Notes On Installation And Operation; Standards, Regulations And Directives; Duty To Obtain A Permit And Provide Notification; Hydraulic Connection To The Heating System - Bosch Uni Condens 8000 F Installation And Maintenance Instructions Manual

5

Notes on installation and operation

5.1

Standards, regulations and directives

Observe all technical guidelines, country-specific regulations and
standards applicable to installation and operation. These include:
• Local Building Regulations concerning boiler room installations.
• Local Building Regulations regarding air supply and extraction
equipment as well as chimney connection.
• The local regulations regarding chimneys. At least according to
EN 13084.
• Requirements for the electrical connection to the power supply
(such as BS 7671 and EN standards).
• The technical rules of the gas supplier regarding the connection of the
gas burner to the local mains gas supply.
• Regulations and standards regarding the safety equipment level of
water-filled heating systems.
• The safety equipment must at least meet the requirements of BS
EN 12828:2012. Also observe country-specific regulations if these
specify further requirements.
5.2

Duty to obtain a permit and provide notification

In several countries, areas or regions, certain notifications, approvals
and/or rights may be required. Prior to installation, check the approval
requirements, e.g.:
▶ Make sure that the local gas supplier has been notified about the gas
boiler installation and that this has been approved.
▶ Make sure that the regional approvals required for the flue system
and condensate connection to the public sewage system have been
obtained.
▶ Make sure that prior to commencing installation the relevant bodies
(e.g. the local flue gas inspector) and the water board have been
informed.
5.3

Hydraulic connection to the heating system

▶ If the operating temperatures are different, use both return
connectors RK1 (top) and RK2 (bottom).
▶ Connect heating circuits with low return temperatures to connector
RK1.
▶ Connect heating circuits with high return temperatures to connector
RK2.
For an optimum energy yield, we recommend supplying a flow rate of
> 10 % of the total nominal flow rate via connector RK1. In this case, the
return temperature must be below the dew point.
If there are no varying return temperatures, the return at connector RK1
needs to be connected.
▶ Restrict the flow rate in the boiler to a temperature difference of at
least 7 K.
If the system is equipped with a dirt separator, it is not necessary to
restrict the temperature difference.
▶ Size the pump correctly.
Uni Condens 8000 F – 6720867056 (2016/10)
High flow rates and oversized pumps can result in the accumulation of
sludge or deposits on the heat exchanger surfaces.
▶ Before connecting the boiler, flush sludge and dirt out of the heating
system.
▶ Ensure that no oxygen enters the heating water during operation.
▶ Whenever possible, operate the boiler in sealed unvented systems.
If the boiler is nonetheless used in an open vented heating system,
additional measures are required to protect against corrosion and
prevent sludge entering the boiler. The technical safety devices also
require to be matched (equipment and settings).
▶ Consult the manufacturer's sales or service department.
Notes regarding cascade systems:
▶ Carry out the fitting of the boiler circulation pumps (volume flow) in
accordance with the set boiler output.
▶ In the case of parallel switching of the boilers, maintain the same
temperature difference for all boilers.
5.4

Pressure maintenance

If using pump-controlled pressure maintaining systems, pressure
fluctuations will result. They can occur very frequently depending on the
design of the system and the appliance settings. Even if these pressure
fluctuations appear small, if they occur very frequently they may cause
considerable damage to the boiler, as it is designed for a predominantly
static pressure load.
To protect against damage:
▶ Size the expansion vessels correctly.
▶ Ensure that every heat source is equipped with an individual
expansion vessel (individual protection).
▶ Do not connect expansion vessel only to a return connection
(e.g. in systems where a heating circuit is not connected to the
connector RK2).
▶ Connect expansion vessel as shown in fig. 43, page 39.
▶ Set the pre-charge pressure of the expansion vessel according to p0
of the automatic pressure maintaining system.
Floor standing Diaphragm expansion vessel [l]
condensing boiler
UC8000F 800
UC8000F 1000
UC8000F 1200
Table 10 Recommended minimum volumes of expansion vessels
To guarantee the pressure relief valve is used as determined, there must
be a 10 % difference between the excess pressure of the pressure relief
valve and the final pressure of the pressure maintaining system, and this
must not be set to less than 0.5 bar.
Notes on installation and operation
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