Viessmann FB2B Installation And Service Instructions Manual page 133

External extensions (accessories)
Extension EA1
DE1 Digital input 1
DE2 Digital input 2
DE3 Digital input 3
0 - 10 V 0 - 10 V input
fÖ Power supply [terminals]
fÖA Power supply terminal for addi-
tional accessories
Function description
(cont.)
aBJ
Central fault message/feed
pump/DHW circulation pump
(zero volt)
aVG KM BUS
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