1-Boiler System With Unimat Ut-L Boiler With Condensing Heat Exchanger: Boiler Circuit Control Unit With Hydraulic Separation - Bosch UT-L 1 Technical Manual

9.10 1-boiler system with UNIMAT UT-L boiler with condensing heat exchanger: boiler circuit control
unit with hydraulic separation
Fig. 44 System example with boiler circuit control unit and hydraulic separation (list of abbreviations
1)
[ ] Enabling (potential-free)
 Burner stage I
 Burner stage II or modulation
The circuit diagram is only a schematic
illustration! Information regarding all
system examples  page 47 ff.
AREA OF APPLICATION
• UNIMAT UT-L boiler with ECO 6 condensing heat
exchanger
• CFB boiler circuit control unit
– Maintaining the operating conditions
– Enabling of burner stages
• System structure in this form if a feed pump is
required, e.g. through sizing the heating circuit
pumps, or if several distributor stations are required,
or if the distributor stations are installed far apart
Brief description of the system
• Minimum return temperature controlled via a
separate actuator in the boiler circuit and a boiler
circuit pump as primary circuit pump
• 2-stage or modulating burner mode
• Control of heating circuit using CFB control unit or on-
site control unit
UNIMAT
WH
SR
KR PK
FZ
RK VK
VWT
CFB 810
+ CME 930
RWT
HK1
HT
THV
THV
FV1
FV2
PH2
PH1
SH1 SH2
Function description
The 3-way valve is actuated to control the return
temperature. The return temperature sensor measures
the boiler return temperature. If this falls below the set
value, the flow rate to the heating return is constantly
restricted by actuating the 3-way valve.
If the return temperature rises above the set value, the
3-way valve is reopened and the flow rate to the heating
circuit increases. Targeted utilisation of the condensing
effect is possible with the condensing heat exchanger
(ECO 6) connected separately to the low temperature
heating circuit.
Special design information
• If shut-off valves are installed between the boiler and
ECO 6, an additional safety valve and pressure gauge
are required at the ECO 6.
• Allow for a low loss header.
• Switch the boiler circuit pump to constant mode or
set a run-on time of 60 minutes.
• The ECO 6 pump must be actuated in parallel to the
burner. Match the head to the pressure loss of the
ECO 6 and the connection pipework.
• Protect the ECO 6 with an on-site safety temperature
limiter or high limit safety cut-out.
System examples | 63
HK2
NT
PWT
KR
6 720 803 977-24.1itl

page 47)
6 720 807 794 (2013/04)