In short, should the condensation drain pipe from the waterfurnace series 7 be sealed all the way to where it dumps (the sump pump hole - whatever it's called)?

More specifically, my contractor attached a little pvc to the waterfurnace unit, and that pvc then drops the water into the pvc pipe coming out of my foundation. However, those two pvc sections are not sealed to each other; one just dumps into the other. (The pipe coming out of the foundation runs to the sump pump hole.)

I had pooling in my basement the other day, which probably came from the ac condensation (possibly a partial clog in the pipe that runs under the foundation to the sump pump hole) although I'm still trying to confirm. If I seal the condensation drain all the way (i.e., I seal the pvc from the waterfurnace to the pvc coming out of the foundation), will the waterfurnace unit shut off if the pipe is clogged and the condensation can't drain? (That's what I'm hoping for, so I don't get any more pools, even if the drain pipe clogs or something.)

Thanks a lot.

Yes, there is a safety alarm (basically a bare wire on the upper 1/3 of the condensate pan) which will trigger an alarm when water touches it. It will signal E7 on the thermostat and takes a manual / hard reset, which can be done from the t-stat but typically means their an issue that needs to be address.

A condensate line should be vented after the internal trap if more then 6' horizontal run. Sealing your current "vented" pipe would invite siphoning in some circumstances. Also, your sump could back up into the drain pan if the vent is sealed. The HP will lock out while the sump water will continue to overflow into the unit. I suggest it be drained to an appropriate outfall that can handle the flow without clogging and only if necessary with the help of a condensate pump.

I do like the clear rubber line that is trapped inside the unit, but on our check out list we always double check the plastic retaining clip on the bottom of the pan for "snugness" as they are known to move. I am anal with fit and finish and was having trouble with exact placement of my pvc piping external to the WF units with the hardware they provide. What we end up doing is making the trap a few inches shorted inside the unit and glue a street 90 and a small piece of 3/4" PVC onto the barb x pvc fitting to get us outside the unit. This provides much more support within the unit and keeps everything exactly straight and offers more support.

Is it just pooling around the floor drain? If so you can take the cover off that drain and elbow your condensate drain line down into it.

ACES-Energy, G.O. Joe, and joe.ami. Thank you all for your replies. These are very helpful. (I apologize I'm so late to reply myself. Somehow I wasn't subscribed to this topic. I thought no one had replied.)

It turns out that the water was actually coming from a leak between the ground-loop pipes and the foundation. (See another recent post of mine.)

However, I want to take care of this nonetheless. I had a condensate drain clog at my last house and the result was water everywhere in the basement. It also seems ideal to seal the drain (back to a trap) for radon remediation. (Right now the radon could just come right out the condensate drain although it may be a minimal amount. I'll do a test.)

G.O.Joe your point about the sump backup is interesting and something I had not thought about. Could a backup cause significant damage to the heat pump? The heat pump drain is a few inches higher than the top of the sump pit, so I wouldn't expect backup or siphoning all the way to the heat pump. The sump pit is sealed shut, but there are other drains that are lower than the condensate drain where I would expect backup first. (E.g., the pan for the hot-water heater has a drain pipe that runs to the sump pit that is significantly lower than the top of the condensate drain. I would expect backup there first.)

I could seal the hp drain pipe all the way to the drain pipe that runs under my foundation, but still vent it, i.e., have an open vent pipe sticking up in the air a little bit, between the heat pump drain and a trap that leads to the drain pipes that runs through the floor. Would that be reasonable, or is this a bad idea? (Is it clear what I'm talking about? I could draw a picture if not.)