Application's Manual

Data subject to change without notice | 01.2011
BOSCH THERMOTECHNOLOGY CORPORATION
THERM Tankless Water Heater Applications Manual
30
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12.2 Basic tank loading with domestic recirculation
The following application outlines general tank loading with one or
more gas tankless water heaters in parallel. Domestic hot water
recirculation shown is optional.
System parameters:
• Aquastat/tank sensor Tset 120-140°F, <10°F differential.
• 30-119 gallon storage tank recommended
• DHW return line can tie directly into tank if fi ttings are available.
• Individual pumps (i.e. UP26-99) can be used on supply to each
heater or one pump (as shown) for the entire system
See Chapter 5.1 and 5.2 for pump parameters
Symbols
Service
valve
Pressure
relief
valve
Solar
storage
tank
Flow
direction
Well
thermometer
Bronze or
stainless
steel
circulator
Potable
water
expansion
tank
Flow
check
valve
Domestic
Hot Water
supply
Cold
Water
Supply
Aquastat
or tank sensor
DHW
recirculation
pump
Hot water
recirculation
return line
Drain
valve
Applicable Bosch Models:
•Bosch 830 ES •Bosch 940 ES
•Bosch C 1050 ES •Bosch C 1210 ES/ESC
Aquastat / Water Heater setpoints
Model Number Aquastat setpoint Water heater
setpoint
C 1210 ESC ≤140°F 14°F above Aqua-
stat setpoint
830 ES,
940 ES,
C 1050 ES,
C 1210 ES
≤126°F* 140°F
* If local codes require higher setpoint or to increase the recovery
capacity of the water heater, contact Bosch Thermotechnology.