Thread: AC condensate seconday drains

I came across this HVAC split system, and noticed that there did not appear to be a secondary condensate drain in place. Aren't both primary and secondary drains required?

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Originally Posted by Ron Bishop

I came across this HVAC split system, and noticed that there did not appear to be a secondary condensate drain in place.

Nope, sure taint one there.

Aren't both primary and secondary drains required?

Yep. That's why the manufacturer installed that secondary drain opening.

Also needs a pan under the unit, unless the return is up through the bottom, in which case ... things will be a getting wet at times.

Is that an orange extension cord in the attic being used for ... ?

Insulation missing from that wall too.

Yes required.

No, not one there. Hope you wrote that up as a defect.

have had the pan arguement several times, I have found this wording or similiar in most installation instructions for split systems, so if not code in your area, this helps...

The manufacturers recommend the following: “In compliance with recognized codes, it is recommended that an auxiliary drain pan be installed under all evaporator coils or units containing evaporator coils that are located in any area of a structure
where damage to the building contents may occur as a result of an overflow of the coil drain pan or a stoppage in the primary condensate drain piping”.

Where is it documented that a secondary condensate line is "required"? I understand a manufacturer can illustrate a connection or recommend a connection. However, unless there is a building code in effect at the time of permit application for the installation or the manufacturer states that failure to follow their recommendations will void any warranty coverage, I do not understand why it would be classified as a defect, deficiency, or anything other than an advisory issue.

Just to be clear, I know why one should be installed. I have a note that covers the issue in reports. I just have never seen a secondary condensate line installed anywhere.

I don't know what code is in effect in your area, but this is covered in M1411.3.1 in the 2003 IRC.
... a secondary drain or auxillary drain pan shall be required...

Originally Posted by Stuart Brooks

Where is it documented that a secondary condensate line is "required"? I understand a manufacturer can illustrate a connection or recommend a connection. However, unless there is a building code in effect at the time of permit application for the installation or the manufacturer states that failure to follow their recommendations will void any warranty coverage, I do not understand why it would be classified as a defect, deficiency, or anything other than an advisory issue.

Because it is more than advisory by the manufacturer ...

... it is REQUIRED by the manufacturer.

Attached is from Carrier installation instructions.

This is from an article by Ray Moore,
principal with Professional
Engineering Services in Salt Lake City, ASPE vice
president, legislative, and chair of the Utah Building

Codes Commission Plumbing Advisory Committee.

The

IPC has some additional requirements for condensate drain

pans that are not included in the UPC. Section 314 of the IPC is
taken directly from the International Mechanical Code. Section
314 of the IPC requires that additional protection be provided in
case the drain line gets plugged, and the condensed water over-

fl

ows the drain pan and damages building components.

The

IPC also requires that an auxiliary or secondary drain

system be provided. Th

ere are four different methods for compliance.

The fi

rst method is to provide a secondary drain connection

on the primary drain pan. Th

is secondary drain must

drain to a place where occupants would notice if a stoppage
existed in the main drainage system. The

second method is to

provide a condensate drainpipe from an auxiliary or secondary
drain pan. Th

e third and four methods listed in the IPC require a

water level detector and shuts of the air-conditioning equipment
to be provided so additional condensed water is not produced.
Typically, this water level detector is a sensor or fl

oat switch.

As plumbing engineers, we need to work with the mechanical
engineers in the design of the heating and air-conditioning
systems to provide condensate drains from the air-conditioning

equipment.

I did not save the link to the article but I think you can get there with
PSDMAGAZINE.ORG

With the duct beneath the unit, as pictured, using a float switch at the secondary condensate port would be my preferred fix. Here is a pic of float switch at recent inspection. "Unit was in utility room, on slab, no pan"

Quote didn't look like that on pre-view??? Don't know where all the extra returns came from but you can read it!

Originally Posted by Vern Heiler

With the duct beneath the unit, as pictured, using a float switch at the secondary condensate port would be my preferred fix. Here is a pic of float switch at recent inspection. "Unit was in utility room, on slab, no pan"

My preferred alternative is what used to be required in Florida, that an auxiliary drain pan was required under the unit, and when an auxiliary drain pan cannot be installed under the unit, then the auxiliary drain pan be placed beside the unit with the secondary condensate drain line running to it. Then, that auxiliary drain pan has two options (I prefer both for redundancy): 1) route the drain line from the auxiliary drain pan so it drains to a conspicuous location; 2) a shut off switch can be installed to shut the unit down.

The reason I do not like just the shut off switch in the secondary condensate drain outlet port is, sure, it shuts the unit off, but if the coil is iced up (and we've all seen iced up coils) what happens when the unit shuts down and that ice melts into water - where does that water go? Answer: That was overflow and goes all over, damaging what you were trying not to damage. Placing the auxiliary drain pan next to the unit and piping the secondary condensate to that auxiliary drain pan gives a place where that water can go without overflowing or damaging anything.

I see alot installed with the secondary line draining in the pan. The pan then has just the float switch which I test. I've written up the lack of a drain line from the pan but got hassled from the installer on whether it is required. It appears the swtch is sufficient, but on a frozen coil with a stopped up primary drain this could lead to damage. My question is: Is a p trap required on the primary and secondary drain lines. I see alot of installs that appear to terminate at a vent with no p trap. I write them up any way because of the possibility of sewer gasses entering the controlled space. Is there code for this?

Originally Posted by SAL IACONO

My question is: Is a p trap required on the primary and secondary drain lines. I see alot of installs that appear to terminate at a vent with no p trap. I write them up any way because of the possibility of sewer gasses entering the controlled space. Is there code for this?

Required by the manufacturer's installation instructions.

Code references manufacturer's installation instructions so they become "code by reference".