Viessmann VITODENS 300 Service Instructions Manual page 101

Extensions for external connections (accessory)
Internal extension H2
The internal extension is integrated
into the control unit housing. As alter-
native, the following functions can be
connected to relay output sK. The
function is allocated via coding
address 53:
Function description
(cont.)
&
Central fault message (code 53:0)
&
Cylinder loading pump (code 53:3)
&
DHW circulation pump (code 53:1)
&
Heating circuit pump for heating cir-
cuit without mixer (code 53:2)
An interlock for extractors can be con-
nected to connection aBJ.
101