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.
