Condensate Drainage

Heat pump air handler located attic with drip pan. Condensate and pan drain pipes connect to a copper plumbing vent. Quality HVAC work!

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wow you don’t see cooper vent much now days was it a commercial Building

“The secondary condensate port was not plumbed to the attic drain pan. As a result, when the primary drain line becomes clogged, the condensate inside the air handler has no path to escape. It will rise in the air handler cabinet until it finds a seam in which to seep out, and may cause rust inside the cabinet. In the worst case scenario, the water may rise until it travels down a duct and will cause ceiling damage when it escapes out a duct seam. We recommend that the secondary port be plumbed to the bottom of the drain pan. Immediate service is not critical and can wait until the next scheduled maintenance.”

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Correct, but the drip pan drain should terminate at a conspicuous location. I also called out the vent pipe connection as non standard.

I struggle with that when there is a float switch present. With a float switch, a pan drain isn’t even required. But if it’s there, it should be installed correctly I suppose. (One solution in your case is to remove the pan drain altogether, which I wouldn’t want to do.)

So what if there is only one visible drain line, attic installation, and it is at exterior of home?

If that’s the primary, I would certainly call that out as unorthodox. While there is no specific rule against it, it will cause discoloration to the roof and is just generally unsightly.

So in this setup you wouldn’t recommend a secondary?

Where damage may occur, you always need a pan with either a float switch, an auxiliary pan drain, or both.

Around here its common practice for drain line to run into the sewer lines. With a larger trap on the condesate line, it should not pose an issue unless you have a back up (then there is poo in the coil). But with both lines running into the vent, both drains should have traps on them.

Many times I see just one line, and a float switch.

What happens if the trap is dry during the heating season? Float switches can fail, just had one last week that was not functional.

Being common does not necessarily equal being acceptable. Any direct discharge like that into a plumbing vent is never acceptable.

Putting a trap on a pan drain is absurd. The pan drain is there for emergencies. And think about it…what would the pan drain trap do? The pan itself is open into the attic!

Be careful about making up your own rules and giving people your own solutions. The next inspector in the house, one who understands the codes, will laugh when he hears the homeowner say, “My inspector said all it needed was a larger trap.”

2006 IRC:

"M1411.3.1 Auxiliary and secondary drain systems. In
addition to the requirements of Section M1411.3, a secondary
drain or auxiliary drain pan shall be required for each
cooling or evaporator coil where damage to any building
components will occur as a result of overflow from the
equipment drain pan or stoppage in the condensate drain
piping. Such piping shall maintain a minimum horizontal
slope in the direction of discharge of not less than 1/8 unit
vertical in 12 units horizontal (1-percent slope). Drain piping
shall be a minimum of 3/4-inch (19 mm) nominal pipe
size. One of the following methods shall be used:

  1. An auxiliary drain pan with a separate drain shall be
    installed under the coils on which condensation will
    occur. The auxiliary pan drain shall discharge to a
    conspicuous point of disposal to alert occupants in the
    event of a stoppage of the primary drain. The pan shall
    have a minimum depth of 1.5 inches (38 mm), shall
    not be less than 3 inches (76 mm) larger than the unit
    or the coil dimensions in width and length and shall be
    constructed of corrosion-resistant material. Metallic
    pans shall have a minimum thickness of not less than
    0.0276-inch (0.7 mm) galvanized sheet metal. Nonmetallic
    pans shall have a minimum thickness of not
    less than 0.0625 inch (1.6 mm).

  2. A separate overflow drain line shall be connected to
    the drain pan provided with the equipment. This overflow
    drain shall discharge to a conspicuous point of
    disposal to alert occupants in the event of a stoppage
    of the primary drain. The overflow drain line shall
    connect to the drain pan at a higher level than the primary
    drain connection.

  3. An auxiliary drain pan without a separate drain line
    shall be installed under the coils on which condensate
    will occur. This pan shall be equipped with a water
    level detection device conforming to UL 508 that will
    shut off the equipment served prior to overflow of the
    pan. The auxiliary drain pan shall be constructed in
    accordance with Item 1 of this section.

  4. A water level detection device conforming to UL 508
    shall be provided that will shut off the equipment
    served in the event that the primary drain is blocked.
    The device shall be installed in the primary drain line,
    the overflow drain line or the equipment-supplied
    drain pan, located at a point higher than the primary
    drain line connection and below the overflow rim of
    such pan."

Joe never acceptable is pretty strong words AHJ around here allows connection to a sewer vent in the attic if the trap is considered as a wet trap and the only time a condensate drain trap can be considered as wet is if the furnace is a 90% efficient and produces condensate in the heat mode

As shown, the connection to the Vent pipe is not allowed. That is not an approved way to connect to a Vent Pipe.

The alarm is cool.

I always tell my clients to have the secondary drain hose penetrating an area near the main entry door. This configuration will allow the secondary drainage piping to be monitored on a daily basis. Attic air handler installations should have the secondary drain piping installed out to the soffit area and right over the main entry door. This would drop secondary condensate right in front of the homeowner, alarming them.

I stand by my remarks. Your AHJ is stupid.

Hey, I personally would not do it, but its allowed here. Matter of fact, My house is done exactly this way. If the trap goes dry in the winter, I guess I will know when i pass the big one in the evening.

Are you quoting code Joe??? BTW I personally think your off the wall comments far outweigh the few I have posted if you want to take stabs at people.

I do realize one can not fix stupid but are you telling me you cannot discharge condensate into a 100% wet trap located in the attic;-):wink:

Charley, if I recall, you do know of a few things about HVAC right? :mrgreen::wink:

It may indeed be “Common” in some areas, that does not make it correct. The way the drain in the picture is connected to the vent piping is WRONG, there are no two ways about it.