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  1. #14
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    Quote Originally Posted by big sky hvac View Post
    I personally would never run a condensate pump drain line outside, there is always a better way.
    Care to share?

  2. #15
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    Jun 2009
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    I have the same problems. Some contractors say don't do it. One says he can put in a pump, run a hose up over a doorway, through the wall into the laundry room, and then into the washer drain. Going out the wall would be a much shorter run, but would allow the potential of freezing. I've wondered, why not just put a thermostatically-controlled heat tape on the pipe where it exits?

  3. #16
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    Quote Originally Posted by garya505 View Post
    I have the same problems. Some contractors say don't do it. One says he can put in a pump, run a hose up over a doorway, through the wall into the laundry room, and then into the washer drain. Going out the wall would be a much shorter run, but would allow the potential of freezing. I've wondered, why not just put a thermostatically-controlled heat tape on the pipe where it exits?
    Well, I believe that most furnace mfgs say to insulate and apply self regulated heat tape (5-6W/ft) to the entire condensate system, so that should be a given. Thing is, you cant use heat tape on vinyl tubing, which is what most folks use to run from pump to drain.

    Some say to use metal (such as copper) for the last run so you can apply heat tape, but condensate is acidic and the metal will corrode. So run the vinyl through PVC and heat tape the PVC. Problem with that is heat tape & PVC aren't a good thermal match already and the vinyl would probably actually act as an insulator (of course the heat tape + vinyl rule may still apply).

    So looks like one needs to have as much as the condensate line plumbed in PVC (which I believe needs to be 3/8" ID (same as the vinyl) or the pump's longevity is compromised). Then try to get the condensate's exit plumbed into some conditioned space so you don't have to worry about the end freezing. But I don't know.

    I've also heard of folks running the condensate through something to lower its freezing point, such as a salt bath, before it exits. But that means you have to check that at least once a season, and stuff may not like the salt water.

    I've had 3 contractors on site for install quotes and they all had very different ideas on the condensate system.

    Oh, and don't forget about a secondary drain pan, drain and alarm in case some other failure of the furnace's condensate system occurs, such as the furnace's condensate trap leaking, etc..

  4. #17
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    Jun 2009
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    Albuquerque NM
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    Quote Originally Posted by b26440510 View Post
    Well, I believe that most furnace mfgs say to insulate and apply self regulated heat tape (5-6W/ft) to the entire condensate system, so that should be a given. Thing is, you cant use heat tape on vinyl tubing, which is what most folks use to run from pump to drain.

    Some say to use metal (such as copper) for the last run so you can apply heat tape, but condensate is acidic and the metal will corrode. So run the vinyl through PVC and heat tape the PVC. Problem with that is heat tape & PVC aren't a good thermal match already and the vinyl would probably actually act as an insulator (of course the heat tape + vinyl rule may still apply).

    So looks like one needs to have as much as the condensate line plumbed in PVC (which I believe needs to be 3/8" ID (same as the vinyl) or the pump's longevity is compromised). Then try to get the condensate's exit plumbed into some conditioned space so you don't have to worry about the end freezing. But I don't know.

    I've also heard of folks running the condensate through something to lower its freezing point, such as a salt bath, before it exits. But that means you have to check that at least once a season, and stuff may not like the salt water.

    I've had 3 contractors on site for install quotes and they all had very different ideas on the condensate system.

    Oh, and don't forget about a secondary drain pan, drain and alarm in case some other failure of the furnace's condensate system occurs, such as the furnace's condensate trap leaking, etc..
    It's all this kind of stuff that makes me wonder if the 95% furnace is worth the trouble and extra expense. Some days I just figure, screw it, I'll just get the 80% furnace.

    Oh, and my furnace is in an unheated garage, which has the potential of dropping to freezing. That means if I go out of town in the winter I have to leave the furnace running to avoid having the water left inside the furnace and pump freeze, right?

  5. #18
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    Jul 2010
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    Quote Originally Posted by garya505 View Post
    It's all this kind of stuff that makes me wonder if the 95% furnace is worth the trouble and extra expense.
    Well, since the price of fuel is only sure to continue to rise, I think its a small price to pay upfront. Its really a matter of how much time one invests into finding out the best solution for their situation.
    Quote Originally Posted by garya505 View Post
    Oh, and my furnace is in an unheated garage, which has the potential of dropping to freezing. That means if I go out of town in the winter I have to leave the furnace running to avoid having the water left inside the furnace and pump freeze, right?
    hmm, no idea. I would guess that if the pitch is correct, that most of the condensate in the furnace will be drained out to your pump before its shut off. I would think the furnace mfg would provide sufficient room for whatever condensate would be left in the furnace that was off to freeze without doing damage, but who knows. Thats where the experience of the HVAC company and their knowledge of that furnace comes into play.

    Of course, keep in mind that the mfg instructions I've seen say to apply the heat tape to all of the condensate system, including the furnace's condensate trap.

  6. #19
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    Quote Originally Posted by b26440510 View Post
    Its really a matter of how much time one invests into finding out the best solution for their situation.
    Now that is something I know something about!

  7. #20
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    Feb 2007
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    999
    Quote Originally Posted by 02powerstroke View Post
    need to know if the furnace has a condensate pump in it or if it is gravity fed... if it is gravity then you can't go vertical with it... must be sloped... they do make condensate pumps, which could be used in this situation... you need to be sure that the equivalent foot of head the pump can provide isn't exceeded
    Exactly. When my system was installed, I asked to have the condensate pumped up (about 14 feet) and over (about 20) to a laundry room sink. Contractor: 'no problem'.

    As far as having to leave the furnace on in an unheated garage, wouldn't you need to keep the furnace on anyway to protect your household plumbing?

    For the PROs, would there be enough heat migrating from the burner/heat exchanger areas to keep everything flowing?

    Amp
    Last edited by ampulman; 08-02-2010 at 01:49 PM. Reason: added postscript

  8. #21
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    May 2010
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    SF Bay Area, CA
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    Quote Originally Posted by b26440510 View Post
    hmm, no idea. I would guess that if the pitch is correct, that most of the condensate in the furnace will be drained out to your pump before its shut off. I would think the furnace mfg would provide sufficient room for whatever condensate would be left in the furnace that was off to freeze without doing damage, but who knows. Thats where the experience of the HVAC company and their knowledge of that furnace comes into play.

    Of course, keep in mind that the mfg instructions I've seen say to apply the heat tape to all of the condensate system, including the furnace's condensate trap.
    My Bryant instructions say to wrap the furnace internal condensate trap w/ heat tape, if it can be exposed to <32* weather and then 1 wrap of heat tape per foot of drain pipe.

  9. #22
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    Quote Originally Posted by ampulman View Post
    Exactly.
    As far as having to leave the furnace on in an unheated garage, wouldn't you need to keep the furnace on anyway to protect your household plumbing?
    Amp
    The garage is vented to the outside for combustion, and this vent would need to be retained for the water heater. The house doesn't get that cold even with the heat off.

  10. #23
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    Sep 2006
    Location
    Montana
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    Quote Originally Posted by b26440510 View Post
    Care to share?
    If you're in a crawlspace, there are a couple different options for running the condensate line. You can run it into a sewer line, keeping in mind it should be trapped before going into the line. If you have access to the laundry room, you can come up through the floor behind the washing machine and use the drain for the washing machine. As far as worrying about the crawlspace freezing up, you can always choose to condition the space. Just cut a supply register in the trunk and open it in the winter. If you're dead set on pumping it outside, or have no other option than to pump it outside, you can run the pump drain line in 1/2" pvc, wrap it with heat tape and armaflex and hope that it doesn't freeze. With 90% furnaces in garages, the best thing to do is make sure that the garage is well insulated. You may even consider building a small "closet" around the furnace to help maintain as much of the heat to prevent freezing. The other alternative would be to install a unit heater and maintain 45*F in the garage to prevent freezing. The number one thing homeowners should remember when installing a 90% furnace in an unconditioned space such as a garage, have a regular tune up performed to help ensure that the furnace isn't going to shut down and freeze up. You should really be having regular maintenance performed on them anyway, but it's even more important in those situations.

  11. #24
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    Jun 2009
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    Albuquerque NM
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    Quote Originally Posted by big sky hvac View Post
    If you're in a crawlspace, there are a couple different options for running the condensate line. You can run it into a sewer line, keeping in mind it should be trapped before going into the line. If you have access to the laundry room, you can come up through the floor behind the washing machine and use the drain for the washing machine. As far as worrying about the crawlspace freezing up, you can always choose to condition the space. Just cut a supply register in the trunk and open it in the winter. If you're dead set on pumping it outside, or have no other option than to pump it outside, you can run the pump drain line in 1/2" pvc, wrap it with heat tape and armaflex and hope that it doesn't freeze. With 90% furnaces in garages, the best thing to do is make sure that the garage is well insulated. You may even consider building a small "closet" around the furnace to help maintain as much of the heat to prevent freezing. The other alternative would be to install a unit heater and maintain 45*F in the garage to prevent freezing. The number one thing homeowners should remember when installing a 90% furnace in an unconditioned space such as a garage, have a regular tune up performed to help ensure that the furnace isn't going to shut down and freeze up. You should really be having regular maintenance performed on them anyway, but it's even more important in those situations.
    I'm starting to think using a condensing furnace in an unheated space is "fraught with peril". Of course you can do it using some of these things to reduce the risk of freezing, but I have to wonder if it's worth the risk. Maybe condensing furnaces should be used only where you know for sure you can prevent freezing temperatures.

  12. #25
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    Sep 2006
    Location
    Montana
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    Quote Originally Posted by garya505 View Post
    I'm starting to think using a condensing furnace in an unheated space is "fraught with peril". Of course you can do it using some of these things to reduce the risk of freezing, but I have to wonder if it's worth the risk. Maybe condensing furnaces should be used only where you know for sure you can prevent freezing temperatures.
    I personally am very hesitant about putting a condensing furnace in a garage, especially if it's not insulated. I've put several condensing furnaces in crawlspaces and have had next to no problems. That doesn't mean you couldn't have problems in crawlspace installs, but I don't worry about them like I do with garage or attic installs. If proper measures are taken, they can still be done. It does turn into a little "roll of the dice" though.

  13. #26
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    Aug 2010
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    11
    My situation is that the only drain is not a floor drain, instead the drain is in a laundry sink that is one floor up and on the other corner of the house from the furnace. Once the condensate line gets to the laundry room (10 feet up and 50 feet over), the line would again have to go up several feet before it came back down into the laundry sink.

    One contractor recommends a condensate pump, another contractor says it is too far. The line would have to be snaked in the basement ceiling to get to the laundry room, so, even if it works, I am concerned about a potential leak later. Is this a legitimate concern, or is it very unlikely. Thanks.

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