Buderus Logamax plus GB162 Technical Manual page 64

6 System examples
Pump modulation setting for different applications
Application
One directly connected
heating circuit, differential
pressure may be selected
for the specific system
Heating circuit connected
via low loss header or
system separation with
heat exchanger
Table 25 Setting options for pump modulation via the RC35 programming unit for different applications (standard
settings on blue background)
Anti-seizing control
Independent of the operation of the internal heating circuit
pump in the Logamax plus GB162 gas condensing
boilers, the UBA3.5 starts a pump test run if the heating
circuit control unit has not issued a heat demand for 24 h.
This prevents the heating circuit pump from seizing.
Additional external heating circuit pump
Particularly with low system design temperatures, such as
40/30 °C in underfloor heating systems, the internal
heating circuit pump of the Logamax plus GB162 gas
condensing boilers may prove inadequate. In this case
allow for a circuit via a low loss header with secondary
pump ( fig. 63).
64
Recommended Type of control
setting at the
RC35
programming
unit
Δp = constant
4
Δp = constant
3
Δp = constant
2
Δp = constant
1
Output control
between
0 maximum and
minimum
modulation
Residual head for Logamax plus
GB162-15 GB162-25
GB162-25 T40S
[mbar] [mbar]
240 300
200 250
150 200
100 150
Output-dep
endent Output-dependent
fig. 52, fig. 53, page 60
page 60
6 720 645 821 (2010/09) – Logamax plus GB162
GB162-35 GB162-45
[mbar] [mbar]
300 350
250 300
200 250
150 200
Output- Output-
dependent dependent
fig. 54, fig. 55,
page 60 page 61