I have been waiting 10 years!! I bought a house 10 years ago had one of these and always made a clicking noise kind of erratically thanks to this video. I just found a bent plate on one of the cells. I had no idea you could run it with only one cell to test it. This It’s just saved me a few hundred dollars! anyone I spoke to over the years had no idea what could be wrong and any other video I saw just told you to replace the cells with a regular paper filter. It’s the cheapest way to fix it!