Domestic Hot Water Recirculation With External Pump - Bosch Greentherm 9800 SEO 160 Installation And Operating Instructions Manual

6.4 Domestic hot water recirculation with
external pump
Direct recirculation through the tankless water heater is
permissible, however, the heat exchanger warranty is reduced;
see warranty at www.boschheatingandcooling.com.
The following drawings are provided to illustrate possible
recirculation designs. These schematics are for illustration only
and must not be used for actual Installation without
appropriate engineering and technical advice from a properly
licensed professional in the locality where the installation is
made.
Recirculation menus for Greentherm 9800
SE O are only available with the Bosch
remote control.
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 is available. All the features of recirculation
can be used with the Bosch remote control.
Fig. 15 Recirculation application with a dedicated return
line
[1] Cold water supply
[2] Check valve field supplied
[3] Circulator pump field supplied
[4] Expansion tank field supplied
[5] Circulator cable accessory
[6] PRV
[7] Shutoff valves field supplied
[8] Greentherm 9800 SEO / SECO
Greentherm 9800 SEO 160/199 | SECO 199
Fig. 16 Recirculation application using the cold water line
and cross-over valve
[1] Cold water supply
[2] Check valve field supplied
[3] Circulator pump field supplied
[4] Expansion tank field supplied
[5] Circulator cable accessory
[6] PRV
[7] Shutoff valves field supplied
[8] Greentherm 9800 SEO / SECO
[9] Cross-over valve, field supplied
Recirculation application showed in fig. 16 is
for Greentherm 9800 SEO/SECO.
Models with build-in pump cannot be used.
6.4.1 Recirculation options
House Recirculation
This recirculation option uses the appliance's NTC sensor along
with the optional schedule to control the pump.
Tank loading
This recirculation option gives the option of using one of three
temperature sensors to control the recirculation option. The
scheduling option is not available for tank loading, except for
commercial models.
• External NTC - 7 736 504 583
– Only compatible with Bosch cable/sensor accessory
(7736504583).
• Aquastat - 7 736 504 584
– The aquastat connector kit (7736504584) must be
used to connect a field supplied aquastat to the
appliance.
Installation instructions | 21
6 720 817 281 (2017/05)