Smarter Heating & Hot Water

Vaillant VR33 Module Installation

Complete step-by-step guide to installing the Vaillant VR33 OpenTherm module on your Vaillant ecotec boiler. Follow these instructions to enable OpenTherm control on your heating system.

VR33 module location on a Vaillant PCB VR33 module fitted on a Vaillant ecoFIT boiler
  1. Turn off power to the boiler
  2. Install the VR33 Module on the left hand side as shown

    Your PCB may vary depending on the model.

  3. Connect VR33 X32 to PCB X31. Please note sometimes the correct connector may vary, see the installation manual to determine latest connector.
  4. Link the 24v connection on the PCB with link wire as was provided in the factory supplied state. The connector names vary, but it will be either 24V RT, or a number ie 7,8,9
  5. Connect your OpenTherm thermostat to the OpenTherm connector on the VR33 Module.
  6. Turn on power to the boiler

    Green lights on VR33 Module will flash. To confirm the correct connection you may go to the settings menu and check D.90 (see manual on how to see D.90 for your specific boiler model) for confirmation of recognition of the Ebus VR33 Module.

  7. Enable the OpenTherm connection from your specific thermostat should it be required if it is not automatically detected. ie Nest Thermostats need you to go into the Pro Setup menu.

Other resources

Remove VR33 Module (PDF)