[RFI] Lennox brand HVAC RFI experience

Jim Brown jim at audiosystemsgroup.com
Mon Jul 18 23:23:06 EDT 2022


While I've often advised to avoid variable speed motors, I do like 
Steve's advice IF, and ONLY IF, you have selected both a product well 
engineered to be RF quiet and a contractor who will do it right. I know 
Steve, and he's a serious engineer.

I also advise to never trust what anyone tells you about ANY product 
being RF quiet unless you know the guy saying so is someone like Steve 
or Jeff. Most of us are so heavily bathed in RF noise that they combine 
to overpower even something that is screaming noisy!

73, Jim K9YC

On 7/18/2022 6:25 PM, Steve Dyer via RFI wrote:
> Jeff, et al,
> This is just NOT TRUE.... These blanket statements really don't help 
> anyone looking for guidance.
> I have a variable speed compressor and variable speed fans on both the 
> outdoor unit and the air handler.
> No RFI problems whatsoever.
> My system is a Bryant Evolution Extreme system. Factory filter on the AC 
> input to the compressor unit and twisted pair control lines.
> Variable speed motors can be done right or wrong. When done right they 
> are far more efficient and quieter (audio) than any PSC motor. I don't 
> even hear air moving when it runs.
> It's a 4 ton system that replaced 5 ton of old school A/C. The variable 
> speed compressor typically runs at 60% on a hot summer day. Total 
> current draw is about 2.1 kW at that level. I keep the house nice and 
> cool and with solar don't feel any guilt about turning the 'stat down.
> Installs can be done right or wrong.
> It's not the tech. It's the implementation.
> Sounds like you have a good installer.
> 73,
> Steve
> W1SRD
> 
> 
> On 7/18/2022 16:14, David Eckhardt wrote:
>> Avoid variable speed blowers at all costs!
>>
>> Dave - WØLEV
>>
>> On Mon, Jul 18, 2022 at 9:55 PM Jeff Blaine <KeepWalking188 at ac0c.com> 
>> wrote:
>>
>>> We are looking at a replacement HVAC and these items are proposed for
>>> the install.  I'm paranoid about the RFI noise profile out of modern
>>> HVAC systems and would be interested in any comments.
>>>
>>> The Lennox P/N recommended are:
>>>
>>> Merit series - ML14XC1$-042 compressor 14 SEER
>>>
>>> Elite series - EL280UH090E488 dual-speed (2-stage?) furnace 80%
>>>
>>> The installer is aware of the Lennox 604552-01 kit which includes a
>>> differential filter and a snap-on toroid.  I've made it clear that the
>>> single snap-on toroid is likly and that a multi-turn type 31 would be
>>> used in lieu if needed.  Which would not have a warranty issue as the
>>> HVAC guy and I share a common electrician who has vouched for the safety
>>> of this "mod."  And we have discussed that similar (multi-turn toroid)
>>> treatment may be added to the thermostat line as well.
>>>
>>> Appreciate any advice on other guys who may have experience with Lennox
>>> gear in general, or these families in particular.
>>>
>>> 73/jeff/ac0c
>>> alpha-charlie-zero-charlie
>>> www.ac0c.com
>>>
>>>
>>> _______________________________________________
>>> RFI mailing list
>>> RFI at contesting.com
>>> http://lists.contesting.com/mailman/listinfo/rfi
>>>
>>
> 
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