Dhw Circulation Line For Dhw Cylinder - Buderus Logamax plus GB162 Technical Manual

5.6

DHW circulation line for DHW cylinder

Any DHW circulation line is a heat consumer. Lines that
are long, poorly routed or inadequately insulated can lead
to substantial heat losses. Therefore, DHW lines should
be kept short if DHW circulation lines are not installed.
However, from a DHW line length of approx. eight metres,
the connection of a DHW circulation line is
recommended.
Where DHW circulation cannot be avoided, observe the
following rules:
• The DHW circulation connection can be installed in the
cold water inlet of the Logalux S120 W DHW
cylinders. In connection with the Logamax plus
GB162, the connection piece for PZ DHW circulation
pumps can be fitted to the safety assembly of the
S-Flex connection set for the sanitary side. Install the
pipework in conjunction with the Logamax plus GB162
on site ( fig. 43).
• Minimise the amount of circulating water. This requires
a pressure drop calculation for the lines or a sizing of
the pump. Temperature differentials from 5 K between
the DHW outlet and the DHW circulation inlet must be
reduced.
• The EnEV specifies that conventional time switches or
other automatic facilities for switching off the DHW
circulation pump must be provided. The RC35
programming unit within the Energy Management
System (EMS) provides its own time channel for DHW
heating. Consequently, the DHW circulation pump can
also be programmed for different operating modes.
It is generally adequate if the DHW circulation pump is
operated for approx. five minutes in the morning, midday
and in the evening.
AW EK
Logalux
S120 W
EL
Fig. 43 Version of a DHW circulation line for the
Logalux S120 W DHW cylinder
6 720 645 821 (2010/09) – Logamax plus GB162
AW
PZ EZ
KR
EK
6 720 642 463-31.1il
AW EK EZ
Logalux
S135 RW
S160 RW
EL
Fig. 44 Version of a DHW circulation line for the
Logalux S135 RW and S160 RW DHW
cylinders
AW
EZ
Logalux
SU...W
EL
Fig. 45 Version of a DHW circulation line for the
Logalux SU... W DHW cylinders
Key to fig. 43 to fig. 45:
AW DHW outlet
EK Cold water inlet to DIN 1988-2
EZ DHW circulation inlet
KR Check valve
PZ DHW circulation pump
DHW heating
AW
EK
KR PZ EZ
6 720 642 463-32.1il
EK
AW
EZ
KR
PZ
7 747 009 801-29.1il
5
51