Inspection And Servicing; Inspection; Maintenance; Maintenance Intervals - Bosch W 500-5 Series Installation And Maintenance Instructions For The Contractor

10 | Inspection and servicing

7 Inspection and servicing
WARNING: Risk of scalding from hot water!
▶ Let the DHW cylinder cool down sufficiently.
▶ Let the DHW cylinder cool down sufficiently prior to any maintenance
work.
▶ Carry out cleaning and maintenance procedures at the specified
intervals.
▶ Remedy all faults immediately.
▶ Only use genuine spare parts.
7.1

Inspection

An inspection of DHW cylinders must be carried out every 2 months in
accordance with DIN EN 806-5. During this the set temperature should
be checked and compared with the actual temperature of the heated
water.
7.2

Maintenance

Annual maintenance should be carried out in accordance with
DIN EN 806-5, Appendix A, tab. A1, line 42. This includes the following
work:
• Functional check of the pressure relief valve
• Leak test of all connections
• Cleaning of the cylinder
• Checking of the anode
7.3

Maintenance intervals

Maintenance must be carried out based on the flow rate, operating
temperature and water hardness ( tab. 9). Based on our many years
of experience, we recommend that service intervals are selected
according to tab. 9.
The use of chlorinated potable water or a water softener unit reduces the
service intervals.
You can check the water quality with your water supply utility.
Depending on the composition of the water, it may be sensible to deviate
from the indicated values given.
Water hardness [°dH]
Calcium carbonate concentration
3
[mol/m ]
Temperatures
At a normal flow rate (< cylinder capacity/24 h)
< 60 °C
60...70 °C
> 70 °C
At an increased flow rate (> cylinder capacity/24 h)
< 60 °C
60...70 °C
> 70 °C
Table 9 Service intervals in months
6 720 821 900 (2017/05)
3...8.4 8.5...14 > 14
0.6...1.5 1.6...2.5 > 2.5
Months
24 21 15
21 18 12
15 12 6
21 18 12
18 15 9
12 9 6
W 500-5 | W 750-5 | W 1000-5 | WS 500-5 E | WS 750-5 E | WS 1000-5 E | WS 400-5 EL | WS 500-5 EL
7.4

Maintenance work

7.4.1

Checking the pressure relief valve

▶ Check the pressure relief valve annually.
7.4.2

Descaling/cleaning the DHW cylinder

In order to improve the cleaning effect, heat up the heat
exchanger prior to cleaning it with a water jet. The
thermal shock effect releases deposits
(e.g. limescale deposits) more readily.
▶ Disconnect the DHW cylinder on the potable water side from the
mains.
▶ Close the shut-off valves and isolate the immersion heater (if used)
from the mains power supply ( Fig. 32, page 53).
▶ Drain the DHW cylinder ( Fig. 33, page 53).
▶ Open the inspection port on the cylinder ( Fig. 37, page 54).
▶ Inspect the interior of the DHW cylinder for contamination
(limescale deposits).
-or-
▶ In the case of soft water:
Check the tank regularly and clean out any limescale 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. 38, page 54).
▶ Use a wet/dry vacuum appliance with a plastic suction pipe to
remove any residues.
▶ Close the inspection port using a new gasket
( Fig. 39 and 40, page 54).
▶ Re-commission the DHW tank ( Chapter 6.1, page 9).
7.4.3

Checking the magnesium anode

The magnesium anode is a sacrificial anode, which is
consumed during the operation of the DHW cylinder.
The DHW cylinder warranty is void if the magnesium
anode is not correctly maintained.
We recommend that the protection current is measured annually using
an anode tester ( Fig. 41, page 55). The anode tester is available as
an accessory.