here in AZ. This is my experience with it... My Z overheated with water temps going over 225 F. one day when the ambient was about 104 F. It turned out my fan motor polarity was swapped. I fixed that issue and ran it again on about the same amb temp day. This time my water temp came nearly about 220 F. I ended up putting the stock clutch fan back on and found my water temp barely broke 205 F.
Ash was a great guy though and kept up with my correspondences for help. In the end I returned it and he gave me a full refund.