Product Overview

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Kills bacteria instantly
Kills 90% of bacteria in 2 minutes
Kills 90% of bacteria in 2 hours
Optimum temperature
for growth of bacteria
Surviving bacteria inactive
Construction details
Anti-scale materials
The material used in the construction of the Caleffi TankMixer™ 520
series thermostatic mixing valve reduces jamming caused by lime
deposits. All the working parts such as shutter, seats and slide guides
are made of a special anti-scale polymer material, with a low friction
coefficient, assuring long term performance.
Temperature setting and locking
The control knob permits temperature setting between minimum and
maximum in one turn (360°). It also has a tamper-proof system to lock
the temperature at the set value.
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. Additionally, the tight closing hot
inlet port prevents temperature creep in recirculation applications.
Check valve
In systems with thermostatic mixing valves, check valves must be
installed to prevent undesired backflow. The TankMixer™ 520_AX series
mixing valves are supplied complete with a check valve (A) on the cold
water cross outlet port to the mixing valve.
Operating principle
The thermostatic mixing valve mixes the hot and cold water at the inlets
to maintain constant mixed water at the desired set temperature. The
TankMixer™ 520 series point of distribution mixing valve is an angled
configuration combined with a flexible hose and cold water cross
for easy installation to most water heaters for direct mounting to the
universal ¾” male NPT threaded top pipe connections with a variety
of outlet connection styles. This provides increased usable hot water
capacity on existing or new high efficiency water heaters by allowing
water to be stored at a higher temperature and safely delivered at lower
adjustable temperatures to all fixtures. In addition, it can be used to
reduce legionella growth by allowing the water heater thermostat to
be set at 140°F. The flexible hose length allows mounting to all water
heater tank sizes. The TankMixer™ 520_AX series comes standard with
a recirculation port that can be plugged or used for connecting to a hot
water recirculation loop.
Thermal disinfection
The diagram shows the behavior of the bacteria Legionella Pneumophila
when the temperature conditions of the water in which it is containedvary.
In order to ensure proper thermal “disinfection”, the values must not be
below 140°F.
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120
130
140
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0.11 10 100 1.000 10.000
Seconds
Partial burning
Total burning
Safety condition.
Maximum exposure time
at a given temperature
Temperature — exposure time
Legionella-scalding risk
In systems producing domestic hot water with storage, in order to
avoid the dangerous infection known as Legionella, the hot water must
be stored at a temperature of at least 140°F. At this temperature it is
certain that the growth of the bacteria causing this infection will be
totally eliminated. At this temperature, however, the water cannot be
used directly.
As shown on the diagram opposite, temperatures of more than 120°F
can cause burning very quickly. For example, at 130°F partial burning
will occurr in approximately 30 seconds, while at 140°F partial burning
will occurr in approximately 5 seconds. The time may be reduced by 50
percent or more for children and elderly people.
In view of the above, it is necessary to install a thermostatic mixing valve
which can:
- reduce the temperature at the point of use to a value lower than that
of storage and suitable for sanitary users. For safety reasons, it is
advisable to limit the mixed water temperature to 120°F when point-
of-use anti-scalding thermostatic mixing valves are not present at all
fixtures.
- maintain the temperature constant when the incoming pressure and
temperature conditions vary.
A