Use
Caleffi TankMixer™ 520 series thermostatic mixing valves are designed to be installed at
the hot water heater. The 520 series valve cannot be used for tempering water temperature at fixtures
as a point-of-use valve. They are not designed to provide scald protection or chill protection service.
They should not be used where ASSE 1070 devices are required. Wherever a scald protection
feature is required, Caleffi 5213 series high performance mixing valves need to be installed. For safety
reasons, it is advisable to limit the maximum mixed water temperature to 120°F when anti-scald
devices are not used at each fixture.
Construction details
Thermal shut-off
In the event of accidental cold water supply failure, the shutter seals off the hot water passage,
thus preventing the delivery of mixed temperature water. This is only guaranteed when there
is a minimum temperature difference between the inlet hot water and the mixed temperature
water delivery of 27°F.
Water heater
As a result of the NAECA, many water heaters now have more insulation making them
physically larger, for the same water capacity, than the older models. So units with less
capacity are installed requiring higher temperature settings to provide the capacity users were
previously accustomed, requiring mixing valves to temper the water to safe levels.
Caleffi TankMixer™ 520_AX series thermostatic mixing valves with cold water tee assembly
and flexible connector will conveniently fit a typical gas-fired water heater and a wide variety
of other water heaters. A recirculation return can be connected at the side port of the cold
water tee.
