Viessmann FB2A Installation And Service Instructions For Contractors page 104

Troubleshooting
Repairs
(cont.)
Checking the solar control module fuse
1. Switch OFF the power.
Extension kit for heating circuit with mixer
Note
The DIP switch on the PCB of the exten-
sion set must be set to "2".
Checking the rotational direction of
the mixer motor
After being switched on, the boiler imple-
ments a self-test. During this, the mixer
is opened and closed again.
104
2. Check fuse A in the solar control
module (see connection and wiring
diagram).
Note the rotational direction of the mixer
motor during its self-test.
Then set the mixer manually to "Open"
again.
Note
The flow temperature sensor must now
capture a higher temperature. If the tem-
perature drops, either the motor is turn-
ing in the wrong direction or the mixer set
is incorrectly fitted.
Mixer installation instructions