replaced dryer vent now dryer is cold inside.

Discussion in 'General Appliance Discussion' started by SidecarBob, Dec 8, 2017.

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  1. Dec 8, 2017 #1

    SidecarBob

    SidecarBob

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    We have lived here for over 20 years and stuff put into the dryer at bedtime was usually still warm in the morning, even in February. This summer I noticed that the outside vent's plastic was starting to crumble so I replaced it with a similar large hood flapper with pest grill.

    Now if we leave the clothes in the dryer for an hour after it stops they are cold to the touch. The first time it happened I thought they were still damp but they are completely dry so I thought maybe the flapper wasn't closing properly but I checked and it is fine.

    Any ideas?
     
  2. Dec 8, 2017 #2

    Snoonyb

    Snoonyb

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    If the old exhaust hood had a flapper, it probably over time, became partially obstructed
    from lint build up, limiting it's operation and allowing heat to be retained.
     
  3. Dec 8, 2017 #3

    SidecarBob

    SidecarBob

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    There was some lint on the pest grill but there was only a small amount around the flapper. BTW: I replaced the original flexible duct with solid 2 years ago and there is no significant accumulation inside it as of when I replaced the vent.
     
  4. Dec 9, 2017 #4

    Snoonyb

    Snoonyb

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    It doesn't take a lot of lint build up to affect the temp. of the air in the duct. that being said, dryer cycles also have a cool-down cycle.

    Other than the selectors, dryers are fairly straight forward.
     
  5. Jan 4, 2018 #5

    Wuzzat?

    Wuzzat?

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    Elec. dryer?
     
  6. Jan 4, 2018 #6

    SidecarBob

    SidecarBob

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    Yep.

    We had some crappy windows that you could hear the wind whistling through replaced with decent ones since last winter and I initially wondered if that could be the problem but the furnace is a high efficiency propane burner with a combustion air pipe, the fireplace (that we haven't used in recent years) also has a combustion air vent. We do have bathroom fans that I think (hope) exhaust into the soffit. But we also have a whole house fresh air system and I expect that would more or less equalize the indoor air pressure.

    Something really odd: Since I first posted this I have noticed that it is not consistent.Clothes that have been left in the dryer when it is really cold out (below -20c) are usually about room temperature or warmer, the same as when it was warm outside. From what I have noticed it seems like the clothes in the dryer only get cold when the outside temperature is around freezing or a bit above. Curiouser & curiouser...
     
  7. Jan 5, 2018 #7

    Wuzzat?

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    W/elec., I thought one of the heater coils was warming the clothes because of a short, maybe running at 120v vs. 240v, and it stopped at the same time as the flapper valve replacement.

    Fronts coming in or leaving change the barometric pressure.
    I think now looking for a pressure difference may give some clue.

    A vane or propeller in the dryer duct may tell the story of air flow direction and when, but how to do? Finding a short length of clear 4" duct may be difficult.
    Or two barometers, one in & one out.
    Or
    http://www.google.com/search?client=safari&rls=en&q="differential+barometer"&ie=UTF-8&oe=UTF-8

    And, one dose of moving cold air may cancel out hours of non-moving room temp. air.
     
    Last edited: Jan 5, 2018
  8. Jan 5, 2018 #8

    nealtw

    nealtw

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    If it vents to the soffet area at least 6 ft of soffet needs to be solid, not vented. So moist air does not travel to the attic.
     
  9. Jan 5, 2018 #9

    tuffy

    tuffy

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    We bought a high end washer & dryer and was having the same issue as you so I went to the home depot and bought the Everbuilt wide mouth dryer vent kit for23.59 it exhausts twards the ground not allowing drafts to blow in made a hell of a difference has a single flapper that keeps the drafts out.
     
  10. Jan 5, 2018 #10

    SidecarBob

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    Re barometers &c: Or we could just not worry about it :p

    Re bathroom fans: All I know for sure is that they are in the ceilings and they do remove moisture &c from the bathrooms. The attic has blown in insulation well above the height of the joists, which I have successfully avoided disturbing for over 20 years (any ducts up there are covered). There are no visible vents anywhere. A couple of years ago I tried to figure out where it went so on a cold day I turned the shower in one bathroom on full & hot, turned the fan on and went outside to look for steam. When I didn't see any I got the ladder and looked in the attic but couldn't see any there either. The same for the other bathroom. Unfortunately the builder (who used to hang around the neighbourhood fixing stuff for people after he retired) died before I thought to ask him about it.
    I really should try again one of these days
     
  11. Jan 5, 2018 #11

    SidecarBob

    SidecarBob

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    The vent we have is a hood type with the open end down and a flapper, just like the one it replaced.
     
  12. Jan 5, 2018 #12

    slownsteady

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    Flapper may be lighter material than the last one. it might just be blowin' in the wind.
     
  13. Jan 5, 2018 #13

    Wuzzat?

    Wuzzat?

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    If your heating bill shows no difference before and after the new vent, don't worry.

    Divide the therms by the Heating Degree Days for each period.
     
  14. Jan 5, 2018 #14

    SidecarBob

    SidecarBob

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    There will be a big difference in the bill because it has already been colder out than we saw last February. Hopefully the replaced windows will moderate that difference a bit, though.

    I just dried some clothes and haven't taken them out yet so I checked the dryer and there was definitely a cold breeze entering through the lint trap as verified by laying a paper over the opening. I went outside and discovered that the flapper was stuck open. When I freed the flap it slammed shut and there is no breeze in the lint trap now.

    I didn't have my glasses on but there was something shiny where it was stuck so I think the culprit could be moisture condensing inside the hood when the dryer is running hot and then freezing & sticking the flapper to the inside of the hood when the dryer is cool near the end of its cycle. I have more to dry so I think I'll spray some silicone on first and see if that keeps it from sticking open.
     
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  15. Jan 5, 2018 #15

    SidecarBob

    SidecarBob

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    The dryer stopped so I checked the vent again and it closed properly this time.

    This is interesting. Before I started this thread I checked to make sure the flapper was closing and it was closed when I looked so I assumed that it was always closing. The daytime highs were still a few degrees above freezing then so maybe what was happening was that the vent stuck occasionally when it was colder out at night but it thawed & closed when the sun came out (its on a south facing brick wall that is usually warmer than the air when the sun is out - can you say "thermal mass"?). Maybe. I will continue to monitor this during the next few weeks to see if the silicone really did fix it.
     
  16. Jan 5, 2018 #16

    Wuzzat?

    Wuzzat?

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    That's why you divide by the heating degree days.
    http://www.degreedays.net/

    Miami welcomes you if you can stand the humidity & the drug dealers! :p

    So maybe you need a 10w 12v bulb in the duct near the flapper.

    "When you've eliminated the impossible, whatever remains, however improbable, is the truth."

    Do your water lines freeze and so people with welders have to come by and put some amps through the pipes?
     
    Last edited: Jan 5, 2018
  17. Apr 28, 2018 #17

    SidecarBob

    SidecarBob

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    The silicone spray seems to have done the trick. Since I sprayed the flap it has not stuck open and the dryer has not been cold inside.
     

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