Additional Troubleshooting Information; Power Supply For The Vr 70, Vr 71; Checking The Ebus Power Supply; Faulty Ebus Communication - Vaillant MultiMatic 700/2 Product Training

multiMATIC 700/2
6.4

Additional troubleshooting information

6.4.1

Power supply for the VR 70, VR 71

The VR 70 and VR 71 modules have a green LED on the PCB. When this LED is lit up,
the module is being supplied with a voltage of 230 V and the internal power supply unit
is working.
6.4.2

Checking the eBUS power supply

The eBUS power supply powers the boiler connected to the controller. A DC voltage of
20 - 24 V should be measured at the "BUS " terminals.
As you know, the same polarity between boiler and eBUS accessories does not need
to be taken into account.
6.4.3

Faulty eBUS communication

If there is no eBUS communication for more than 15 minutes, all functions and outputs
of the accessory module in question are switched off.
6.4.4

No display, VRC 700 (built into the electronics box) not working

With this kind of fault there is the possibility that the 3-pin plug connector between the
appliance switch cabinet and the controller has been forgotten or the contacts are bent.
6.4.5

Blank display (controller in living room)

One possible cause may be direct sunlight on the display. The controller functions are
not affected. The problem can be rectified by switching the power off and on. A now
location should be found.
Notes
10/2015 101 Training 0020228700_00