Cascade Operation; Control/Specification/Notes - Wolf COB Installation Instructions And Technical Manual

General
Setting the eBUS address for
cascade mode
(see installation instructions for
KM module)
DHW cylinder
Heating circuit
Low loss header
System separation
Specification
Cascade type
Rated output at 80/60 °C
Rated output at 50/30 °C
Rated heat input
Lowest output at 80/60 °C Stage 1
Lowest output at 50/30 °C Stage 1
Lowest output
32

20. Cascade operation

Control / specification / notes
These oil condensing boilers have control PCBs with functions that are optimally
matched to the digital controller type KM for cascade control. Up to four COB-29
or COB-40 oil condensing boilers (with the same output) with an output range of
18.5 kW to 112.8 kW (cascade COB-29) or 25.3 kW to 152.0 kW (cascade COB-40)
can be linked together to form a single cascade. Subject to load, this digital cascade
controller KM can control the header flow, a mixer circuit and a DHW cylinder circuit.
The digital controller type MM from the WOLF range of control accessories can be
connected to regulate an additional mixer circuit and radiator circuit. Furthermore, a
BM can be used in each case as a remote control.
For a detailed description, see also the installation instructions for the individual modules.
The eBUS address is set by pressing the reset button for at least 5 seconds after
the appliance has been switched on. After 5 seconds, the corresponding flashing
code appears (in accordance with the table) at the illuminated signal ring. Select the
corresponding eBUS address with the DHW temperature rotary selector. Your selection
of the required eBUS address is saved by releasing the reset button. No address can
be allocated more than once.
Boiler in cascade eBUS
operation address
Boiler 1
Boiler 2
Boiler 3
Boiler 4
*Factory setting (individual boiler without cascade mode)
A DHW cylinder is generally connected downstream of the system separation (e.g. via
a low loss header).
Cylinder heating is controlled via the cascade controller type KM, to which a cylinder
primary pump and the electronic cylinder sensor are connected.
To ensure the heating water flow rate through every condensing boiler is as even as
possible, the following connection types are recommended:
1. For precise hydraulic balancing, a line regulating valve can be fitted in the supply
line to every appliance.
2. Design the flow and return lines with the same length for the flow and return according
to the Tichelmann system, to ensure the pressure drop in every line is equally high.
It must not be possible for the on-site heating circuit pumps or primary pumps to influence
the function of the condensing boilers. A low loss header should therefore be installed
upstream of the heating water circuit or DHW cylinder circuit. Furthermore, ensure that
the heating water flow rate through the condensing boilers is set lower than that through
the subsequent heating circuit. The flow rate should therefore be set upstream of the low
loss header via a line regulating valve or butterfly valve.
Instead of the low loss header, a heat exchanger can be installed. If pipes are used which
are not impermeable to oxygen, this is a requirement in any case.
2 x
COB-29
kW 56.4
kW 59.2
kW 58.0
kW
kW
kW
Rotary selector,
DHW temperature
selection
1* 1*
2 2
3 3
4 4
3 x 4 x
COB-29 COB-29
84.6 112.8
88.8 118.4
87.0 116.0
18.5
19.6
19.0
Illuminated signal
ring indication
flashing red
flashing yellow
flashing yellow/red
flashing yellow/green
2 x 3 x 4 x
COB-40 COB-40 COB-40
76.0 114.0 152.0
80.0 120.0 160.0
77.6 116.4 155.2
25.3
26.8
26.0
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