I’m starting to see more instances where the primary drain lines from two air conditioners are combined together downstream instead of separately terminated to sink P traps…anybody else? I’m not able to find any specific language against this, as long as the drain line size can handle the tonnage. Thoughts?
we need a picture, your words do not describe what you are seeing
Separately or not… it’s not allowed in my area at all. Does Texas allow it in your area? What does your AHJ say??
Joe, I have yet to see 2 primary condensate drains connect to 1 before entering the waste line. Always separate. (I do often see the secondary drain lines connect before exiting the home)
Interested to see what you find about this in case I end up encountering the same situation.
I see this frequently here. Based on the Codes this is the paragraph allowing it.
M1411.3.2 Drain pipe materials and sizes. Components
of the condensate disposal system shall be ABS, cast iron,
copper, cross-linked polyethylene, CPVC, galvanized
steel, PE-RT, polyethylene, polypropylene or PVC pipe or
tubing. Components shall be selected for the pressure and
temperature rating of the installation. Joints and connec-
tions shall be made in accordance with the applicable pro-
visions of Chapter 30. Condensate waste and drain line
size shall be not less than 3 / 4 -inch (19 mm) nominal diame-
ter from the drain pan connection to the place of conden-
sate disposal. Where the drain pipes from more than one
unit are manifolded together for condensate drainage, the
pipe or tubing shall be sized in accordance with an
A 3/4", Sched 40, PVC line can gravity drain approximately 11 Gallons Per Minute as long as no obstructions are present and proper slope is provided (1% horizontal slope is required per codes). The amount of condensate an evap coil can create depends on various factors but can generate upwards of 20 Gallons Per Day. As can be seen combining primary or secondary condensate disposal lines should not be an issue as long as the path is maintained.
So far in my area I have yet to see an AHJ amend this requirement for separate discharge lines for each unit.
Yes Brandon, that is the primary drain line termination I am referring to. Further upstream the condensate drain lines are merged before they terminate to this point. It appears per the Plumbing Code chart below that condensate drain lines are allowed to be combined as long as the tonnage capacity does not exceed a certain threshold…at which point a larger drain line would be required. Since this drain line was 3/4" it can handle condensate up to (20) tons of a/c.’
314.2.2 Drain pipe materials and sizes.
[M] TABLE 314.2.2 CONDENSATE DRAIN SIZING
|EQUIPMENT CAPACITY||MINIMUM CONDENSATE PIPE DIAMETER|
|Up to 20 tons of refrigeration||3/4 inch|
|Over 20 tons to 40 tons of refrigeration||1 inch|
|Over 40 tons to 90 tons of refrigeration||1 1/4 inch|
|Over 90 tons to 125 tons of refrigeration||1 1/2 inch|
Thanks for your opinions fellas.
Yep, thanks Emmanuel.
That’s all good and well regarding the (multiple) condensate line sizing, but the AHJ issue I see is the INCREASED SIZING FOR THE SINK TAILPIECE/P-TRAP/DRAIN PIPE!! Technically, that also needs to be increased in size as an extension of the condensate drain line… and that just isn’t gonna happen!