Troubleshooting
Under normal operating conditions the Caleffi 521 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.
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