4.13 Space Heating Applications - Bosch 940 ES Installation And Operating Instructions Manual

Installation instructions

4.13 Space heating applications

CAUTION:
▶ If the set point temperature is above 120°F, precautions
should be taken to protect users of potable water from
scalding.
CAUTION:
▶ Propylene glycol may be used for freeze prevention ONLY
on the space heating side of the heat exchanger. Do not use
ethylene glycol (automotive antifreeze).
CAUTION:
▶ The use of a flow switch is recommended to ensure DHW
priority and to prevent "cold-blow" situations when the
Bosch tankless water heater is used with an air-handling
system. The flow switch should be used to disable the
blower on the air-handling system when domestic water is
used.
CAUTION:
▶ Ensure the primary pump is properly sized to provide
adequate flow for the system heat load. Ensure the primary
pump is properly sized to provide adequate flow for the
system heat load.
For Pump sizing please refer to the pressure drop curves,
fig. 36. Also remember to account for system piping pressure
loss. A minimum of 1.7 GPM is recommended to provide
adequate flow through the water heater when determining the
size of the primary pump.
Bosch tankless water heaters are approved for use in
combination DHW and space heating applications (open-loop
setup). These water heaters are not approved for use in space
heating only applications (closed-loop setup). Bosch supports
applications of combination DHW and space heating in an open
loop configuration if plumbed similar to FIG. 37. Use of a Bosch
tankless water heater in a combination DHW and space heating
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application will result in the product warranty being reduced to
3 years.
940 ES – 6 720 644 930 (2019/09)