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  1. #1

    Question

    Love this site, I've learned a lot just reading. I'm getting bids for a new furnace and AC in my rambler (yes, the late 50's model shoebox.) Since I'm in Minnesota, I figure the high efficiency furnace is the better option, with maybe a 13 SEER AC unit.

    I'm still wavering on variable speed fans and which brand, Lennox, Bryant or Trane. From what I've read here, any of those brands should be fine. But one thing I've been told bothers me.

    One salesman said that the high efficiency furnace exhaust vents A) freeze over unless you inspect them daily and B) attract small animals to come in and die, and the vents cannot be covered in any fashion! This guy also said that the PVC pipes would be sticking out about a foot from the house (and had photos!)

    Now this guy was real high pressure and he is definately NOT getting my business (despite doing a manual J calc, about the only thing I liked about him), but I am quite concerned that I may be stuck with a furnace that will never allow me to leave for a day (or even a week, as another dealer told me. Funny, they were both Lennox dealers.)

    So how about it, pros? Do the high efficiency furnaces have exhaust vent icing issues? If there is an issue, is it specific to Lennox, or do all models have the same problem? Or was this just a line to try to push an 80% unit on me?

    Thanks for all the info on this site!

  2. #2
    Join Date
    Jan 2003
    Location
    Kansas City
    Posts
    1,478
    90% furnace venting issues are similar with most brands, but icing issues are usually due to improper installation. I would never recommend a device of any kind for a home that needed daily attention and you have to believe that a furnace manufacturer would not expect you to buy one. We have very few issues with venting if furnaces are vented properly. Sometimes, a wasp nest ends up in the intake and has to be cleared, but this isn't a constant problem. This will usually happen in the summer and be noticed when the furnace is first turned on...like during maintenance.

  3. #3
    Join Date
    Dec 2002
    Location
    Rochester, MN
    Posts
    5,304
    LOL wow.. Where in MN are you from?? I am in Rochester.. Those Lennox guys must be scared of the 90's???? I'd look at someone else.

    The only time I've had problems with ice build in in the vent is

    -Screen was used on the intake (a foggy cold winter night)
    -Intake was too low to the ground.
    -the exhaust was put in wrong (blowing down to the ground) and the intake was sucking up high.


    As for animals, I had not had that happen to me for a service call..


    Trane has a nice BAYVENT that pretty much makes it looking good on the side of the home.

    Also, if the white PVC bothers you, it can be painted.

    Go variable speed.. You'd be glad you did.


    Check with your gas company (Xcel) and see what type of rebate you can get.. I got $200 from Aquila.

    Also 13/14 SEER is about all you want to go for in MN.

  4. #4
    I see you had a salesman and not a tech at your home.

    The only furnace I would recommend you going with would be a high efficient furnace!!!

    If properly installed and maintained, you will have years of reliable performance!

    The venting doesn't have to be a FOOT away from the home and you can install SS (stainless steel) large screens in the PVC piping.

    There are little concerns with freezing and rodents, if the piping is properly installed.

  5. #5
    Join Date
    Apr 2004
    Posts
    7,680
    Well, the screen is one way to make it freeze, even with 1/2" screen.

  6. #6
    Join Date
    Sep 2001
    Location
    Vancouver Canada
    Posts
    996
    I usually put a heavy piece of fishing wire through the vent outlets to stop any birds flying in. I have seen several units with birds in the inducer fan but other than that I have not seen any other animals (wasps excluded) in the vents. As for icing if the piping is installed as per manufacturer specs and sloped correctly it should not be an issue.
    "Go big or Go Home"

  7. #7
    Join Date
    Jan 2004
    Location
    Lancaster PA
    Posts
    66,807
    You can use a concentric vent, its only a couple inches deep, and they look nicer then the 2 pipes.

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    How many times must one fix something before it is fixed?

  8. #8
    Join Date
    Jul 2002
    Location
    St Paul, Minnesota
    Posts
    3,468
    Mice nest in intake of Lennox Pulse furnace. Came all the way in to inducer motor and died after birth along with mother. Solution: style of house limited location of pipes. Homeowner then landscaped with some stones and bricks which createda path right up to pipe, mice walked in.

    Bird in inducer wheel-dead, head crushed. Homeowner liked birds enough to put a 4'x4' covered bird feeder about 10' from pvc location. Birds would land in shrubs, dumbs ones went spelunking two years in a row. HO moved feeder far away and problem went away.

    Bird nest in intake pipe. Exit of pipes was 10' off of ground on front of house. House one block from White Bear Lake, few trees around. Used nitrogen and "blew" nest from house to middle of yard. 2nd time this happened. I recommended removing pipe or doing gooseneck, don't know what final solution was. I never found out why bumblebees liked Pulse units. Almost always remove a couple from the intake chamber during service calls. They don't do any harm, just get in there and croak. They are ground nesters tho.

    I've removed birds, squirrels, and nests from chimneys of old style furnaces and boilers. Some birds sit on top and get overcome with exhaust, fall in and die.

    The number of service calls for iced over pvc pipes is not that common but it does happen. Worst time is with a large snow fall or when drifting happens. Homeowners are not always aware of what those pipes do and even blow snow up against them. Rare but it happens. Another time is when we get that type of morning where it is below freezing and damp. Hoar frost can build up. Also, when an intake is too close or downwind from the exhaust, or in a corner. Intake frosts inside of the pvc from sucking in moist exhaust air. Finally completely blocks pipe.

    I have removed screens that froze over and stopped the unit from running. Some manufacturers say they are ok. If used, the screen should be at least 1/2" squares and the squares should be angled so they look like an 'X'.

    Trane has a nice bayvent. Worked on a couple of those three years ago. Seems our installers didn't think it mattered if they got assembled tight. A gap in the two pieces caused a water buildup in this space and the ice grew like a glacier till it blocked the vent.

    I have seen pvc that got knocked loose and the homeowner knew about it but didn't think it mattered until one night the unit would not keep up. It would start and stop, then go into lockout. Found out that the unit was intaking the exhaust and couldn't run due to lack of oxygen. So why not check an A/C prior to the season and a furnace piping regularly? Kids put rocks in them, mothers put easter eggs (plastic) in them (yep, sucked it right into the furnace top where there is a screen. It blocked air flow. Renters hang clothes from gas pipe and pvc pipe. During first few run times of furnace do your own inspection. No water should drip from exhaust pipe connections and slope should be noticeable, 1/4in per foot at least. Specs are in manual.

    If I had a high efficiency unit, I would probably want to build a 2' x 2' screened box over mine. I would probably at least cover the pipes during the off season and remove prior to fall check up, just like I would lay a piece of 3/4" plywood over the top of a condenser during the winter. I would look into a Trane and a good company to install it but I think Lennox and Carrier are also good units. I would go with extended warranties and I would read the manual cover to cover seven times too.

    I would also make sure that the pvc inside of the home does not have any sags and does not exceed the manufacturers specifications. I have been out on a few of these problems also. Amazing how much water collects when it looks like it 'only sags' a little. I have pulled debris out of the Lennox rubber exhaust boot more than a few times each winter. And, wonder why some engineer decided that he could reduce the size of the drain hole that much just to insert a nickel piece of plastic to connect a hose to. Do they not lay awake at night and rethink their days activities? They should.

    Maintenance is your responsibility and if it means that you have to check doors and water faucets etc, before you leave for vacation or trips, so be it. Add furnace and water heater to your list. Remove shrubs from area of pvc or keep them far enough away. Get used to 'seeing' problems before they hit your pocket book.

    I have seen some winters where there is a spike in service calls due to no gas. Seems under certain conditions the outside gas meter regulator diaphram 'freezes up'. Only a gas company technician can tell you exactly why. Last one was I believe three yrs ago. Many calls over a two day period when temps went down over twenty below. (Pays to keep this in mind).

    Keep bedroom windows cracked open an inch or so during the winter.

    Mn born and raised. East metro serviceman for ten years.

    Why not follow up with what you chose and how the install went?

    [Edited by MikeJ on 09-07-2005 at 09:12 AM]

  9. #9
    Originally posted by MikeJ
    I have seen some winters where there is a spike in service calls due to no gas. Seems under certain conditions the outside gas meter regulator diaphram 'freezes up'. Only a gas company technician can tell you exactly why.

    Keep bedroom windows cracked open an inch or so during the winter.
    Freeze ups due to moisture.

    And the last comment is only masking a real problem. There should be no reason for a window to have to be open!

  10. #10
    Join Date
    Nov 2001
    Posts
    1,874
    LENNOX,

    I would recommend a G61mpv, 2stage 90% gas furnace rated at 94%.
    And scale back on the a/c, install a 10 or 12 seer.
    A 10 seer unit with the variable speed drive furnace will give over 11 seer.

    Your not in a high a/c climate,
    You use a/c but not like some places in the us, that rely on it 6 to 9 months.
    They would be more apt to need a 13 or 15 seer.

    You'll save enough on the a/c to upgrade to the variable speed 2 stage furnace.

    You'll get more use from the heat, then you will the a/c.
    So focus on the cheaper gas and more comfort that the G61 will provide.

    Just my 2 pennies,
    Now I'm sure I'll be blasted.
    If you try to fail, and succeed.
    Which have you done ?



  11. #11
    Join Date
    Jan 2004
    Location
    Lancaster PA
    Posts
    66,807
    Ok, I'll bite, why keep the bedroom window open an inch or 2.

    Kinda defeats the purpose of buying better windows.
    Contractor locator map

    How-to-apply-for-Professional

    How many times must one fix something before it is fixed?

  12. #12
    Join Date
    Apr 2004
    Posts
    7,680
    defeats the purpose of having a furnace where you live!

  13. #13
    Join Date
    May 2004
    Location
    Rapid City, SD
    Posts
    7,403
    Open the windows so you don't get hot from your trusty furnace running ;-) lol

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