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5833 275 - 04
Vitotrans 300 Installation, Operating and Service
Service
Temperature Sensors
Temperature
Resistance in k ohms
Temperature
Resistance in k ohms
Temperature sensor (NTC 10k
)
Temperature sensor (NTC 20k
)
1. Locate the sensor in the junction box and remove leads.
2. Check the sensor resistance and compare it with the
curve.
3. In the case of severe deviation, check the installation
and replace the sensor if required.
Flow Sensor
Blk (1)
Red (2)
Wht (3)
Line
Volts
0-10V DC
Common
Hot +
U Output
24V AC/DC Transformer
Operation
The ultrasonic flow meter is an accurate repeatable
liquid flow measurement meter by utilizing ultrasonic
transit time technology. The transducers perform as
both emitter and receiver to provide accurate signal
reflection.
0V
Sensor has no supply voltage
0.3V Sensor has supply voltage but is in error state
0.5V Zero flow
10V
Maximum flow
DHW temperature sensor
The DHW temperature sensor is a dual core NTC 10K /
NTC 20K sensor.
The boiler return temperature sensor
- single core NTC 10K sensor.
The DCW temperature sensor
- single core NTC 10K sensor.
The DHW storage tank temperature sensor
- single core NTC 10K sensor.
1. Locate the sensor in the junction box and remove leads.
2. Check the sensor voltage (0-10VDC) signal.
3. In the case of severe deviation, check the installation
and replace the sensor if required.
DC
V
o
lt
age
Flow
