Viessmann VITOCAL 151-A Installation And Service Instructions Manual page 133

Checking the temperature sensors
Temperature sensor NTC 10 k
Outside temperature sensor
■
Cylinder temperature sensor
■
Flow temperature sensor
■
Or
Flow temperature sensor, heating/cooling circuit 1
■
Return temperature sensor
■
External heating water buffer cylinder: Temperature
■
sensor
For indoor unit with 1 integrated heating/cooling cir-
cuit
Room temperature sensor
■
1. Check the lead and plug of the temperature sen-
sor.
2. Disconnect the wires from the plug.
3. Measure the temperature sensor resistance. Com-
pare the resistance with the value for the current
temperature from the following table.
Ω
Connection
Luster terminals for sensors, terminal 5 and 6
■
Plug 1 on the HPMU electronics module
■
Plug 5 on the HPMU electronics module
Cable harness in the indoor unit
■
Position of the temperature sensor: See chapter "In-
■
door unit maintenance: Overview of internal compo-
nents".
Cable harness in the indoor unit
■
Position of the temperature sensor: See chapter "In-
■
door unit maintenance: Overview of internal compo-
nents".
Luster terminals for sensors, terminal 7 and 8
On Vitotrol 300-E
4. If the deviation is > 10 %, disconnect the wires on
the temperature sensor. Repeat the test directly on
the sensor.
If required, check the on-site cable (2-core cable,
max. length 35 m with a cross-section of 1.5 mm
Depending on the test result, replace the lead or
the outside temperature sensor.
Indoor unit maintenance
2
).
133