Duct plug (2 pcs.)
If necessary, you can close the ducts in the hot tub with duct plugs. You can empty the heater (there is a plug for that in the front part of the heater) after the ducts have been closed. That way you will not have to empty the hot tub but will be able to protect the heater from freezing. Please refer to the instruction manual of the heater for extra information about the freezing risk.