Viessmann VITOCAL 300-G Installation And Service Instructions Manual page 226

Connection and wiring diagrams
Overview of the PCBs and connection options
Message and safety connections
Terminals Function
X3.1 Phase switched
X3.2 External blocking, mixer
X3.14 CLOSED
or to exter-
nal exten-
sion H1
X3.3 Flow switch, well circuit
X3.4
X3.6 Power-OFF
X3.7
X3.8 Primary circuit pressure
X3.9 switch and/or frost stat
or
Jumper
X3.10 Fault message, lag heat
X3.11 pump in a cascade
or
Jumper
226
Explanation
Zero volt contact required:
■ Closed: Blocking enabled
■ Open: No blocking
■ Breaking capacity 230 V~, 2 mA
Connect on site
Zero volt contact required:
■ Closed: Heat pump operational
■ Open: Heat pump shut down
■ Breaking capacity 230 V~, 0.15 A
Connection on site; remove jumper when
connecting
Zero volt contact required:
■ Closed: No blocking (safety chain has
continuity)
■ Open: Blocking enabled
■ Breaking capacity 230 V~, 0.15 A
Connection on site; remove jumper when
connecting
Zero volt contact required:
■ Closed: Safety chain has continuity
■ Open: Safety chain interrupted; heat
pump shut down
■ Breaking capacity 230 V~, 0.15 A
Connect on site:
■ Connected in series if both safety com-
ponents are installed
■ Insert jumper if no safety compo-
nents are installed
Zero volt contact required:
■ Closed: No faults
■ Open: Fault
■ Breaking capacity 230 V~, 0.15 A
Connection on site; remove jumper when
connecting
(cont.)