Application's Manual

Data subject to change without notice | 01.2011 BOSCH THERMOTECHNOLOGY CORPORATION
THERM Tankless Water Heater Applications Manual | 19
8.2.4 Bosch gas water heater with direct recirculation loop
Use a circulator, aquastat and/or timer, to keep a loop of
hot water constantly hot and ready to use. This limits
wait time for hot water delivery to the tap and excessive
waste of water. Insulate piping in hot water recirculation loop to limit
heat loss.
If the water heater is used within an approved hot water
recirculation application and supplied with circulated
water, the heat exchanger warranty is decreased. Please
refer to the installation manual for detailed warranty
period information.
Note:
Drawing is not to scale.
Cold water piping to fixtures not shown for clarity purposes.
Symbols
Pressure
relief
valve
Service
valves
Flow
direction
Bronze or
stainless steel
circulator/
pump
Aquastat
Timer
Flow
check
valve
Potable
water
expansion
tank
Cold
water
supply
Hot Cold
Domestic
hot water tap
Domestic
hot water
tap
Domestic
hot water
tap
Domestic
hot water
tap
Y-strainer
Applicable Bosch Models:
•Bosch 520 PN
•Bosch 520 HN
•Bosch 660 EF/EFO
•Bosch 830 ES
•Bosch 940 ES/ESO
•Bosch C 1050 ES
•Bosch C 1210 ES/ESC
See Chapter 5.1 for recirculation pump parameters