See if the noise is there with the unit running in fan mode only. I had this
problem with a new install and had to add common mode chokes on the fan wires.
The blower uses a variable speed fan motor. You may need to do the same on the
compressor leads if the fan is not your problem.
Tom WB4JWM
On Saturday, September 5, 2020, 1:32:54 PM EDT, 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
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