Wolf FGB-K Series Installation And Maintenance Instructions For Contractors page 30

Operating modes
(operating mode button)
Operating mode button (5)
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15. Control unit
Operating mode button (5) is used to select the boiler operating mode.
"Standby (OFF)", "Summer mode" or "Winter mode"
If the appliance is connected to a BM-2 the operating mode button is
disabled. The BM-2 takes over this function.
Standby (OFF)
The boiler is switched off, only frost protection is enabled.
Winter mode
Winter mode, heating operation and DHW heating are enabled.
Summer mode
Summer mode, only DHW heating is enabled.
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