Hi there.  This forum doesn't seem very active lately, I'll be surprised to even get one response.  I just got a Kenmore Iridium, and while I love it I am concerned about its performance.  When I push the power nozzle forward on the carpet (mind you I have very flat carpet in my apartment, and I've tried on all height settings) it sounds fine, but when I draw it back the motor changes pitch.  Almost like it is straining.  My Elux Diamond Jubilee has always done this but it's an antique.  My Hoover Celebrity (before the p/n shattered all to pieces), Rainbows, and Filter Queen never do this.  When I sold for Sears, the Panasonic made Kenmores never did it either.  I don't have any experience with LG vacuums except for this one so I want to know if it is normal behavior for this machine and power nozzles in general.  If you have an Iridium, does the power nozzle make a different sound on the back stroke?  I have TERRIBLE luck with power nozzles... my Hoover Celebrity base broke last month (the part that holds the brushroll!), and my antique Whirlpool made Kenmore canister's neck/elbow broke all to pieces as well.   What next?  Think I should stick to uprights.  Thanks!

Hi VF,
 
My Iridium's power nozzle is still doing a fine all around job.  If you have low pile carpeting the best is to set it at "L" -- never "X-L" and drop the motor speed to medium especially if you have a dense, low cut weave like Axminister.  (Vacuuming with medium motor speed is no sin when going over frequently vacuumed carpeting.)  
 
Though I have had no real problem with "bucking" as I'm tall and usually leave the telescopic wand all the way out to the last detent, the nozzle does have a tendency to dip slightly when pulled backward meaning a seal of the nozzle mouth against dense low pile might cause the nozzle's motor labor a little.
 
Test this by grasping the hose handle loosely and taking note whether or not the power nozzle pulls forward on its own.
 
I would also note that the Iridium's power nozzle has very, very firm tufts on its brush roll.  That along with the development of a seal on the backpass might be added reason for a change in sound.  
 
I think if anything serious was going on the nozzle would quite likely shut off the same as mine has done when used on very deep pile.
 
Venson

When I tried an Iridium I found its power brush slowed down when I was pulling the wand backwards.  Apparently the brushhead "droops" when being pulled backward and puts extra load on the  motor.
 
This was some time ago...the nozzle may be redesigned by  now.

There of course will be no changes in design as the Iridium has been discontinued.  I would note however that the power nozzle for the LG machine that the Kenmore Iridium was cloned from was strikingly different, at least in apppearance, from the one that was outsourced for the Kenmore version.  The nozzle we use with our Iridiums is quite similar to the one Riccar and Simpicity uses.
 
Venson