Thread: AC condensate drain arrangement

I questioned the condensate arrangement of this coil. It is above a garage and the safety pan and condensate line drain into the same drain. Also the primary drain line is slope incorrectly and the water is draining into the pan not the drain. I thought a secondary drain line was required to terminate at a different location. What are the requirements with this set up? Plus the humidifier is missing a drain pan.

Thanks

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Matthew,

What's that big thing on the end, a humidifier?

Your photo shows only a primary condensate drain, no secondary condensate drain (you can see the blue plug in the secondary opening next to the primary condensate drain line).

Both the primary and secondary condensate lines require traps. There is no trap on the primary condensate line, and, there is no secondary condensate line at all.

The secondary condensate line should be from that blue plug opening to a trap to the auxiliary drain pan. The auxiliary drain pan drain line does not need a trap (and none is installed, that's good).

Now, back to that big thing on the end ... what is it and, no, it should not be tied in with the primary condensate drain line. As connected now, when the primary condensate drain line backs up, that 'big thing on the end' will also back up.

The pan drain line should drain to the exterior thru a soffit preferably above a window. This should be set up like that so the home owner can recognise when the primary drain is clogged or the system has other concerns like possible inner pan rot and needs to be serviced.

Boy am I about to get it.

And yes you need a secondary drain line to the pan

Ted,

When was the last time you saw a secondary line with a trap? I can't recall seeing one either.

All the secondary drain lines I see elbow directly into the drain pan which then has a drain from the pan to the exterior.

rick

Originally Posted by Ted Menelly

The pan drain line should drain to the exterior thru a soffit preferably above a window.

Or ...

The auxiliary pan drain line could go no where and there could be a cut off switch in the pan instead.

I personally like to see both the auxiliary drain pan drain line *and* the cut off switch.

Ted, who you trying to kid about homeowners recognizing that water dripping in front of the window as meaning the a/c needs servicing?

That's the reason for the cut off switch also - when that drain line clogs up, the cut off switch shuts the unit off (if the switch works - which is why I also like having the drain for the pan, each one acts as a failsafe for the other).

I know, how silly of me. But, I do tell everyone of my clients where the exterior drain is (always over a window) and what it means if water is dripping out of it. As far as the cut off switch, the line better still drain to the exterior over a window in case the son of a gun does not work......

Just me

Im trying to visualize the first photo. It looks like the primary drain line slopes up, at least where it ties into the "common drain". Where does the line go that runs off the tee? No vents? It looks like something got really hot on the cabinet (notice the black spot). Did they use a torch to cut it, or was something else going on?

Jerrys right the belt and suspenders approach (cut off switch and drain pan line) are the way to go.

I also mention the washer drain pan outlet & the water heater relief valve outlet along with the A/C backup drain pan outlet in my reports. I tell them that if they see water coming from these pipes they get to get the culprit serviced.

Jerry,
Yes it is a humidifier, and it is missing a drain pan under it. And as you know, there have been one or two humidifiers that have leaked in the past. Here is one more photo. And the primary drain line is sloped in the wrong direction, causing water to drain into the pan. You can see the water in the one photo.

Improperly sloped or sagging condensate lines can be another thing to watch for. Just had a contractor friend tell me that he did a renovation and added central AC in attic. Long condensate line with elbow. Owner called him last week says ceiling and walls wet. He rushed over and due to sag in condensate line water stayed in line and froze during the winter and elbow broke apart. This job never ends!

Originally Posted by mathew stouffer

Jerry,
Yes it is a humidifier, and it is missing a drain pan under it. And as you know, there have been one or two humidifiers that have leaked in the past...

I'm not sure he does know. There isn't much call for humidifiers in Florida after all. Jerry - were you joking when you asked if the big thing on the end was a humidifier?

Originally Posted by mathew stouffer

And the primary drain line is sloped in the wrong direction, causing water to drain into the pan. You can see the water in the one photo.

Originally Posted by mathew stouffer

Also the primary drain line is slope incorrectly and the water is draining into the pan not the drain.

Yeah, I didn't mention the reverse slope because you had already done so.

Originally Posted by mathew stouffer

I questioned the condensate arrangement of this coil. It is above a garage and the safety pan and condensate line drain into the same drain.

I thought a secondary drain line was required to terminate at a different location. What are the requirements with this set up?

You are intermixing two terms: secondary drain line and safety pan drain line.

That does not have a "secondary condensate drain line", from my first response:

"Your photo shows only a primary condensate drain, no secondary condensate drain (you can see the blue plug in the secondary opening next to the primary condensate drain line)."

"Both the primary and secondary condensate lines require traps. There is no trap on the primary condensate line, and, there is no secondary condensate line at all."

"The secondary condensate line should be from that blue plug opening to a trap to the auxiliary drain pan. The auxiliary drain pan drain line does not need a trap (and none is installed, that's good)."

Now, back to what I think you are asking: The auxiliary pan (safety pan) does not require a drain line, it could have a cut-off switch. However, if it does have a drain line, that drain line is not supposed to be connected to the primary drain line, it is to be routed at Ted said - to someplace conspicuous where the homeowner will see it, typically the drain pipe is sticking through the soffit above a window.

That said, I don't think both are connection to the same drain line in that photo, if they are, you have a bigger problem.

It think both are going into the same chase, with two drain lines running down through that chase. One of those drain lines should be for the primary condensate drain line and the other should be for the humidifier drain line. Both should be properly trapped.

Then, the secondary drain from the a/c should drain into the auxiliary drain pan under the AHU, and the secondary drain line should be properly trapped. That auxiliary pan *does not require* a drain, however, if it has a drain line, it should be routed as stated above. It could have a drain line *or* a cut-off switch, I prefer both.

Finally, the humidifier should (I think, I really don't know much about humidifiers as all we ever do is dehumidify) have an auxiliary pan under it. I suspect that auxiliary pan could either be drained of have a cut-off switch too????

Now back to my "That said, I don't think both are connection to the same drain line in that photo, if they are, you have a bigger problem." ...

*IF* those *are* both draining into a single drain line, then the top of that drain line is *at the attic floor*. When that sucker backs up ... you get the picture ... *water is going to go everywhere*.

That's why I think that is just a chase for the two separate drain lines.

Originally Posted by John Arnold

I'm not sure he does know. There isn't much call for humidifiers in Florida after all.

John,

Correct (see my post above) - I am not sure that humidifiers require an auxiliary pan under them, makes sense, but is it required?

Correct again -(also in my post above) - why on earth would one want to humidify humid air?

Jerry - were you joking when you asked if the big thing on the end was a humidifier?

Correct again!

Originally Posted by David Banks

Improperly sloped or sagging condensate lines can be another thing to watch for. Just had a contractor friend tell me that he did a renovation and added central AC in attic. Long condensate line with elbow. Owner called him last week says ceiling and walls wet. He rushed over and due to sag in condensate line water stayed in line and froze during the winter and elbow broke apart. This job never ends!

David,

Wouldn't a water filled trap pose the same problem?

Not being in freezing country, I've never thought about that. That could be a problem for every AHU in an attic, couldn't it?

Originally Posted by Jerry Peck

David,

Wouldn't a water filled trap pose the same problem?

Not being in freezing country, I've never thought about that. That could be a problem for every AHU in an attic, couldn't it?

Maybe? Did not get details. Maybe the elbow came apart due to poor installation. Maybe defect in elbow? I thought he said it shattered at the elbow. I will try to get more info.

That same thing just happened here in a house I inspected this week. They have an air handler and humidifier in the attic, and something froze in the winter time and caused a big problem. I told my client I would remove the humidifier or disconnect it if it were up to me. I don't know what he'll end up doing with it.

I could see the traps freezing, but there should be enough room for expansion so that the pipes don't crack, or at least I hope so.

Here are the condensate drain(s) from today's crawlspace. HVAC was dated 5/2004. House built in 1988

- Primary and secondary share the same pipe.
- Elbow is broken and dumps all the condensate directly into the crawlspace.
- Condensate pipe would run uphill if it wasn't broken
- Resulting puddles create a weather cycle effect so that the crawlspace evaporates enough water for it to condense on the duct work and rain on to the vapor barrier to start the cycle again
- Disconnect panel was beginning to rust a tad
- Some of the ducts were shedding their skin

HVAC was dated 5/2004

Originally Posted by Bruce Ramsey

- Some of the ducts were shedding their skin

Owlflex.

That's why in some of your photos is shows new flexible duct, those have already been replaced - improperly I will add.

Might as well go ahead and recommend that all remaining Owlflex duct be replaced now, it will need it sooner or later, as evidenced by that which was already replaced "sooner", so now is "later".

Yeah, there were a number of issues with the ducts. I was trying to not clutter up the condensate drain thread with duct pictures but you dragged them out of me.

The house also had Polybutylene plumbing, powder post bettles and "old house bore bettles" (according to pest control guy).

3 season porch with no permits. City made the current owners strip down the porch to allow for inspection and new permits. Otherwise the house was 20 odd years old and had minor 20 year old problems.

Those pictures were enough to make me glad that crawl space units are a rarity here (along with crawl spaces.)

Or basements

Condensate drain piping for cooling coils changes every other week in this part of the world. First the condensate drain had to be trapped and the secondary drain port was either used to vent the primary with a section of open piping turned up or was just left open. Then it changed to the secondary drain has to be capped off (this did not work). Then no trap in the condensate drain line and the drain line had to be connected to an “active trap” (i.e. bathroom sink drain ahead of the plumbing trap for the sink). The drain line for the lower catch pan has always been required to be routed to the exterior of the house and generally under the roof overhang.

When inspecting the condensate drain I just determine if the primary drain will work, that the secondary drain port, if open, will flow to the lower catch pan and the lower catch pan has a drain line that is at least ¾” in diameter that is routed to the exterior. The primary and the secondary drain ports should not be connected together.

Because the cooling coils in this area produce up to 6 gallons of water an hour, the main condensate drain line must be 1 ¼” in diameter. You are only allowed to used three feet of ¾” diameter piping from the cooling coil drain ports to the primary condensate drain location. Also rubber connectors are required at the ¾’ diameter drain piping connection to the 1 ¼” diameter main condensate drain line connection so the drain lines can be serviced.

Don Merritt
Germantown, Tennessee

Aren't the first four feet of the primary supposed to be insulated to stop condensation from forming?

Originally Posted by Edward Loughran

Aren't the first four feet of the primary supposed to be insulated to stop condensation from forming?

When run through an attic or in or above living space, the entire primary condensate line is supposed to be insulated, for that purpose.

N1103.3 Mechanical system piping insulation.

Mechanical
system piping capable of carrying fluids above 105°F (40°C) or
below 55°F (13°C) shall be insulated to a minimum of R-2.

Jerry they don't enforce that here. I have never seen a insulated condensate drain pipe.

In scanning the thread, maybe my bad, I did not notice anyone mentioned that the unit is not supported a minimum of 4" above the auxilary drain pan. Normaly the installer will use the same 4 X 8 X 16 blocks that are used in crawlspaces. This I believe is a code requirement. This is also the reason there was not room for a trap or correct pitch of the drain line.

There is no cross connection possible at the airhandler or the furnace. The original reason for a trap was the advent of the heatpump, where negitive pressure created an air-dam at the drain. We never used traps prior to the heatpump. A trap at the secondary is a waste of good PVC, it is dry unless there is a problem, and no body is going to prime it! Oil is an option but I have never seen anyone do it.

I believe the only reason the mfg. requires traps on all units is that the installer could not figure out where they are required, so mfg. fixed the problem with requiring all units. If you think the installer knows about condensate lines, traps, clean-outs and vents, I have hundreds of pic's of trap clean-outs without caps to dispel that illusion.

Originally Posted by Jerry Peck

When run through an attic or in or above living space, the entire primary condensate line is supposed to be insulated, for that purpose.

Uh, no as in no.