Product Details; Important Information On Use; Function Description / Control Strategies; Serial Standard Cascade - Bosch EMS 2 Notice D'installation

12 | Product details

▶ Before carrying out electrical work:
– Isolate all poles of the mains voltage and secure against
reconnection.
– Using suitable means, test the power supply is disconnected.
▶ The product requires different voltages.
Do not connect the extra-low voltage side to the mains voltage or vice
versa.
▶ Also observe connection diagrams of other system components.
Handover to the end user
When handing over the heating system, explain the operating conditions
to the user.
▶ Explain how to operate the heating system, with particular emphasis
on all safety-related actions.
▶ Explain that conversions or maintenance must only be carried out by
a suitably qualified engineer.
▶ Point out the need for inspections and maintenance for safe and
environmentally friendly operation.
▶ The installation and operating instructions must be given to the end
user for safekeeping.
Damage caused by frost
The system can freeze if it is switched off:
▶ Observe the notices regarding frost protection.
▶ Due to the additional functions, e.g. DHW heating or anti-seizing
protection, the system should always be left on.
▶ Correct any faults immediately.
2 Product details
The module is designed to control cascade systems. A cascade system is
a heating system in which several heat sources are used to obtain greater
heat output. In this connection, see for example the wiring diagram on
page 86.
• The module is used to activate the heat source.
• The module is used to record external, flow and return temperature.
• Configuration of the cascade system with a user interface with an
plus BUS interface EMS 2/EMS (not possible with all user
interfaces).
The combination options for the modules are shown in the connection
diagrams.
2.1

Important information on use

The module communicates via an EMS 2 / EMS plus interface with other
EMS 2 / EMS plus-enabled BUS nodes.
If the speed is too low heat when the burner is started in heat
sources with a variable speed pump, high temperatures and
frequent burner cycles can arise.
▶ If possible, configure the pump to On/Off mode with
100 % output, otherwise set minimum pump output to
the highest possible value.
• The module can be connected to user interfaces with a EMS 2 / EMS
plus (Energy Management System) BUS interface. Alternatively, an
external output demand or temperature demand can be connected
via the 0-10 V interface on the module.
• The module only communicates with heat sources with EMS, EMS 2,
EMS plus and 2-wire BUS (HTIII) (with the exception of heat sources
of product series GB112,GB132, GB135, GB142, GB152).
• Only connect heat sources from a single manufacturer in the system.
• Only use heat sources in a system with either gas or oil as the energy
source (heat pumps with a EMS 2 / EMS plus BUS interface are not
allowed).
6 720 816 739 (2015/05)
• The installation space must be suitable for the IP rating stated in the
module specifications.
• If a DHW cylinder is connected directly to a heat source:
– The system controller or 0-10 V controller does not display any
information about the DHW system and does not influence the
DHW heating.
– With direct DHW heating, it is recommended that a cylinder
smaller than 400 litres is used.
– The domestic hot water including thermal disinfection is
controlled directly by the heat source.
– Thermal disinfection may have to be monitored manually.
Observe the heat source instructions.
– If it is not possible to monitor thermal disinfection at the device,
do not connect a DHW cylinder directly to a heat source.
2.2

Function description / control strategies

2.2.1

Serial standard cascade

The connected heat sources/modules are turned on and off according to
the wiring.
For example, the heat source is connected to the BUS1 terminal as the
first terminal, the heat source is connected to the BUS2 terminal as the
second terminal, etc.
If the heat source is turned off, the sequence is reversed. The heat
source which was connected last is turned off first.
The controls take into account that the performance increases or
decreases suddenly when a heat source is connected or disconnected.
2.2.2

Serial optimized cascade

The aim of this control strategy is to operate the heat source with
equivalent burner runtimes.
The connected heat sources are turned on and off according to the
burner runtime. The burner runtimes are compared every 24 hours, and
the sequence is reestablished.
The heat source with the shortest burner runtime is connected first, and
the one with the longest runtime is connected last.
If the heat source is turned off, the sequence is reversed. The heat
source which was connected last is turned off first.
The controls take into account that the performance increases or
decreases suddenly when a heat source is connected or disconnected.
2.2.3

Serial cascade with peak load coverage

This control strategy is recommendable when the heat energy demand is
even over a long time (base-load output) with brief peaks (peak load).
The heat sources connected to terminals BUS1 and BUS2 cover in the
base-load output. The heat sources at terminals BUS3 and BUS4 are
connected to cover and the energy demand in peak loads.
The heat sources at terminals BUS3 and BUS4 are connected when the
required flow temperature rises above an adjustable limit, or the outside
temperature falls below an adjustable limit.
If the heat source is turned off, the sequence is reversed. The heat
source which was connected last is turned off first.
The controls take into account that the performance increases or
decreases suddenly when a heat source is connected or disconnected.
2.2.4

Parallel cascade

This control strategy should be used when the heat sources have a
similar degree of modulation.
The heat sources are operated with burner runtimes that are as close as
possible. Generally, all heat sources in operation. When all heat sources
are running at minimum performance, they are also operated modulated
to the same extent.
MC 400