Furnace/Central Air drain connection to sewer

[Daniel Parker]

Six years ago we had a new high efficiency furnace and air conditioning system installed. The installer said the drain from the unit had to be connected to the sewer system.

At times we would get water seeping from under the base of the furnace. When we would have our annual inspection the installer would force air through the drain hose…said it must be clogged.

I’ve been under our house several times since the installation but never really paid any attention to the furnace drain connection. The other day I went under just to take a look at it. The drain hose (clear plastic) is installed at the bottom of the trap. Evidently they drilled a hole in the side of the trap, stuck in the hose, and then sealed it with a lot of silicone or something…it’s clear what ever it is.

Is this a proper installation? I wouldn’t think that the amount of water put out by the furnace and central air would build up enough pressure to push against all the water in the trap in order to pass. The line it is connected to is a 2 inch plastic line.

Could this be why the water from that line is backing up into the furnace?

[Retired plbg1Participant]

That is an ilegal connection and should be reported to Plbg. dept. Your drain from AC should be indirect drain, either dropping into a floor drain are a hub drain with a trap on it. If the water would have drained out of the trap you would get a house full of sewer gas, take it loose now and replace the trap and provide a drain for the AC line.

[Retired plbg1Participant]

You should send that co. a letter and tell them about what the installer told you about that drain, see thats why we have Plbg. codes, the guys come and do work and will do it anyway to make it work, anytime there is a connection made to Plbg. pipes there should be a Permit taken out by a LIC. Plumber Cont.

[nicktheplumberParticipant]

As RP said, that trap connection is quite improper and needs to be fixed. Not only doesn’t it drain the AC condensate, but it violates the integrity of the trap and presents a health hazard.

This is a typical example of the half-assed “caulk and pray” installations that we’ve all seen on some sites. Usually done by a DIYer, but, as in this case, by a shoddy non-plumbing trademan whose work somehow impinges on plumbing. HVAC tradesfolk should know better, but some apparently don’t.

NtP

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