[RFI] Trane furnace RFI solution

j. viele w8jv at yahoo.com
Sat Mar 7 19:29:13 PST 2009

I recently traced RFI that was constant and band wide, expecially on the lower bands, to my newly installed Trane XV95 furnace.  The S-9 interference appeared to be present whenever the "inducer" variable speed DC motor was running.  I was instructed by the furnace installer to allow motors to run continuously to improve air circulation since an electrtonic air filter option was also installed.  The RFI was so severe that I was forced to turn off the furnace whenever I wanted to chase DX on 160 or 80 meters.  I contacted Trane customer service via e-mail and was informed the next day they provided a kit described as KIT14688 that could be installed by a furnace tech from the dealer who did the initial installation.  I contacted the dealer, in my case Clayton Heating in Youngstown, Ohio, and within a week they called saying the kit was in hand and they made an appointment for a tech to install it.  The installation took less two hours and was covered by
 the warranty since this was a new furnace.  The unit appeared to be a filter in a metal enclosure and several shielded cables.  The tech said this was their third installation.  I am pleased to report that the RFI on all bands has been cut to nearly zero.  There are, mysteriously, a few frequencies on 17 meters where th RFI still is evident but nowhere else.  Since I spend most of my operating time on 160 and 80 CW this has not been a problem.  I do have some snap-on ferrites that I may install on the motor leads and will let you know if it helps keep down the slight RFI on 17 meters.  W8JV

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