Hayward SumHeat HP5171DT3 Manuel D'instructions Et D'installation page 74

4. USER INTERFACE (continued)
4.6 SILENT function settings
Silence mode enables the heat pump to be used in economic and very silent
mode when the heating needs are low (maintaining the pool temperature or
need for ultra-silent operation).
This function can be Activated/Deactivated manually or using a Timer.
Manual Activation
1
2
Silence mode activated
22