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zinpoe@msn.com

new member

2 post(s)
posted on 4/7/2007
My wife and I bought this house in October and the Honeywell T-stat and Rheem furnace have been working fine...until yesterday.  I have the t-stat set to 68, but the temp in the house is a balmy 60!  The furnace (Rheem Criterion from 1999) will kick on, the burners ignite but only for about five seconds.  Then they kick off while the fan continues to blow cold air.  If I turn the power off, then on, the furnace will start up but runs this same cycle.  My online searching leads me to believe it could be the limit switch.  I know nothing of furnaces but I do know that it is cold in my house.  Any help would be greatly appreciated.  I really do not want to call in a tech on a holiday weekend.  Thanks!
 
 
Replies [ post reply ]
tammyngabe1@att.net

senior member

45 post(s)
replied on 4/7/2007

what did the filter look like. was it really dirty? is it a pleated or a glass floss filter. if your limit is a high limit then that would mean your not getting enough air through the furnace then i would check to make sure your returns are not blocking air from getting to the furnace. because air is just being circulated through the furnace and picking up the heat from it. let me know if this helps


zinpoe@msn.com

new member

2 post(s)
replied on 4/7/2007

Thanks Tammyngabe.

I replaced the air filters (something I hadn't gotten around to doing since we moved in) and that seemed to do the trick.  Temp went right up to 68 and stayed there for a while.  Then it went back down to 65.  I played around a bit with the furnace and the OK LED light is giving me the "Open Limit Switch" code.  I assume this means I need to close the limit switch although I don't know how I go about doing that.  I have been all over the web reading forums and I am glad to learn that I am not the only one having this sort of problem.  Any advice on how I close the limit switch?  I think I have identified what it is, that's step one for me, but it doesn't readily look like something that is open or closed.

Thanks for your help.



tammyngabe1@att.net

senior member

45 post(s)
replied on 4/7/2007

it is probably your flame senser . it is a little rod next to the pilot that has a ceramic base its not sensing a flame get a small wire brush and clean it, not to much,stroke it a few times and then try igniting again and see what happens. let me know if this helps.


zinpoe@msn.com

new member

2 post(s)
replied on 4/8/2007

The filters were beyond dirty.  Solid gray with dirt, dust, and whatever else.  I bet they haven't been replaced in over a year.  Considering they are 30 day filters, they were well past their prime.

The furnace worked all yesterday afternoon and all last night...maintaining 68 and 62 degrees respectively.  Then when I got up this morning, 60.  Shoot!  Here I thought I was Mr. DIY Fix-It-Man!  So I took your advice Tammyngabe and diconnected the flame sensor.  Since the yellow flame LED was blinking you hit the nail right on the head with that suggestion.  I cleaned it up with a little steel wool and wouldn't you know it?  Solid yellow LED now, the burners stay on, and the temp is up to 64 already!  Sweet!

I hope this does the trick.  Thanks for your help!!!




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