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-   -   Rheem Classic 90 Plus furnace not heating well: Limit Switch Open (https://www.askmehelpdesk.com/showthread.php?t=451091)

  • Feb 24, 2010, 07:06 AM
    mich100
    Rheem Classic 90 Plus furnace not heating well: Limit Switch Open
    Hi,

    First off, many thanks to all who frequent this forum and help each other out. It's really appreciated.

    I have a "Rheem 90 Classic 90 Plus" gas furnace. For the last few days it has not been heating the house as well. It works for a short time then quits, then comes up again, and quits, and so on.

    The blower sound is louder than usual. Also, it makes funny sounds. Here's a recording.

    The status light indicates: Limit Switch Open.

    Thanks for your help! A picture of the furnace:
    http://public.blu.livefilestore.com/...rnace_view.JPG
  • Feb 24, 2010, 09:01 AM
    johnair77

    Blower mtr. Bearings are bad orrrr one of those two capacitors I see is bad, try spinning the mtr. Wheel to get it going.. if it comes up to speed and runs normal you have bad bearings
  • Feb 24, 2010, 11:05 AM
    mich100
    Quote:

    Originally Posted by johnair77 View Post
    blower mtr. bearings are bad orrrr one of those two capacitors I see is bad, try spinning the mtr. wheel to get it going..if it comes up to speed and runs normal you have bad bearings

    Thanks for your reply. I tried spinning the motor wheel and it spins fine. How do I identify the bad capacitor?
  • Feb 24, 2010, 12:54 PM
    johnair77

    You must spin the mtr. While it is growling and trying to start, if it comes up to speed and runs nomal the run capacitor is probably OK, also try to move mtr. Shaft (while unpowered) up and down to feel any slight movement, in and out or thrust movement is OK, but up and down play reveals worn bearings and causes shaft to be magnetized in one spot and growl and humm..
  • Feb 24, 2010, 01:00 PM
    johnair77
    You would need a mfd tester for the capacitor, just buy another PROPER sized capacitor with the CORRECT mfd. Rating for your mtr. And try it.. you can always use it with the new mtr. If the bearings are bad on this one.

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