP has an AprilAire humidifier. I have what appears to be the same model. When I got the new furnace, we kept the original humidifier and ever since, it has malfunctioned - at least partially. It's supposed to shut off with the furnace blower. It does, but only if the humidity is over what you have set. So if it's set to 35% but it's 30% and the furnace shuts off, the humidifier's intake valve won't close. So you have water running through the humidifier continuously until you hit the desired humidity.

I plan on getting that fixed this year (finally) but I didn't worry about it previously since the a/c coil and humidifier dump into a copper tube that runs to the sump pump. Also I normally keep the humidity low enough that's it's only occasionally a problem.

The OP's setup might be sufficient to dispose of condensate but not capable of handling the larger volume of water you would get with a malfunctioning humidifier.
I don't your level of gumption/skills, but this is a fairly doable fix. PM me if you want to give it a go yourself.