Using Low fan speed on Central heating system

Old 01-12-11, 10:24 AM
David Kantor's Avatar
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Using Low fan speed on Central heating system

Client wants to lower fan speed (doesn't like fan noise) on heating mode. Trane circuit board has chart for placing fan leads which DOES NOT include using the low speed fan tap. Any problems using it anyway? Will plenum overheat (don't think so in my opinion).
The board has three positions for the three (speed) wires from the fan: Heat, Park, Park. currently heat is using the middle speed wire for the fan.

Dont' want to create a safety hazard but want to help my client. Any thoughts?
Old 01-18-11, 04:37 AM
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The only way to test and be sure is to measure the temperature difference across the heat exchanger and make sure that its within the manufacturer's specs. You can try it anyway but if it gets too hot the furnace is going to shut down on high limit.

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