Bosch GWH C 920 ES - Basic Tank Loading with Domestic Recirculation

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Bosch applications manual
Bosch applications manual | 06.2009
BOSCH THERMOTECHNOLOGY CORPORATION
11.2 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
Domestic
Hot Water
supply
Cold
Water
Supply
Aquastat
or tank sensor
DHW
recirculation
pump
Bosch GWH 715 ES, Bosch GWH C 800 ES, Bosch GWH C 920 ES/ESC
Hot water
recirculation
return line
Service
valve
Pressure
relief
valve
Solar
storage
tank
Flow
direction
Well
thermometer
Bronze or
stainless
steel
circulator
Potable
water
expansion
tank
Flow
check
valve
Drain
valve
Aquastat / Water Heater setpoints
Model Number Aquastat setpoint Water heater
setpoint
GWH C 920 ESC ≤140°F 14°F above
Aquastat setpoint
GWH C 920 ES ≤126°F* 140°F
GWH 715 ES ≤126°F* 140°F
GWH C 800 ES ≤126°F* 140°F
* If local codes require higher setpoint or to increase the recovery
capacity of the water heater, contact Bosch Thermotechnology.