The Bosch Greentherm T9800SE 160 and the Greentherm T9800SE 199 gas tankless water heaters have an optional cable accessory that enables the heater to be connected to an external pump for recirculation application. Direct recirculation through the tankless water heater is permissible, however, the heat exchanger warranty is reduced to 3 years.
This appliance has been designed to permit recirculation by controlling an external pump. For this function, the external pump must be electrically connected to the appliance - Bosch cable accessory (7736504585). External pump will be sized by contractor for the size of the application.
For further questions on the cable accessory or to place an order please call Global Protankless Supply at 866-289-4652.