Heatpump Inverter Driven Compressor- Any RFI Experinces?

[Carl WA1KPD]

We are going to make some changes in the heating and cooling systems here. Has anyone had experience with the Mitsubishi MXZ-3C24NAHZ is a slim and compact unit housing inverter-driven compressor running to Mitsubishi MSZ-GLO6NA air handler.


Does anybody have experiences with these and RFI?
Thanks
Carl

[WD5JKO]

Carl,

   I have a Lennox AC system with the new VFD technology. When that thing is on, on 20m, I see an S9 spurr every 20Khz on my SDR receiver. It also wipes out the AM broadcast in my home when using a ferrite loop antenna. Over 1.5 years since installation, the inverter has crapped out 3 times. Warranty coverage was contingent on getting a new 220v service, and a TPMOV transient suppressor that they recommend. Inverter blew again after that. I insisted they replace the entire outdoor unit this time. So far so good, but summer is about over.

   This new technology is finicky. An inverter crap out outside of warranty will cost you a bundle. The TPMOV suppressor used has a relay to turn off the thermostat command for 3 minutes after a line dropout, or brownout. This could be a good thing to have.

Jim
Wd5JKO

[WD4DMZ]

In my home I have two Trane heat pumps with the inverter drive. No electrical noise at all and no issue with inverter failures in the 9+ years I have had them. They are a great improvement over the old Trane units with just AC motors and on/off contactors. They are premium units and came with a 12 year parts warranty.  So far so good.

The only part that failed after the 12 month parts and labor warranty ended back in 2010 was the fan motor in the condenser unit outside. That was about a year ago. A++++ for Trane and the installer.

Rich

[W3GMS]

We are going to make some changes in the heating and cooling systems here. Has anyone had experience with the Mitsubishi MXZ-3C24NAHZ is a slim and compact unit housing inverter-driven compressor running to Mitsubishi MSZ-GLO6NA air handler.


Does anybody have experiences with these and RFI?
Thanks
Carl

Carl,

They call these mini-slit systems.  We had one installed for the museum this past Spring and I cannot detect any noise whatsoever.  Our outdoor unit can support two indoor wall mounted units.  They have various outside units to support more or less indoor units.  The reason I got a two port unit was so it can support room 3 and 4 of the museum.  Mitsubishi is a great company and have been in this business from its infancy. 

Joe     

[Carl WA1KPD]

Thanks all,
Glad to hear of your experience Joe. Yes, we are splitting the system so we have 3 units in bedrooms upstairs, and one unit in the family room/kitchen area.
Currently, we have radiant floor heat in the entire 1st floor, and a very unusual 2nd floor which originally had hot air, but someone installed heating coils in the ductwork and provided convection as the medium for heat. Very "ahem" unique.
Decided to upgrade a2nd floor and the opinion of most installers was the heat pump made the most sense as we would also have AC on those few days or week we need it.
It is amazing, I have done enough research to determine it can handle the climate on its own. One trick they get around the bitter cold is to oversize the unit so you get the heat on those few really cold periods, although at low efficiency.
Carl 

[n1ps]

Inverters used for powering compressors etc  for new high efficiency heating/HVAC systems are going to be more common.  The mini states are just one of many including geothermal and the latest....thermodynamic solar panels.  So prepare for more trash and hash.  Keep a good supply of ferrites on hand....

Remember when we were horrified when the first switch mode power supplies came out in the 70s?  At least in those days Part 15 meant something....

~ps