Bosch GWH C 920 ES - Booster Applications

Bosch applications manual | 06.2009BOSCH THERMOTECHNOLOGY CORPORATION
Bosch applications manual
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9.2 Booster applications
9.2.1 Solar DHW system with gas tankless water heater booster
The tankless water heater only runs when solar water needs a boost.
The Ariston mini tank provides small amounts of DHW instantly and
increases comfort by buffering DHW temperature. Recommended
appliances: Bosch GWH 715 ES, GWH C 800 ES, GWH C 920 ES/ESC
 Thermostatic valve 1 ensures that warm solar water bypasses the
water heater and directs cooler water through the appliance
when reheating is needed.
 Thermostatic valve 2 acts as a tempering valve that brings
potentially hot water temperatures down to a level that is safe for
the inhabitants.
Water
supply
Hot
Cold
Solar
Pump
Station
Domestic
hot water
Thermostatic
valve 1
Thermostatic
valve 2
Ariston GL8ti
mini tank
Symbols
Solar
Controller
Collector
sensor
Tank
sensor
Bosch GWH 715 ES,
Bosch GWH C 800 ES,
Service
valve
Pressure
relief
valve
Honeywell
Am-1 series
thermostatic
mixing
valve
Solar
storage
tank
Flow
direction
Expansion
tank
Well
thermometer
Circulator
Drain
valve
System parameters:
 Honeywell AM101 Thermostatic Valves required for proper
operation;
 Remove check valves from Thermostatic Valve 1 as it is used as a
diverter valve;
 Thermostatic Valve 2 is a tempering valve;
 Recommended setpoint 120°F for both Valves;
 Set tankless water heater temperature to
140° F
 Ariston mini tank will provide increased
temperature stability and quicker hot water
delivery. (recommended but not required)