Connecting The Venting System; Fitting A Sealing Collar (Accessory); Connecting The Boiler To The Pipework - Bosch Uni Condens 8000 F Installation And Maintenance Instructions Manual

Installation
When sizing and implementing the flue system, comply with the
following requirements:
• The flue system must be made of corrosion resistant material.
• The flue system must have the necessary approval for operation with
a floor standing condensing boiler.
• Size flue systems in accordance with the respective national and local
regulations and applicable standards.
• The flue system must be sized according to the modulation range of
the burner.
• When selecting the material for the flue system, take into account the
composition and temperatures of the flue gas to prevent damage and
contamination of the system components that are in contact with flue
gas.
• Only flue systems which are approved for a flue gas temperature of at
least 120 °C, may be used.
• Route the flue gas as directly as possible to the chimney considering
the best possible flow characteristics (e.g. short, rising, and with the
fewest possible bends). Provide a separate chimney flue for each
boiler. Take the thermal expansion of the system into account.
• Implement deviations in the connection pieces as favourably as
possible where flow is concerned by using bends or deflectors.
Connection pieces with several deviations should be avoided, as they
would have a detrimental effect on air-borne and structure-borne
noise as well as the start-up pressure surge. Prevent sharp-edged
joints between rectangular connection flanges and the connection
pipe. Likewise with any reductions/expansions that may be required,
the angle of the joint should not exceed 30°.
• Where possible, connection pieces should be joined to the chimney
in such a way as to optimise the flow and have as steep an incline as
possible (at an angle less than 45°). Existing terminal pieces at the
chimney outlets must ensure the free discharge of flue gas into the
open air.
• Any condensate must be able to drain freely over the entire length
and be treated and disposed of in accordance with local regulations.
• The inspection apertures must be provided in accordance with local
regulations.
• The chimney must be separated from the boiler (e.g. with
compensators) to prevent the transfer of structure-borne noise.
• If a flue gas damper is installed in the flue system, integrate an
"OPEN" limit switch into the boiler control system for safety reasons.
Combustion must only be able to start when the feedback from the
limit switch confirms that the flue damper is fully open. A
temperature drop inside the boiler is possible on account of the time
it takes the actuator to move the damper into position. Set the
"CLOSE" limit position at the flue gas damper in such a way that it
never closes fully. This prevents damage to the fitted burner through
heat build up.
• To avoid problems with combustion (start behaviour), the pressure at
the flue gas connector of the boiler must not exceed a negative
pressure of 15 Pa. Fittings in the flues (e.g. secondary air devices)
may need to be provided.
18
Multiple assignment
Several items of combustion equipment may only be connected to a
common flue system (chimney, flue) if they are suitably designed for this
mode of operation and that the following requirements are met:
• The system is sized so that flue gas can be removed without problems
in every operating condition.
• Flue gas is prevented from flowing into combustion equipment that is
currently not in operation during pressurised operation (e.g. due to
gas-tight flue gas dampers).
• Unchanging combustion chamber pressure ratios in each of the
connected heat sources under all operating conditions.
• Take minimum flue gas velocity Wmin according to EN 13084-1
Annex A into account, or to simplify Wmin = 0.5 m/s
• Negative pressure must prevail at the merging points of the
combustion equipment under every operating condition.
Merging of flue gas flows should be avoided whenever possible to ensure
reproducible exhaust gas ratios for each boiler system. If however
merging of flue gas flows cannot be avoided, they must be routed along a
short section of the flue system parallel to and isolated from one another
by a baffle plate to prevent reciprocal effects.
Must not be connected to flue systems to which several items of
combustion equipment are connected:
• Combustion systems operated using LPG.
• Combustion equipment equipped with fan, if not all items of
combustion equipment are installed in the same room.
6.4.2

Connecting the venting system

▶ Connect the connection piece onto the flue outlet and the flue system
(chimney).
▶ Support the connection piece if necessary.
6.4.3

Fitting a sealing collar (accessory)

▶ Fit the sealing collar in accordance with the installation instructions
supplied.
6.4.4

Connecting the boiler to the pipework

NOTICE:
System damage due to leaking connections!
▶ Connect pipes without stress to the boiler connections.
Boiler contamination on the water side is not permissible.
If required to prevent contamination, install a dirt separator in the boiler
return.
Connecting the heating return
The boiler has two inlet options for the return water. If separate system
returns for differing return temperatures are used (e.g. underfloor
heating, DHW heating), these can be routed to the heat exchanger via
separate return connections.
• RK1 = low return temperature (e.g. underfloor heating)
• RK2 = high return temperature (e.g. DHW heating)
On delivery, the return is sealed with a dummy flange. If using connection
RK2:
▶ Remove dummy flange.
If there are no varying return temperatures, return connection RK1 is
used.
▶ Connect the heating system return to the appropriate boiler return
connection RK1/RK2.
▶ Close off unused connections with a plug or dummy flange.
Uni Condens 8000 F – 6720867056 (2016/10)