I had the same problem.
We could put one cell in and it worked with out clicking. Putting the second one in solo however, it was clicking.
I looked closely at the second cell and discovered that two of the vanes on the side with the wires were bent at about 20 degrees off. Adjusting this and reinserting reduced the clicking but not completely. I pulled the cell and focused on the same two vanes and discover one was also bent in, gently pulled it back and no more clicking!
My wife had cleaned the filters and my 6 yr old and 4 year old had to help. I wonder how they got bent?!
We have had the cleaner for about 6 yrs and no problems until this last cleaning.
Be very careful in adjusting the cells. Aluminum does not like being bent and weakens each time it is moved, like pulling a tab off a beer can (of course the cells are made from much thicker and higher grade aluminum)!
Even after making sure the fins were spaced apart, I still had clicking from the same damaged fin. I noticed it had some buildup on the fin from where it was arcing. I put a small piece or duct tape on the bad spot and it seems to have fixed it. I am going to monitor the cleaner all day to make sure it is functioning properly.
Cliking noise on power up will come from 1 place: vents! check all blades, if there is a wire hanging there check if the blades dont touch thier surroundings if so make a space...(by all means) keep in mind there are more then 1 vent inside good luck windman
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