Original message
| rick31797
 |  "Primary limit switch"
, posted Tue 19 Feb 22:56:  
I did a search and think this switch needs to be replaced...doesnt look that hard to change.
The furnace will start up run for 5 mins or so.. then the burner and Inducer will shut off and 15 secs or 30 sec will go by .and it will start back up and run to finish the cycle>
The air filters are clean and i just had a new Gas Control valve put in, and they socked it too me.. That part alone was 250.00 and i see the same one on Ebay new for 120.00 >.Oh well.
I am not sure how long this has been going on.
Its a Clare High effency gas furnace.
I see when it recycle and starts up the Control unit flashes 2 times.
What else can cause this problem.
Rick
[this message was edited by rick31797 on Tue 19 Feb 22:58] |
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| rick31797
| "Re(1):Primary limit switch" , posted Wed 20 Feb 07:34:
wow i didnt realize all this could be wrong..I realize they stopped making these furnaces. A bad choice of Furnace.
This is a Clare Compact 90, and is 12 yrs old>> and this is the first of any problems.. But this furnace has never been cleaned..The coils have not be done
Cleaning the Coils...Is that hard to do..what do they use to clean them??? and if these have not been cleaned... in 12 yrs are they no good.
No duct work is blocked and air filter is clean and in the right way.
I did measure the air temperture rise.. and got a figure of 72 to 90.
which according to the book is too high. At the plenum it gets up to 158 degres at about 2 feet up from the furnace.
The book says it should be 35-65.. rise between cold air and hot air.
So it looks like it could be a number of things causing this.. but cleaning should be the first step.
With a furnace only 12 yrs old i hate to replace it already.
The primary Switch >>>>>>seems that it is doing its job and shutting down the furnace because of heat.
Rick
[this message was edited by rick31797 on Wed 20 Feb 09:10] |
| northernfitter
| "Re(1):Primary limit switch" , posted Tue 19 Feb 23:57
The Clare hi eff furnaces are famous for plugging up at the secondary coil. It's got fine fins and if you dont do a great job keeping it clean they plug up pretty bad. It depends though on what type of clare it is and how old. Either way you also need to know that that company is now out of business do to what was a really poor product design for quite a few years. If this is a megasave there is a port above the ventor motor on a lot of them that allows access to the secondary coil. If you have a high efficiency clare thats under 10 years old or less and tall and slim best of luck on it they were plagued with problems and honestly you would be best off to replace it or get ready to have yearly occurances like this one.
14years as a service tech in Ottawa and the valley. www.reliableheating.ca. For furnace manufacturer ratings go to
http://www.consumerreports.org/cro/appliances/heating-cooling-and-air/gas-furnaces/furnaces-repair-history-205/overview/index.htm?resultPageIndex=1&resultIndex=1&searchTerm=furnace
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| Houston204
| "Re(1):Primary limit switch" , posted Tue 19 Feb 23:48
If it trips on high limit, it could be a dirty evaporator coil, duct restriction, bad heat exchanger, fan motor, capacitor, fan control.
Measure the temperature rise across the furnace and compare it to the rated rise on the furnace nomenclature.
"Tip of the Day" Remember to remove power first.
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