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				Furnace exhaust fan question
				Posted: Sat Jan 02, 2010 9:25 pm
				by manleygt
				I have a 1995 Intertherm furnace in my home.  I noticed this morning that the ventilation fan keeps kicking off and on. At times it does this every 5 seconds and then others it cycles like "normal".  I switched thermostats to see if it was that since we recently switched to a digital model.  It made no difference.  In addition, it will do this when the thermostat is set to a cooler temperture than what it really is and the furnace is not even producing heat.  It does it when it is at a cooler temp too.  Any ideas?
			 
			
					
				Re: Furnace exhaust fan question
				Posted: Sat Jan 02, 2010 11:00 pm
				by rmurray
				There are others here with more repair experience than I have, but it sounds like a common problem that Intertherm has had in the past. The cycling of the blower fan is controlled by a temperature limit switch inside the heating box of the furnace. It is not uncommon for limit switches to malfunction. A quality furnace repair person should be able to test and diagnose this problem and repair at a reasonable price. This part is probably available at the parts store listed on this web site just below this post. If I sound way wrong, I trust others will help correct me.