RVL55 Digital heating controller (AC 220 V) with menu card operation, extension of functions available using plug-in modules (AZY55..) and remote operation. Standard version is replaced by RVL480 which has the same dimensions and panel cut-out. All existing sensors can be re-used with the exception of the QAA23.7x room units (see QAA23.71 and QAA23.72 for details). Do not use the existing base as terminals are different - the 
Key data to replacement product: unit must be rewired. 
Info: Bus communication is not possible between RVL55 and 
Key data to replacement product: RVL400 series controllers.