[CQ-Contest] [MWA] New furnace... off topic, but related to contesting

[Sean Cavanaugh]

I've seen a lot about this problem with Trane furnaces, but I've got a 
similar problem with my new Lennox G71MPP. I haven't found any others 
with the same problem with this furnace online yet, so I may be an 
isolated case.

I'm currently waiting for some ferrites to come so I can try to shut it 
up. I put some unidentified ferrites I had lying around on the AC and 
motor leads and got a modest improvement (1-2 S units), so I'm hoping 
some more/proper mix ferrites help.

There's noise from S5 on 30M to S9 on 10M when the furnace is running. 
It's worst on 20 and 10. Now that the temp is down to -30C at night 
here, the thing runs almost constantly so I can do very little on the 
higher bands.

--
Sean - VA5LF

On 12/10/2009 4:12 PM, Greg Fields wrote:
> Bob,
>
> I put in a new Trane furnace last year that caused S7 noise. First I had
> help from Ron N0AT finding my noisy power pole then I had an S7 noise that
> kept coming and going before I figured out I had another noise problem. Here
> is what I posted to the MWA last March.
>
> It took me two months to figure out what the intermittent noise source was.
> It finally dawned on me one day when I had the radio on as I worked on some
> paper work. Sure enough, the noise came on but, I realized it coincided with
> my new furnace going into it's heat cycle. I then waited until the next
> heating cycle of the furnace to start and sure enough, the noise started
> again. I quickly threw the power switch on the side of the furnace and guess
> what? The noise went out instantly!
>
> A quick search of the Internet for my new Trane XV95 furnace picked up posts
> on eham documenting the same problem. Apparently the inducer motor, which is
> used to vent gases, is the culprit. I found a very good write up on it by
> N9SZ at:
>
> http://homepages.udayton.edu/~zabarnic/RFI.html
>
> I emailed my sales rep from Total Comfort who got the fix from Trane, which
> is a filter of some kind, a new wire for the inductor motor, and two split
> beads. The fix and installation was provided under warranty so it didn't
> cost me a thing, which made me very happy. However, after the fix was
> installed last Tuesday I noticed no difference. I took the next step and
> ordered type 43 split beads from Surplus Sales of Nebraska as N9SZ had. Like
> N9SZ I took 14 split beads this morning and put them all over the wires in
> the furnace.
>
> I am happy to report the noise is gone now. I don't know if just the split
> beads would have fixed it or if I needed the Trane fix and the split beads.
> The bottom line is my noise is gone and I am hoping next Fall's contests can
> be heard in the clear without straining to hear through some sort of noise
> again. If you get a new high efficiency furnace from Trane make sure you
> insist they put in the RFI fix when it is installed.
>
> 73,
>
> Greg K0OB
> ----- Original Message -----
> From: "Robert Chudek - K0RC"<k0rc at citlink.net>
> To: "Minnesota Wireless Association"<mwa at w0aa.org>;
> <cq-contest at contesting.com>
> Sent: Thursday, December 10, 2009 3:18 PM
> Subject: [MWA] New furnace... off topic, but related to contesting
>
>
> The serviceman just left after installing a new furnace controller. I am
> considering replacing the P.O.S. furnace that has kept the repair department
> in an unforecasted revenue stream the last 5 years.
>
> There has been advancements in technology in the past 17 years. This
> includes a variable speed DC blower motor upgrade from a multi-speed AC
> motor. Does anyone have any experience in the newer technologies in regard
> to my HF gear? Specifically, a variable speed DC motor sounds like it might
> be an RFI generator.
>
> 73 de Bob - KØRC in MN
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