[RFI] HVAC

[Dave (NK7Z)]

Think of a variable speed fan controller as an automatically controlled, 
dirty 500 watt square wave generator, connected to a long non twisted 
wire, running a motor...  They are quite noisy...

I have a neighbor that has one, (probably 70 feet from my antenna), and 
he used to run it 7 minutes on, 7 minutes off to clean his home air.  I 
asked him if he could change that to as needed, and I now have 17, 15, 
12, and 10 back, when it is not running, which is most of the time...  
He has two Carrier units, and they make zero noise.

His Mitsubishi unit is the culprit in the RFI generation.  The model 
number is:

SUZ-KA12NA

The installer has no idea of what RFI is...

73, and thanks,
Dave (NK7Z)
https://www.nk7z.net
ARRL Volunteer Examiner
ARRL Technical Specialist, RFI
ARRL Asst. Director, NW Division, Technical Resources


On 11/11/24 08:40, Dan K2YWE wrote:
> Thanks Jack.
> Do your units have variable speed or multi-speed fan control?
>
> 73, Dan
>
>
> On Mon, Nov 11, 2024 at 11:10 AM Jack Ference <jackference at gmail.com> wrote:
>
>> Hi Dan,
>>
>> Both Frank W3LPL I have had good luck with Carrier. He replaced one unit
>> as nd  replaced two a few years apart.
>>
>> I bonded the cabinet door to the sides, installed a powerline choke on the
>> power to the blower motor and installed a coil of wire choke around the
>> thermostat wires.
>>
>> I opted for one step down from the highest efficiency units so the
>> compressor had switched settings rather than variable settings  controlled
>> by electronic circuitry.
>>
>> Carrier was aware of my concerns and supplied the documentation for the
>> fixes. They happened to be the same fixes I did on my first unit replaced.
>>
>> Jack W3KX
>> Sent from my iPhone
>>
>>> On Nov 11, 2024, at 10:56 AM, Dan K2YWE <dan.k2ywe at gmail.com> wrote:
>>>
>>> I'm need to replace my 25 year old HVAC with a new oil furnace and AC
>>> system.
>>> EMIis a great concern. It's a small house and efficiency is of little
>>> importance.
>>> What are the recommended brands and/or models?
>>>
>>> 73, Dan
>>> _______________________________________________
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>>> RFI at contesting.com
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