Open Loop Space Heating; External Storage Tank - Bosch GWH 345 ESR Applications Manual

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4 Open Loop Space Heating

Introduction
This section is designed to provide techniques for using a recirculat-
ing tankless water heater to heat domestic water and provide space
heating in residential applications. As with all installations, check
with the local authority having jurisdiction. Some jurisdictions may
not allow these types of applications.
P2
Potable water
expansion tank
Bronze circulator
sized according to
UPC standards
Note: Piping to fixtures not shown for clarity purposes.
Note: This drawing is conceptual in nature and does not address all design, installation or safety considerations.
Additional safety and/or auxiliary equipment may be needed. This diagram is for reference use by officials, designers and licensed installers.
It is expected that installers have adequate knowledge of accepted industry practices for the equipment, procedures, and applications involved.
Drawing is not to scale.
Application manual | 02.2009
Cold water
feed
P1
Symbols
Pressure
relief
valve
Thermostatic Thermostatic
mixing mixing
valve valve
GWH 345/450 ESR applications manual

4.1 External storage tank

The appliances shown in this section are approved under ANSI
Z21.10.3 and CSA 4.3 as circulating gas water heaters. Only open
loop applications are approved under this standard.
4.1.1 Radiant space heating and DHW plumbing diagram
Bosch GWH 345 ESR,
Bosch GWH 450 ESR
DHW
Radiant
Flow
piping
direction
12K ohm
Service
thermistor
valves
with immersion
well
BOSCH THERMOTECHNOLOGY CORPORATION
PS
Storage
tank
Air
separator
Drawing # ROL CN revA 10/07