[scottz]

Mine was also really loud. I did three things;

1. Installed a water pump silencing kit
https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

2. Isolated the pump by putting a rubber mat under it

3. Probably the biggest help was making sure the PEX lines did not touch each other and were fastened down securely.

It is still louder than my previous unit, but tolerable.