the mix valve is used to fill 2 turtle tanks in the house. the valve is off the H/C that feeds the washer. wondering if I should have a check on both lines, if it turns out the 5000 doesn't. there is currently 1 on the Cold.
spoke with Taco. 5000 that is 15 years old did not have check valves built in. And the sign of a great plumber who did the install, just put a check valve on cold when Taco tech advised both hot and cold. Oh well.