Troubleshooting high limit switch problems on furnace
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11-27-16, 10:59 AM
Join Date: Nov 2016
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So possibly three problems:
1. The filter is too restrictive
2. The return ducts have some internal obstruction
3. The return ducts are too small
I tried a fiberglass filter and with that in place, I still tripped the high limit switch.
So now, I have put the filter back into place and removed the blower door and put another filter over the blower door opening. My furnace is in my basement, so it's pulling air from the bottom of the house (should be the coldest air) and the basement registers are closed. So theoretically, the furnace should work fairly efficiently as the general airflow should be coming down from the upper floors to the basement.
1. The filter is too restrictive
2. The return ducts have some internal obstruction
3. The return ducts are too small
I tried a fiberglass filter and with that in place, I still tripped the high limit switch.
So now, I have put the filter back into place and removed the blower door and put another filter over the blower door opening. My furnace is in my basement, so it's pulling air from the bottom of the house (should be the coldest air) and the basement registers are closed. So theoretically, the furnace should work fairly efficiently as the general airflow should be coming down from the upper floors to the basement.
