Thread: Condensate drain diagram

Does anyone have a correct diagram or picture of a horizontal (attic) mounted A/C unit with both primary and secondary traps with the vent in the proper location? I would love to have a diagram I could put in my reports to show how it is supposed to be done.
I keep looking for a correct example on my inspections, but NOBODY does it right! I have gotten close a couple of times, but there is always some kind of defect that I do not want to use as an example.
Thanks, Jim

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Jim,

I think Jerry Mc. posted one on here before but I can't locate it at this moment. Maybe he can find it if he did.

Your right, I've never seen the condensate drain lines done correctly either. Seems something is wrong with all of them.

Found one close the other day but it had condensation pouring out of the secondary to the exterior. So no go.

It looked correct looking down at it from the front of the unit, but looking at it from the side it was obvious the primary drain line was running uphill causing the condensate to back up into the coil and drain to the secondary.

Rick

As I recall a great deal of discussion took place over this

This is what both of today's looked like
Yep, that's over an inch of rusty water in that pan. No float or moisture sensor.

Your right Barry, that is part of the reason I was so specific in my request. I wanted to avoid beating that horse to death again

Originally Posted by Jim Luttrall

Does anyone have a correct diagram or picture of a horizontal (attic) mounted A/C unit with both primary and secondary traps with the vent in the proper location? I would love to have a diagram I could put in my reports to show how it is supposed to be done.
I keep looking for a correct example on my inspections, but NOBODY does it right! I have gotten close a couple of times, but there is always some kind of defect that I do not want to use as an example.
Thanks, Jim

I took this picture of an installation manual last week at an inspection. Sorry it only talks about the secondary drain. In my area the AHJ's do not require a secondary if a pan is installed with an automatic cutoff attached in the pan.

Jim
This is all I could find in my files at the moment - hope it helps?

Fritz, we are tripping over terminology I think. I don't want to tread on Jerry P's turf here by correcting anyones terminology, but for the sake of clarity, there are three distinct drain systems in most attic mounted a/c units here. The primary drain, the secondary drain, and the emergency or overflow pan and drain.
Both the primary and secondary drain ports connect to the evaporator drain pan inside the cabinet and will leak conditioned air out the pipe if there is no trap or if the vent is installed on the wrong side of the trap on the primary.
The emergency overflow pan does not need a trap since it is just an external pan and drain to a conspicuous location.

Scott the verbiage above the diagram that says in black and white that both the primary and secondary need to be trapped is very helpful. Any idea what brand of unit or model that was?

Thanks Jerry M. I think I have already stolen most of those from your previous posts, but I will check my files, you never know when you are going to need a good diagram.
I am still looking for that holy grail photo or diagram that shows everything correct though.
Thanks everyone!
Jim

Jim,

That diagram is in all the Lennox installation manuals, for example:

http://www.hvac-direct.com/pdf_files...on/505059c.pdf

Screen captures for anyone who needs them:

Thanks Michael, I have looked at several Lennox and other instruction sheets and never found the clear cut verbiage until today from you and Scott.
BTW, what program do you use for the screen capture?
Jim

Fritz, I will agree with you on that, almost every one I see is wrong even in new builds.
I see bunches of pans that have big rust spots under the secondary pipe due to condensation forming in the pan from the cold air blowing on it.
As I tell my customers, go up in the attic and pass your hand near the a/c unit and connections when it is running. If you feel cold air; it is wrong.

Simple explanation that is easily understood by everyone except the guy running the condensate drains!
I also add to use mineral oil to prime the secondary trap to provide for and prevent evaporation of the trap seal.

For those math whizzes out there, I would like to see an annual dollar cost of energy for those 3/4 inch holes. I also wonder if the duct blaster testing guys seal those holes during the test. It seems an open 3/4 inch hole or two would eat up most of the leakage tolerance for the duct system. I have read some less than flattering practices for the energy rater techs that work for the builder though.
Jim

MW Snap here on the laptop. It's pretty good, but I have a better one on the office computer, can't remember its name offhand, I'll have to look it up.

Meanwhile, can someone point me to the code section which requires that condensate indirect waste drain connections be air gaps rather than air breaks?

Originally Posted by Jim Luttrall

I don't want to tread on Jerry P's turf here by correcting anyones terminology, but for the sake of clarity, there are three distinct drain systems in most attic mounted a/c units here. The primary drain, the secondary drain, and the emergency or overflow pan and drain.

Close.

- The primary drain,
- the secondary drain,
- the auxiliary pan and drain
- a cutoff switch which will shut the unit off and allow overflowing condensate to run all over, damaging whatever it can

Originally Posted by Michael Thomas

Meanwhile, can someone point me to the code section which requires that condensate indirect waste drain connections be air gaps rather than air breaks?

INDIRECTWASTE PIPE. A waste pipe that discharges into

the drainage system through an air gap into a trap, fixture or
receptor.

While nothing "allows" for the condensate to be connected to a sanitary drain, that would be an "indirect waste" and would fall under the requirements for, and definition of, "indirect wastes", see above.

However, the above said, I will repost the code section which does not allow for condensate to be connected to the sanitary waste system through the trap as shown in that drawing:

- P2706.3 Prohibited waste receptors.

Plumbing fixtures that are used for domestic or culinary purposes shall not be used to receive the discharge of indirect waste piping.

- - Exceptions:
- - - 1. A kitchen sink trap is acceptable for use as a receptor
for a dishwasher.
- - - 2. A laundry tray is acceptable for use as a receptor for a
clothes washing machine.

I.e., the only traps/fixtures used for domestic OR culinary purposes which are allowed to receive indirect wastes, and the only wastes those are allowed to receive are: 1) kitchen sink trap may receive waste from a dishwasher; 2) laundry tray/sink may receive waste from the clothes washing machine.

Thanks.

So, in theory at least, most every drain pan on a utility room floor is incorrectly plumbed...?

Oh man... no way I'm gonna' win *that* battle...

Originally Posted by Michael Thomas

So, in theory at least, most very drain pan on a utility room floor is incorrectly plumbed...?

Yep.

Oh man... no way I'm gonna' win *that* battle...

You can, it just takes patience and stick-to-it-tiveness.

Here is the reference for the water heater pan drain:


P2801.5.2 Pan drain termination.

The pan drain shall extend full-size and terminate over a suitably located indirect waste receptor or shall extend to the exterior of the building and terminate not less than 6 inches (152 mm) and not more than 24 inches (610 mm) above the adjacent ground surface.

Correct, "over", not "into" or "in". And that "over" height must meet the air gap space requirements shown in the code, basically twice as high above the drain as the pipe is large, 2" minimum (basically - it's more complicated, as I showed in the other recent post related to this very thing).

I like this one I saw this week . . .

[ATTACH][/ATTACH]

Aaron

OOooh.... that's goinna create a NAsty smell!!

rr

Originally Posted by Richard Rushing

OOooh.... that's goinna create a NAsty smell!!

rr

It's trapped what's the problem?

During the winter months, at least where the heating season is longer, evaporation can occur. There is a chance that sewer smells can enter the house. Over the years I only came across one house where sewer smells were entering the house. When I turned on the furnace, it smelled.

I saw this yesterday..
I'm used to seeing the "float switch" variety installed on the catch pan.
this one won't even allow water to hit the pan...

Victor:

One stop shopping:

Likely, other's make a similar package.

Originally Posted by Jerry Peck

Here is the reference for the water heater pan drain:


P2801.5.2 Pan drain termination.

The pan drain shall extend full-size and terminate over a suitably located indirect waste receptor or shall extend to the exterior of the building and terminate not less than 6 inches (152 mm) and not more than 24 inches (610 mm) above the adjacent ground surface.

Correct, "over", not "into" or "in". And that "over" height must meet the air gap space requirements shown in the code, basically twice as high above the drain as the pipe is large, 2" minimum (basically - it's more complicated, as I showed in the other recent post related to this very thing).

Is there similar language ("over a") for A/C condensate drains?

M1411.3 in the 2003 IRC
Too long for me to type today, but there is a substantial amount of info there.

Originally Posted by Michael Thomas

Is there similar language ("over a") for A/C condensate drains?

This is a specific as it gets ( which is 'not very' specific) for a/c condensate drains (the main thing it says is 'where not to' discharge to):

From the 2006 IRC. (underlining is mine)

- M1411.3 Condensate disposal.

Condensate from all cooling coils or evaporators shall be conveyed from the drain pan outlet to an approved place of disposal. Condensate shall not discharge into a street, alley or other areas where it would cause a nuisance.