PDA

View Full Version : Rheem Classic 90 Plus furnace not heating well: Limit Switch Open


mich100
Feb 24, 2010, 07:06 AM
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 (http://public.blu.livefilestore.com/y1p9RJN5FCDP2m06Z5MZYGT_iJeyqi5KTOOj5gg1n06eGNEodj P7eQbuCWp53pAfJV1bbM2nyJbg7vrgrVCN8f8sw/furnace_sound.mp3?download).

The status light indicates: Limit Switch Open.

Thanks for your help! A picture of the furnace:
http://public.blu.livefilestore.com/y1paRQdKoETMu8uBYDtzdpsqNh4w6tmJulWYNl4Ff2Q3GfCH5R FKoTzJY94pJXO48M7HKVXizFH5NAFebebu0eRNQ/furnace_view.JPG

johnair77
Feb 24, 2010, 09:01 AM
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

mich100
Feb 24, 2010, 11:05 AM
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?

johnair77
Feb 24, 2010, 12:54 PM
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..

johnair77
Feb 24, 2010, 01:00 PM
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.