Bosch SSB255 - Pump, Condensate Removal, and Electrical Connections

SSB 6720818454 (2016/02) US
Installation | 17
4.4.5 Pump
SSB boilers must be tted with a circulator pump. The graph in the following gure shows the pressure drop through the boiler circuit depending on the
ow rate.
SSB255
0
1
2
3
4
5
6
7
8
0510 15 20
∆ p/ Feet of Head
Flowrate / GPM
Fig. 12 SSB255 Pressure drop

It is important to ensure the pump has the correct ow rate
for the system to avoid a low water circulation situation. In
event of an inadequate ow rate, the safety devices of the
boiler will automatically stop the burner.