I had the same experience, one was perfectly fine, the other one was screaming loud, both new, pretty obvious one was defective.
They did replace that pumps wet side quickly, but that one too was defective.
I was told it's pretty much impossible to get 2 in a row that were defective, and I was also told to wait two weeks, what a miserable two week period listening to that thing scream.
Finally at two weeks I was able to send back for testing.
They told me both wet and dry were bad and giving me new of both, but they did not, just the wet side was replaced(I had a mark on my original dry side I quickly recognized)
I don't think they want to admit any parts were defective, but of course this happens sometimes, wish they would step up on customer service as I thought it was terrible for all the years I've used their products and what we pay for them.
Luckily replacing that wet side has me good now, but they sent a weird email telling me how I better measure my glass properly or my warranty would be voided, it's half inch, stated that many times, not sure why they felt the need to send that and I hope I don't have issues later and have that be a lame excuse to not back their warranty.
I'm very dissapointed w/ ecotech and how I was treated, I hope they resolve your issue.
