Bosch C1210ESC - 5 Pump Sizing for Circulation; Pressure Drop Curves

Applications Manual THERM/GREENTHERM Tankless Water Heaters | 7
Bosch Thermotechnology Corp.
Data subject to change
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.
f Pump must be bronze or stainless steel and designed
for potable water systems.
f Size the pump according to the pressure drop curve of
your Therm model (fig. 1 below) and the loop pressure
drop tables.
f Maximum flow allowed for tank loading through the
pump loop is 5 GPM.
f Maximum flow recommended for direct DHW
recirculation is 3 GPM.
f Maximum flow allowed for mini-tank DHW recirculation
is 2 GPM.
5.1 Pressure drop curves
F
0
10
20
30
40
50
60
70
0.50.40.30.20.10.0
Flow (GPM)
Pressure (Feet of Head)
C 950 ES
C 1050 ES
C 1210 series
830 ES,
940 ES / ESO
igure 1 Pressure drop curves
For direct DHW recirculation and tank loading
applications:
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.