5 Pump sizing for circulation
The following section outlines pump sizing for domestic
hot water recirculation and tank loading. Only models
approved for such applications are listed in this section.
Pump must be bronze or stainless steel and designed
for potable water systems.
Size the pump according to the pressure drop curve of
your Therm model (fig. 1 below) and the loop pressure
Maximum flow allowed for tank loading through the
pump loop is 5 GPM.
Maximum flow recommended for direct DHW
recirculation is 3 GPM.
Maximum flow allowed for mini-tank DHW recirculation
is 2 GPM.
5.1 Pressure drop curves
igure 1 Pressure drop curves
Bosch Thermotechnology Corp.
C 950 ES
C 1050 ES
THERM/GREENTHERM Tankless Water Heaters | 7
For direct DHW recirculation and tank loading
Run the system for 30 minutes to remove debris
from the plumbing. Then remove the unit's inlet
water lter to decrease pressure drop through
the system. If the inlet water lter, when remo-
ved, contains debris, it is recommended to install
a 40 mesh Y-strainer (installer supplied) on the
cold water inlet.
C 1210 series
940 ES / ESO
Data subject to change