Buderus SM400/5E, Installation And Maintenance Instructions Manual

Page: 24 / 116

7 Shutting down
SU300/5 | SU400/5 – 6 720 800 019 (2015/04) 24
7 Shutting down
▶ If an immersion heater has been fitted (accessory), isolate the DHW
cylinder from the power supply (

Fig. 16, page 109).
▶ Switch off the temperature controller at the control unit.
▶ Drain the DHW cylinder (

Fig. 16 and 17, page 109).
▶ Decommission all assemblies and accessories of the heating system
as specified in the manufacturer's technical documentation.
▶ Close the shut-off valves (

Fig. 18, page 110).
▶ Depressurize the indirect coils.
▶ Drain and blow out the indirect coils (

Fig. 19, page 110).
▶ To prevent corrosion, dry out the interior and keep the inspection
aperture covers open.
8 Environmental protection/disposal
Environmental protection is a fundamental principle of the
Bosch Group.
Quality of products, efficiency and environmental protection are equally
important objectives for us. All legislation pertaining to the environment
is strictly observed.
Packaging
We are dedicated in adhering to country-specific disposal standards as
they relate to packaging to ensure optimum recycling. All packaging
materials are environmentally compatible and can be recycled.
Used appliances
Used appliances contain materials that should be recycled.
The assemblies are easy to separate and the types of plastic used are
identified. This allows the various assemblies to be appropriately sorted
for recycling or disposal.
9 Maintenance
▶ Let the DHW cylinder cool down sufficiently prior to any maintenance
work.
▶ Carry out cleaning and maintenance procedures in the specified
intervals.
▶ Remedy all faults immediately.
▶ Only use genuine spare parts.
9.1 Maintenance intervals
Service the appliance in accordance with throughput, operating
temperature and water hardness (

Table 7, page 24).
The use of chlorinated DHW or a water softener unit reduce the service
intervals.
You can check the local water quality with your water supply utility.
Depending on the composition of the water, it can make sense to deviate
from the reference values listed.
9.2 Maintenance work
9.2.1 Checking the safety valve
▶ Check the safety valve annually.
9.2.2 Descaling/cleaning the DHW cylinder
▶ Disconnect the DHW cylinder on the DHW side from the pipework.
▶ Close the shut-off valves and isolate the immersion heater from the
power supply (if installed) (

Fig. 18, page 110).
▶ Drain the DHW cylinder (

Fig. 17, page 109).
▶ Check the DHW cylinder interior for contamination (lime scale
deposits, sediment).
▶ In the case of soft water:
Check the cylinder interior regularly and clean out any sediment
deposits.
-or-
▶
In the case of hard water or severe contamination:
Regularly descale the DHW cylinder in line with the actual amount of
limescale using chemical cleaning methods (e.g. with a suitable
descaling agent based on citric acid).
▶ Clean out the DHW cylinder interior with a water jet
(

Fig. 21, page 110).
▶ Remove the residues with a wet & dry vacuum cleaner with plastic
suction hose.
▶ Close the inspection aperture with a new gasket
(

Fig. 22, page 111).
▶ Re-commission the DHW cylinder (

chapter 6, page 23).
9.2.3 Checking the magnesium anode
The magnesium anode is a sacrificial anode that is consumed when the
DHW cylinder is in use. Two types of magnesium anode can be used.
Fitted as standard: A non-insulated magnesium anode (

Version A,
Fig. 26, page 111).
Available as an accessory: An insulated magnesium anode (

Version
B, Fig. 26, page 111).
WARNING: Scalding from hot water!
▶ Let the DHW cylinder cool down sufficiently.
Water hardness in °dH 3 – 8.4 8.5 – 14 > 14
Calcium carbonate
concentration in mol/ m³
0.6 – 1.5 1.6 – 2.5 > 2.5
Temperatures Months
At a standard throughput (< cylinder content/24 h)
< 60 °C 24 21 15
60 – 70 °C 21 18 12
> 70 °C 15 12 6
At a higher throughput (> cylinder content/24 h)
< 60 °C 21 18 12
60 – 70 °C 18 15 9
> 70 °C 12 9 6
Table 7 Service intervals in months
In order to improve the cleaning effect, heat up the
indirect coils prior to cleaning them with a water jet. The
thermal shock effect separates deposits (e.g. lime scale
build-up) more readily.
The DHW warranty is void if the magnesium anode is not
correctly maintained.