9.2.3 Checking The Magnesium Anode - Buderus SF300/5 Installation And Maintenance Instructions Manual

B In the case of soft water:
Check the cylinder interior regularly and clean out any sediment
deposits.
-or-
B 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).
B Clean out the DHW cylinder interior with a water jet
( Fig. 20, page 50).
B Remove the residues with a wet & dry vacuum cleaner with plastic
suction hose.
B Close the inspection aperture with a new gasket
( Fig. 21, page 50).
B Re-commission the DHW cylinder (

9.2.3 Checking the magnesium anode

The DHW warranty is void if the magnesium anode is not
correctly maintained.
The magnesium anode is a sacrificial anode, which is consumed as the
solar storage tank is used.
We recommend that the protection current is measured annually using
an anode tester ( Fig. 23, page 51). The anode tester is available as
an accessory.
Never bring the magnesium anode surface into contact
with oil or grease.
B Keep everything clean.
B Shut off the cold water inlet.
B Depressurize the DHW cylinder (
B If LAP is present:
– Depressurize the heating-side of the system
– Disconnect LAP on feed and return side
B Install and test the magnesium anode (
page 51).
B Replace the magnesium anode if its diameter has been reduced to
below 15 mm.
B Check the transition resistance across the earth connection and the
magnesium anode.
Pos. Description
1 Magnesium anode
2 Seal
3 Feed-through part
4 Washer
5 Serrated washer
6 Cable lug with earth cable
7 Handhole cover
Table 8 Install magnesium anode (
SF300/5, SF400/5 – 6 720 800 028 (2012/05)
chapter 6, page 11).
Fig. 15, page 49).
Fig. 23 to Fig. 25,
Fig. 26, page 51)
Servicing 9
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