The flow meter is fine but the system shows no data

What if the BFU does not provide error codes, but the system still doesn't collect data?

There should be an audible click of the relay for every unit (per POSITIVE m3 or kWh). Each of these is a pulse. The frequency of pulses should not be more than 10 per second. 

In case the flow meter does not send pulses, check the following:

1. M79 is set to:
   1. In case of not having temperature sensors: '9. Pos Int Pulse'
   2. In case of having temperature sensors:  12. Energy POS Pulse
2. M31 displays '0. m3/h', or '1. l/h', depending on the set-up needed for your installation based on the expected volume that flows through the pipes.
3. M30 displays '0. Metric'
4. M45 (scale factor) is set to 1
5. M32 displays m3
6. (only in case temperature sensors included): M06 - Check whether the observed temperature signal is sensible