CALEFFI TankMixer 520 Series User manual

Function
The Caleffi TankMixer™520_AX series kit combines a three-way
thermostatic mixing valve with a cold water tee and flexible pipe for
easy installation directly on a typical gas-fired water heater and other
water heaters that now comply with the National Appliance Energy
Conservation Act (NAECA). The TankMixer™maintains the desired
output temperature of the mixed water supplied at a constant set
value compensating for both temperature and pressure fluctuations
of the incoming hot and cold water. The mixing valve also features a
thermal shut-off function that operates in the event of a cold water
supply failure at the inlet. Also available as body only, for a wide
variety of separately-sourced end connections, the angle style body
design offers improved fluid dynamics for better performance and
reduces installation labor and materials, eliminating a piping elbow
in typical installations.
The valve has been specifically certified to ASSE 1017 and Low
Lead Plumbing Law by ICC-ES.
TankMixer™ water heater tank mixing valve
520 Series
© Copyright 2017 Caleffi
NA10482
www.caleffi.com
Product range
52050_AX series kit: Adjustable three-way thermostatic mixing valve, angle body with cold water
tee and flexible connector, connections ¾” NPT female to water heater; ¾” sweat,
press, and NPT male union mix outlet/cold water inlet.
52051_AX series kit: 52050_AX series kit with mixed outlet temperature gauge.
520051A: Adjustable three-way thermostatic mixing valve, angle style body only for field installed
connection fittings, source separately, connections 1” male union.
Technical specication
Materials
-Valve and cold water tee bodies:
DZR low-lead brass
-Shutter, seats and slide guides:
PSU
-Springs: stainless steel
-Seals: EPDM
-Adjustment knob: ABS
-Flexible pipe: stainless steel
-Recirc. port plug: low-lead brass
Performance
Suitable fluids: water
Setting range: 5–150° F (35–65° C)
Tolerance: ±3° F (±2° C)
Max. working pressure (static): 145 psi (10 bar)
Max. working pressure (dynamic): 75 psi (5 bar)
Max. hot water inlet temperature: 195°F(90°C)
Max. inlet pressure ratio (H/C or C/H) for
optimal performance: 2:1
Min. temperature difference between hot
water inlet and mixed water outlet for optimal
performance: 27°F(15°C)
Min. flow to ensure optimal performance:
0.5 gpm (2 L/min)
Certifications:
1. ASSE 1017/CSA B125.3, certified by ICC-ES,
file PMG-1357.
2. NSF/ANSI 372-2011, Drinking Water System
Components-Lead Content Reduction of Lead in
Drinking Water Act, California Health and Safety
Code 116875 S.3874, Reduction of Lead in Drinking
Water Act, certified by ICC-ES, file PMG-1360.

Leave this manual for the user.
CAUTION: If the thermostatic mixing valve is not installed, commissioned
and maintained properly, according to the instructions contained in this
manual, it may not operate correctly and may endanger the user.
CAUTION: Make sure that all the connecting pipework is water tight.
CAUTION: When making the water connections, make sure that the pipework
connecting the TankMixer™thermostatic mixing valve is not mechanically
overstressed. Over time this could cause breakages, with consequent water
losses which, in turn, could cause harm to property and/or people.
CAUTION: Water temperatures higher than 100ºF (38ºC) can be
dangerous. During the installation, commissioning and maintenance of the
TankMixer™thermostatic mixing valve, take the necessary precautions to
ensure that such temperatures do not endanger people.
CAUTION: In the case of highly aggresive water, arrangements must
be made to treat the water before it enters the thermostatic mixing valve,
in accordance with current legislation. Otherwise the thermostatic mixing
valve may be damaged and will not operate correctly.
SAFETY INSTRUCTION
CAUTION: All work must be preformed by qualied personnel trained
in the proper application, installation, and maintenance of systems in
accordance with all applicable codes and ordinances.
This safety alert symbol will be used in this manual to draw attention to safety related
instructions. When used, the safety symbol means ATTENTION! BECOME ALERT! YOUR
SAFETY IS INVOLVED! FAILURE TO FOLLOW THESE INSTRUCTIONS MAY RESULT
IN A SAFETY HAZARD.

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 tee 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.
5
Flow curve
Kv = 1.7
0.1
10
0.023
0.23
0.046
0.069
0.02 0.05 0.2 0.5
0.115
2.3
0.46
0.69
1.15
20 50
∆p
(ft of head)
G (l/min) (
gpm
)
23
4.6
6.9
11.5
46
0.01
0.1
0.02
0.03
0.05
1
0.2
0.3
0.5
(psi) (bar)
10
2
3
5
20
1 0.1
0.2
0.5 0.05 10
2 5 20
0.001
0.01
0.002
0.003
0.005
0.1
0.02
0.03
0.05
1.0
0.2
0.3
0.5
Cv = 2.0
9.2
0.092
0.92
0.04
0.4
4
0.004
0.04
0.4
50
115
161
50
70
2.0
5.0
190
70
100 140

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.

Installation
Before installing a Caleffi TankMixer™520 series three-way thermostatic mixing valve,
the system must be inspected to ensure that its operating conditions are within the range of the
mixing valve, checking, for example, the supply temperature, supply pressure, etc.
Systems where the 520 series thermostatic mixing valve will be installed must be drained and
cleaned out to remove any dirt or debris which may have accumulated during installation.
The installation of appropriately sized filters at the inlet from the main water supply is always
advisable.
Caleffi TankMixer™520 series thermostatic mixing valves must be installed by qualified
personnel in accordance with the diagrams in this brochure, taking into account all current
applicable standards.
Caleffi TankMixer™520 series thermostatic mixing valves can be installed in any position,
either vertical or horizontal, or upside down.
The following are shown on the thermostatic mixing valve body:
- Hot water inlet, color red and marked “HOT”.
- Cold water inlet, color blue and marked “COLD”.
- Mixed water outlet, marked “MIX”.
Locking the setting
Position the handle to the number required with
respect to the index point. Unscrew the head screw,
pull off the handle and reposition it so that the handle
fits into the internal slot of the knob. Tighten the
headscrew.
Check valve
In systems with thermostatic mixing valves, check valves should be installed to prevent
undesired backflow. The TankMixer™ 520_AX series mixing valves are supplied complete
with a check valve on the cold water tee outlet port to the mixing valve. As a convenience for
easier installations, the TankMixer™ 520051A body only can be field-installed with separately
purchased union tailpieces for ½”, ¾” or 1” npt female or male, press, PEX barb or sweat with
or without check valves (for the hot and cold inlet ports).
M
I
N
M
A
X
7
1
2
3
Index Point

Pos. Min. 1 2 3 4 5 6 7 Max.
T (°F) 95 105 115 120 125 132 140 145 150
T (°C) 35 40 45 48 52 56 60 63 65
with: T
HOT = 158°F (70°C), with: T cold = 59°F (15°C), P = 43 psi (3 bar)
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. The
temperature is set to the required value by means of the knob with the graduated scale, on
the top of the valve.
Commissioning
The Caleffi TankMixer™520 series thermostatic mixing valve must be commissioned in
accordance with current standards by qualified personnel using temperature measuring
equipment. Caleffi 520510AX, 520516AX and 5210519AX with integral outlet port temperature
gauge provide a time-saving temperature setting process to get close to the desired
temperature. Use of a digital thermometer is recommended for confirming the final setting of
the mixed water temperature. Note: For models purchased without the outlet temperature
gauge, the temperature gauge adapter with temperature gauge can be separately purchased
and field installed, code NA10056 for 3/4" models.
After installation, the valve must be tested and commisioned in accordance with instructions
given below, taking into account current applicable standards.
1) Ensure that the system is clean and free from dirt or debris before commissioning the
thermostatic mixer.
2) It is recommended that the temperature is set using a suitable calibrated digital thermometer.
The valve must be commissioned by measuring the temperature of the mixed water emerging
at the point of use.
3) The maximum outlet temperature from the valve must be set accounting for fluctuations due
to simultaneous use. It is essential for these conditions to be stabilized before commissioning.
4) Adjust the temperature using the adjusting knob on the valve. For safety reasons. it is
advisable to limit the maximum mixed water temperature to 120ºF in domestic hot water
systems.
5) The temperature may be adjusted using the control knob.
a) Adjust the temperature of the mixed water to the desired value.
b) Measure and record the temperature at the cold and hot water inlets.
c) Measure and record the temperature of the water delivered from the tap at the lowest
and highest flow rates.
d) Run a test of the thermal shut-off function. Close the cold water inlet shut-off valve and
check the mixed water delivery. The delivery flow rate should quickly drop to zero.
e) Measure and record the maximum mixed water temperature. The temperature may not
exceed the values permitted in any applicable legislation or code of practice.
f) Restore the cold water inlet supply and measure the water delivery temperature after it
has stabilized. The final temperature measured in this test may not exceed the permitted
values by ±3°F (±2°C).
In case of change to temperature setting, repeat tests in accordance with points d, e, f.
All the above information should be recorded in the commissioning report and updated in the
maintenance report whenever the valve is worked on.

Application diagrams
MAIN WATER SUPPLY
SYSTEM WITH RECIRCULATION
HOT WATER
STORAGE
MAIN WATER SUPPLY
SYSTEM WITHOUT RECIRCULATION
HOT WATER
STORAGE
T
Ball valve
Ball valve with
check valve
Temperature gauge
Pump
Expansion vessel
Thermostat
Temperature/pressure
safety relief valve
Safety relief valve
Pressure reducing
valve
Y-strainer
T
MAIN WATER SUPPLY
MAIN WATER SUPPLY
MAIN WATER SUPPLY

Caleffi North America, Inc.
3883 West Milwaukee Road
Milwaukee, WI 53208
T: 414.238.2360 F: 414.238.2366
4-21-17
Troubleshooting
Under normal operating conditions the Caleffi TankMixer™520 series thermostatic mixing
valve will provide a very high level of performance. However, in some circumstances, where the
following maintenance schedule is not followed problems may arise.
Recommended maintenance schedule:
Tests should be conducted regularly to monitor the thermostatic mixing valve performance,
as deterioration of performance could indicate that the valve and/or the system require
maintenance. If, during these tests, the temperature of the mixed water has changed
significantly in comparison with the previous test, the details given in the installation and
commissioning sections should be checked and maintenance conducted.
The following should be checked regularly to ensure that the optimum performance levels of
the valve are maintained. Check every 12 months at least, or more often if necessary.
1) Check and clean the system filters.
2) Check that any check valves positioned upstream of the Caleffi thermostatic mixing valve are
operating correctly, without problems caused by impuritites.
3) Limescale can be removed from internal components of the thermostatic mixing valve by
immersion in a suitable de-scaling fluid.
4) When the components which can be maintained have been checked, commission the valve.
Symptoms Cause Corrective action
Hot water at the cold taps a) Operation of check valve is
hindered; Check valve is not
sealing correctly.
b) Check valves not fitted.
- Replace faulty check valve
Fluctuating mixed water
temperature
a) Erratic supply temperatures at
the inlet of the valve.
b) Starvation of the water
supplies at the inlets of the valve.
c) Incorrect commissioning of the
valve.
- Restore inlet conditions within
the limits of the valve.
Erratic flow of water from
the valve
a) Insufficient water supplies
b) Fluctuations in the supply
pressures/temperatures.
c) Adverse effect created by other
draw off points on the system
- Stabilize inlet supply condi-
tions.
No flow of water from the
valve
a) In-line filers blocked.
b) Insufficient supply pressures.
c) Debris obstructing valve
operation.
- Clean filters
- Resore inlet supplies
- Clean debris or scale from
the valve.
Valve shut-off function not
performed when tested
a) Installation not compliant with
instructions.
b) Minimum temperature differ-
ence not reached.
c) Valve mechanism blocked
by dirt.
- Follow installation instructions.
- Increase hot water
temperature.
- Remove dirt/limescale from
the valve.