Bosch GWH C 920 ES - 9 Residential Solar Applications; Tankloading

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Bosch applications manual
Bosch applications manual | 06.2009
BOSCH THERMOTECHNOLOGY CORPORATION
9 Residential Solar Applications
Introduction
This section gives a general overview of tank loading and in line
booster applications for domestic hot water in conjuction with solar
water heating. For additional system details, consult the Bosch
Solar Technical Guide.
9.1 Tank loading
9.1.1 Solar DHW system with gas tankless water heater tank
loading
In this system the gas tankless water heater keeps the comfort zone
at top of tank at desired temperature.
 Use GWH 715 ES, GWH C 800 ES, or GWH C 920 ES with
aquastat that activates circulator.
 Timer recommended to interrupt reheating during night time.
Solar
Pump
Station
Domestic
Hot
Water
Solar
Controller
Cold
Water
Supply
Symbols
Service
valve
Pressure
relief
valve
Honeywell
Am-1 series
thermostatic
mixing
valve
Solar
storage
tank
Flow
direction
Potable
water
expansion
tank
Well
thermometer
Circulator
Thermostatic valve
Setpoint 120°F
Collector
sensor
Aquastat
or tank sensor
Tank
sensor
Drain
valve
Twin
tube
Bosch GWH 715 ES,
Bosch GWH C 800 ES,
Bosch GWH C 920 ES/ESC
Expansion
tank
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.
See Chapter 5.2 for tank loading pump parameters