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Heating, Air Conditioning, Fridge, HVAC/the general 90 total furnace contr. 50a50-112


hello, my furnace is about 17 years old by intercity products and i had 4 flashes on the furnace which indicates an open limit switch. we replaced the switch in the motor blower, and the one that is where the heat pases through. however the computer continues to flash 4 times. when we repalced the limit switch it worked for a day then cold air came out. i dont want to call another company that wants to just replace the limit swich then it works and quits a day late. whant should i do. thanks

There may not be anything wrong with the limit switch.  The switch may be doing what it suppose to do.  High limit can be caused by different things, but I would start with air flow.  Check for dirty filters and anything else that will restrict air flow.


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Craig HVAC Expert


I have been in the HVAC field for the past 18 years. I can help with most HVAC questions. I work on commerical buildings for the most part, and have yet to find anything I could not troubleshoot and repair, when repairable. I work on small 1 ton units to a 2500 ton chiller. Troubleshoot air flow, elect, and control problems. I attend regular classes to keep up with the latest and greatest.


I work on commerical sites, hospitals, gov't buildings. I can troubleshoot just about anything in the HVAC business.

5 years trade school, VFD training classes, Liebert factory training, some York and Trane factory training.

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