Viessmann Vitocal 242-S Installation And Service Instructions Manual page 55

Electrical connection
Terminals Function
X3.8 Frost stat and/or contact
X3.9 humidistat
or
Jumper
X3.18 Heat pump control unit
X2.1 supply 230 V~
X1.1
Internal unit: Controller and sensor PCB (sensors)
Set the required parameters during com-
missioning; see from page 83.
Plug Sensor
F0.1/F0.2 Outside temperature sensor
F0.2/F0.3 Radio clock receiver
F4 Buffer temperature sensor, top
F11 Contact humidistat 24 V–
Note
If a 230 V~ contact humidistat (connection at X3.8/X3.9)
is used for cooling, insert a jumper, otherwise the heat
pump will not start (message "CA Protectn device prim-
ry").
F13 System flow temperature sensor (downstream of heating
water buffer cylinder)
F14 Flow temperature sensor, cooling circuit (heating circuit
without mixer A1/HC1 or separate cooling circuit SKK)
F16 Room temperature sensor for separate cooling circuit
SKK (required) or for heating/cooling circuit without mixer
A1/HC1 (recommended)
F21 Collector temperature sensor
F23 Return temperature sensor, solar circuit
(cont.)
Explanation
Requires zero volt N/C contact:
■ Closed: Continuous safety chain
■ Open: Safety chain interrupted; heat
pump shut down
■ Breaking capacity 230 V~, 0.15 A
■ Remove jumper when making this con-
nection.
■ Connected in series if both safety com-
ponents are installed.
See chapter "Power supply".
Installation sequence
Type
NTC 10 kΩ
DCF
NTC 10 kΩ
―
NTC 10 kΩ
NTC 10 kΩ
NTC 10 kΩ
NTC 20 kΩ
NTC 10 kΩ
55