Internal Extensions - Viessmann FB2B Installation And Service Instructions Manual

Control unit
(cont.)
Boosting DHW heating
The booster heating function is activated
if a switching period is selected for the
fourth time phase.

Internal extensions

Internal extension H1
The internal extension H1 is integrated
into the control unit casing. The cylinder
primary pump is connected to relay out-
put sK.
Function description
The set temperature value for the heat-
ing boost is adjustable in coding address
"58".
An external safety valve can be connec-
ted to gD
129