[RFI] Multi-Stage High Efficiency Air Conditioner Units

[Kim Elmore]

A two-stage unit probably wouldn't help much here in OK: we often see 
stretches of a month where temperatures are close to (or over) 100F with 
high humidity, usually across July and August. We easily see 
temperatures of 90 F and above late May through September. So our 
Summers can be nothing short of brutal here. We have upstairs and 
downstairs single-speed units that are getting long in the tooth, as are 
our two gas furnaces. If we run them to failure, it'll be inconvenient 
and we won't have the luxury of shopping and choosing. I'll ask the HVAC 
people to look specifically into any RFI kits offered by the 
manufacturer while also having enough type 31 ferrites on hand to 
install on whatever we get. I figure that they can go inside the outdoor 
units before they're set up, and they'll also go on the thermostats on 
the inside of the home, too.

Kim N5OP

On 2/17/2020 9:20 PM, Grant Saviers wrote:
> I have a Carrier heat pump, but it is two speed, not variable speed. 
> The HVAC engineer (who is the best I've ever met) said, "in our 
> climate it's not worth the extra complexity & cost for the small EER 
> improvement."  No RFI for me.
>
> Grant KZ1W
> Redmond, WA
>
> PS Kwh are cheap here.
>
> On 2/17/2020 19:10, Kim Elmore wrote:
>> It seems that I may have used the wrong terminology, as the latest 
>> approach to this is "variable speed compressor," where the compressor 
>> speed is varied. Looking briefly into this, I found that some 
>> companies tout that they do this with an inverter. apparently, AC 
>> input is rectified, possibly filtered, then converted to variable 
>> frequency AC, which is used to control the compressor speed. 
>> Depending on how that's done, it sounds like it could either be 
>> RFI-silent, or a catastrophic screamer.
>>
>> I have a bid on a Carrier system -- does anyone have experience with 
>> variable-speed Carrier units? Does anyone have contacts at Carrier 
>> that I could talk to about any RFI associated the units that have 
>> been specified in the bid and what measures might need to be taken?
>>
>> Kim N5OP
>>
>>
>
-- 

Kim Elmore, Ph.D. (Adj. Assoc. Prof., OU School of Meteorology, CCM, PP 
SEL/MEL/Glider, N5OP, 2nd Class Radiotelegraph, GROL)

/"A great second violinist plays second fiddle to no one." //– Robert C. 
Marsh, Chicago Sun-Times./