Does your spectrum analyzer show tynes at 6.5 kHz, the spec switching
frequency of the inverter board? If so, you've nailed the source. If not,
keep looking and probing with the spectrum analyzer and a small magnetic
loop near and around the unit. Couple especially to the 240 vrms line
feeding the unit.
Another thought if the spectrum analyzer does *not* show 6.5 kHz switching
tynes: While I have a Carrier (not by choice!!), I had to have the
compressor motor starting capacitor replaced. The new one was smaller in
physical diameter and sat loose in the stainless strap (muffler clamp). It
rattled and produced all kinds of RFI. I just stuck a piece of aluminum
between the body of the capacitor and the strap to make a tight contact and
the RFI problem was solved.
Dave - WØLEV
On Sat, Sep 5, 2020 at 5:32 PM Karin Johnson <karinann@tampabay.rr.com>
wrote:
> Hello fellow RFI'ers:
>
> I just had a new AC system installed. Rheem model RP1748AJVCA.
>
> The noise floor on 40 meters just went up about 20 dB when the
>
> Unit is running in cooling mode. Turning it off via the thermostat
>
> Setting confirms this, as the noise floor drops back to ambient.
>
> Rheem calls this their Classic Plus Series RP17. It is 18 SEER rating.
>
>
>
> I have downloaded most of the available installation and data sheets that
>
> Are available on the internet.
>
>
>
> I suspect this is going to be a long involved project to get this unit
> quieted.
>
>
>
> My local installer and distributor isn't going to be of much help.
>
>
>
> I am pretty sure the major source of the RFI is the high power three phase
>
> Inverter board that drives the compressor motor in the outside unit. I
> haven't
>
> Actually verified this, but it makes sense as the only thing possibly
> causing these
>
> Levels of RFI would be a high power switching supply as in the inverter.
>
>
>
> My question for the group. Has anyone else had experience with this
> model??
>
> I have sent an email to Rheem but was unable to contact the appropriate
> department.
>
> Most of the access to the real technical folks is going to be hidden. I
> did
> manage to
>
> Get a phone number from one of the Rheem help lines regarding some issues I
> resolved
>
> With the thermostat (ECONET) programming. That might provide some more
> info, but
>
> For now being the weekend I will have to wait to call them.
>
> The Rheem outside unit with the compressor does have an impressive low pass
> filter board
>
> With toroids and other filter components applied to the main 240 volt input
> power feeding
>
> The inverter board. This indicates they at least thought about RFI. I
> have a Tektronix
>
> Spectrum analyzer and using the connected to a 40 meter vertical about 40
> feet away from
>
> The outside AC unit, you can see the spectrum of the noise generator
> (inverter).
>
> The Rheem documentation claims the switching frequency of the inverter is
> around 6500 Hz.
>
> Since I can't upload picture to the list, if you want to see the
> installation instructions from
>
> Rheem, which has pictures of the inverter board and the filters. Try
> searching for
>
>
>
> rheem_rp171748ajvca-InstallationInstructions.pdf
>
>
>
> It might be on the Rheem website, I forgot where I downloaded it.
>
>
>
> Anyway what I asked Rheem in an email was if there was any additional
> filtering kit available
>
> For this unit. My reply indicated that whomever answered my question was
> not technical
>
> Enough to know the answer. Probable because I am not talking to the right
> department.
>
>
>
> I have a lot of experience, being retired power electronics engineer in
> designing and debugging
>
> These types of system. Right now I am trying my best not to do anything
> that would void
>
> The warranty.
>
>
>
> Regards,
>
> Karin Anne Johnson P.E. K3UU
>
> Palm Harbor, FL
>
> _______________________________________________
> RFI mailing list
> RFI@contesting.com
> http://lists.contesting.com/mailman/listinfo/rfi
>
--
*Dave - WØLEV*
*Just Let Darwin Work*
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