Viessmann Vitocal 300-G Installation And Service Instructions Manual page 175

PCB 1: Message and safety components
q¢R Fault message, lag heat source,
zero volt contact closed: Appli-
ance operational (delivered con-
dition: jumper fitted)
q¢T Brine pressure limiter, frost
stat (insert jumper, if no safety
element is connected)
q¢Z Power-OFF (jumper fitted in the
delivered condition, remove jum-
per if making this connection,
contact closed: Safety chain has
continuity, appliance opera-
tional)
Connection markings
Terminal strip X1:
Terminals 1X1.1 to 1X1.?
Terminal strip X2:
Terminals 1X2.1 to 1X2.N
Terminal strip X3:
Terminals 1X3.1 to 1X3.18
Message and safety connections at PCB 1 (cross connect circuit board)
Function
Fault message, lag heat
source
External demand to the
heat pump; mixer OPEN;
operating mode change-
over
Connection and wiring diagrams
q¢U Flow limiter (jumper fitted in the
delivered condition, remove jum-
per if making this connection,
outside the safety chain)
q¢I Appliance fuse F1 ( 6,3 A (slow))
q¢O Mains power directly from the
mains terminal (test point)
For PCB overview, see from page 61.
Note
Total load of all electrical connec-
tions max. 1000 W.
Neutral conductor and earth con-
ductor are connected to terminal
strips X1 and X2.
Terminals may already have been
allocated (subject to appliance ver-
sion). If this signal is required exter-
nally, completely remove the core or
remove and insulate the core end;
alternatively use a twin wire ferrule.
Explanation
Connect zero volt contact on site:
Closed = no fault
Open = fault
Breaking capacity 230 V, 0,1 A
Delivered condition: Jumper fitted
Connect zero volt contact on site:
Closed = demand
Open = no demand
Breaking capacity 230 V, 0,1 A
(cont.)
Connection
1X3.11
1X3.10
1X3.13
1X3.12
or to exter-
nal exten-
sion H1
175