HVAC Primary Drains

[robert1966]

What do you think about primary HVAC lines on homes that drain into one or more of the sinks. I know this is allowed in our area and is quite common, even in my home.

But these lines and the P-trap at these sinks seem to clog a lot more frequent than when the HVAC lines drain to the exterior. I have spoke with several master plumbers and they all seem to agree that this is a bad system.

Input is appreciated

[Marc]

The biggest problem that I have seen with HVAC drains is that the 1 1/2" or 2" drain that is provided by the plumber is too far away from the evaporator coil. The AC contractor responds by installing a much longer 3/4" condensate drain line to reach it. That 3/4" is going to plug up more easily and more often than the plumber's pipe. It's seldom a problem when kept short, but lengthen it and it's a constant headache especially with long level runs.

Marc

[Erby]

What, AC guys don't understand that crap runs downhill, not level?

And they keep installing those "pre-formed running traps" that manufacturer's instructions say "DON'T USE"l.

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