Blog: Mixing Valves, Thermostatic

We get a lot of tech support calls asking about proper piping of a point-of-distribution master mixing valve when a domestic hot water system has a recirculation pump. Unfortunately, there are a LOT of incorrectly piped systems out there, resulting in either temperature creep or temperature droop in the recirculation piping...

Caleffi offers a wide selection of models with and without check valves for your convenience to compliment the 521 Series Thermostatic Mixing Valve family. Models with checks have a "...C" suffix, for example...

For a simple domestic hot water application, with a point-of-distribution mixing valve (ASSE 1017 certified) such as the Caleffi 521 Series mounted near the water heater, check valves are typically not needed unless required by local code or the local authority. That...

Best practice is to pump away from the mixing valve, not into it. Connect the suction side of the pump to the mixed outlet port of the valve. This will assure proper flow direction and balanced pressures at the hot and cold inlet ports, and will promote constant system flow and good hot/cold mixing around the thermostatic element. We sometimes...