Buderus SM400/5E Installation And Maintenance Instructions Manual page 25

We recommend that insulated magnesium anodes are additionally
checked regarding the protective current using an anode tester on an
annual basis ( Fig. 24, page 111). The anode tester is available as an
accessory.
Never bring the magnesium anode surface into contact
with oil or grease.
▶ Keep everything clean.
▶ Shut off the cold water inlet.
▶ Depressurize the DHW cylinder ( Fig. 17, page 109).
▶ Install and test the magnesium anode ( Fig. 25 to Fig. 28,
page 111).
▶ Replace the magnesium anode if its diameter has been reduced to
below 15 mm.
▶ Check the transition resistance across the earth connection and the
magnesium anode.
SU300/5 | SU400/5 – 6 720 800 019 (2015/04)
Maintenance 9
25