Condensate drain lines connected together?

[Gene South]

Today I inspected a house with two attic AC units. Each had it's own secondary pan drain lines, however the main drain line of the two units was plumbed togethe for one common drain line. Where does it say in the codes that this is not allowed? Can someone elborate on how the codes read on both primary and secondary drain lines? The photo shows where they are tied. Also, the photos show there are no traps and the TXV is not insulated but that is a different story. Can someone help me on the codes for single drain lines not being connected? Also, as long as we are on the subject, where does it say twin water heater pans cannot be connected together through a common drain?

[Gene South]

Here's the photo showing were the two secondary pans connect together.

[Jerry Peck]

Two condensate drain lines may be connected together, however, the condensate drain line size likely needs to be larger to accommodate the increased condensate.

The primary is required to be trapped coming out of the unit, and trapped before the vent.

The secondary is also required to be trapped and it should not be to the same drain line as the auxiliary drain is.

The auxiliary drain line does not need to be trapped.

[Gene South]

Hi Jerry, Thanks. help me with the photo and terminology...just want to make sure I understand what you mean:

The primary (What I call primary) is the line with the anti-siphon vent . This line goes out and connects to the primary drain line on the on the other unit.

The auxillary (What I call auxillary) is directly adjacent to the primary and is tied to the same drain line as the pan drain (Which I call the secondary...meaning I call the pan drain line the secondary)

Do I have this right?

[Jerry Peck]

See photo.

[Gene South]

Hi Jerry, thanks. Appreciate it.

Gene