Viessmann B2TA, Installation And Service Instructions For Contractors

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97
Mixer extension kit
Checking the setting of rotary selector S1
The rotary selector on the PCB of the extension kit
defines the assignment to the relevant heating circuit.
Heating circuit Rotary selector S1
setting
Heating circuit with mixer M2
(heating circuit 2) 2
2 3
4
5
6
1
0
9
8
7
Heating circuit with mixer M3
(heating circuit 3) 4
4 2 3
5
6
1
0
9
8
7
Checking the rotational direction of the mixer
motor
After being switched on, the boiler implements a self-
test. During this, the mixer is opened and closed again.
Note
The mixer motor can also be started via the actuator
test (see chapter "Checking outputs").
Observe the rotational direction of the mixer motor dur-
ing its self-test.
Then manually set the mixer back to "Open".
The flow temperature sensor must now capture a
higher temperature. If the temperature drops, either
the motor is turning in the wrong direction or the mixer
insert is incorrectly fitted.
Mixer installation instructions
Changing the rotational direction of the mixer motor (if required)
gS
BU
|
~
Fig. 67
1. Remove the upper casing cover of the extension
kit.
Danger
An electric shock can be life-threatening.
Before opening the boiler, disconnect it from
the mains voltage, e.g. at the fuse or mains
isolator.
2. At plug
gS
, swap the cores at terminals "
|
" and
"
~
".
3. Refit the casing cover.
Check flow temperature sensor
10
1
10 30 50 70 90 110
Temperature in °C
0.4
0.6
0.8
2
4
6
8
20
Resistance
in kΩ
Fig. 68 Sensor type: NTC 10 k
Ω
1. Disconnect plug
?
(flow temperature sensor).
2. Check the sensor resistance and compare it to the
curve.
In the event of severe deviation replace the sensor.
Troubleshooting
Maintenance
(cont.)
5773 216 GB
Diagnosis