The main function of Domestic Hot Water re-circulation in plumbing systems is to control that there is no unnecessary waste of the domestic water consumed, plus it keeps the water temperature constant along the line.
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It is also possible to refine the re-circulation control by adding a water temperature probe to the re-circulation pipe so that the circulation starts at the times indicated by the timetable, but only if the probe temperature is below a certain value (for example, 38°C):
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You then Then you proceed by associating a probe to the circulation zone as in the previous image and set the set point on the Zone Parameters page:PHOTO TBD
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Setting 38°C means that only below 38°C (and at the times when the timetable is turned on) the zone will be active and turn on the re-circulation water pump, which must be associated with the output of the zone itself, in the example shown is the zone 1:PHOTO TBD
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Output 50 must not be used in this case.
Finally, the circulation will be switched off either you are outside the set times, and also when the probe temperature exceeds the set point (38°C) plus the hysteresis set in the DHW page:PHOTO TBD
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In the example shown the hysteresis is 5 3 K, therefore the circulation could switch off even when the probe detects a temperature higher than 43°C41°C.