Replies

1. 
   MikeHennessy | Sep 26, 2008 03:14pm | #1

   Not that right there is a design nightmare.

   I don't think there is any good way to fix that line. By "unfinished" do you mean "unconditioned"? If so, you're just gonna have to find a way to drain through heated space or, at the very minimum, get it away from the soffit and soffit vents. What's the drop in the line over that 50'? If it's too close to level, that may mean you're getting pooling in the line, which almost guarantees freezing. It may help to increase the drop to speed things along, but I doubt that you'll be able to do that in attic space over a 50' run.

   BTW, if the unit is located in unconditioned space, and you need to provide heat for the drain, that kinda negates the "high efficiency" aspect of the unit, no? The best fix may be to insulate the space where the unit is located, and condition it.

   Mike Hennessy
   Pittsburgh, PA

2. 
   Clewless1 | Sep 26, 2008 05:09pm | #2

   Common misconception about insulating water lines in unconditioned spaces ... yes they will still freeze ... it may take a little longer. Insulation doesn't magically create energy to keep the lines from freezing. That is ... cold temps will eventually get to the water, period (absent a source of heat).

   Possibly heat tape it and put it on a thermostat? I'm assuming you don't have a water trap near the air handler (some systems are installed with it)? You must be trapping water as the condensate drain is only draining in the summer when you are cooling and wringing the water out of the air going across the coil (e.g. using a heat pump?). I'm thinking in the winter, there [should be] no condensate, therefore you must have some trapped water. Do you check your drain pan annually? They can get debris in them that will block the outlet. Maybe someone can clarify my thought here in case I'm missing something (other than the loose screw).

   Or are you talking about a CPVC flue drain for combustion condensation? That will be a different story. I was assuming you were talking about the cooling condensate drain. What do we have here?

1. 
   trident | Sep 27, 2008 03:10pm | #3

   my understanding is these "high efficiency" units produce condensate when they heat as well as when they cool.  hence the reason they really aren't recommended in unfinished spaces.  this partcular setup drains condensate constantly to the sump in the basement about 345 days a year.  It's just those other 20 days a year where up here in Boston the temps drop significantly below freezing.  The heat tape on a thermostat seems to be my only solution but most tapes say right on them..."for supply lines only"  they are not recommended for drain lines.  Any idea why?

1. 
   MikeHennessy | Sep 29, 2008 03:18pm | #4

   Because there usually isn't water in a drain line to conduct the heat away from the tape, so it heats up too much. If you're drain line is plastic, melting is possible.

   Mike HennessyPittsburgh, PA

2. 
   Clewless1 | Sep 30, 2008 04:12pm | #5

   If you are speaking of a heat pump arrangement/system, I don't think it CAN produce condensate in the winter (you are talking about the coil in the air handler, right?). Is there a trap in the drain line? Generally there doesn't need to be ... unless it is connected to your sewer/drain line. Is it possible to connect it to your sewer line somewhere? Trying to think outside your box a bit. Connecting it to the sewer might help keep some warm air in it ... but you also will then need the trap (don't want sewer gas circulating into the air stream).

   The other response sounds right about the heat tape ... you could confirm w/ a quick call to the mfg.

3. 
   Jamwats | Sep 30, 2008 09:09pm | #6

   You may be able to eliminate most of that piping by using a condensate pump dumping it into a waste pipe.  That would keep gases from backing up into your unit.  The problem will be locating that pump in a location where it can't freeze.  Maybe you could locate it in some sort of insulated box in the attic or maybe even locate it in the house (pretty small unit).

   Jamie

4. 
   Tim | Sep 30, 2008 10:28pm | #7

   Suggestions:

   1. Move the condensing furnace to a location where it will not be subject to freezing temperatures. In addition to the freezing that you know has occured in the drain pipe, freezing has and will continue to occur in the secondary heat exchanger and/or the inducer housing. This will cause expensive, recurrent failures.
   2. Replace the condensing furnace with an appropriate non-condensing unit.
   3. Get the home and cell phone numbers of the incompetent hack that installed this unit in the attic and call them at any time day or night that the unit doesn't operate properly, as they should experience as much pain possible for such an error;> !