Blumfeldt Wasserwerk 250 Manual De Instrucciones página 19

EN
Battery
If the pump stops working after about 12 - 18 months in operation, the reason
could be that the battery life has been exhausted. Open the housing according
to the illustration and replace the battery with a model with the same
specifications (6 V, 4 aH):
Screw
Housing Battery Circuit board Front
19