Viessmann BWT 241.A Series, Installation And Service Instructions Manual

Page: 42 / 124

42
Terminals Function Explanation
X3.8
X3.9
P
Pressure switch, primary
circuit
and/or Floating contact required:
■ Closed: Safety chain has continuity
■ Open: Safety chain interrupted; heat
pump shut down
■ Breaking capacity 230 V~, 0.15 A
On-site connection:
■ Connected in series if both safety com-
ponents are installed
■ Insert jumper if no safety compo-
nents are installed
Frost stat
or
Jumper
X3.17
X3.18 Fuse F1 6.3A (slow)
Controller and sensor PCB
Set the required parameters during com-
missioning; see from page 59. Plugs F11, F17:
Nothing should be connected to plugs
F11 and F17 on site.
Sensors
Plug
Sensor Type
F0 Outside temperature sensor; connect on site Ni 500
(PTC)
F4
(X5.6/X5.7) Buffer temperature sensor, top; connect on site Pt 500
(PTC)
F13 System flow temperature sensor (with sensor well, down-
stream of heating water buffer cylinder); connect on site Pt 500
(PTC)
F14 Flow temperature sensor, cooling circuit (direct heating
circuit A1 or separate cooling circuit); connect on site Ni 500
(PTC)
F16 Room temperature sensor for separate cooling circuit
(requirement) or for direct heating/cooling circuit (recom-
mendation); connect on site Ni 500
(PTC)
F18
(X6.6/X6.7) Return temperature sensor, solar circuit; connect on
site Pt500
(PTC)
F21 Collector temperature sensor; connect on site Pt500
(PTC)
Installation sequence
Electrical connection
(cont.)
5601 598 GB