RVL45.1 Weather-dependent flow temperature controller (AC 220 V) with timeclock. Direct replacement by RVL480, same dimensions and panel cut-out. Sensors and valve actuators can be re-used, QAA22.71 room unit must be replaced (QAW50 or QAW70). RVL480 has many 
Key data to replacement product: features, including optimization, holiday programs, digital display and auxiliary functions. AZY12.1x 'standard' submodule functions and AZY12.2x 'flex' submodule functions are available within RVL480. (If wind or solar influence is required use RVL482, with an external AC 24 V supply for the sensor). 
Info: Do not use the existing base as terminals are different - the 
Key data to replacement product: unit must be rewired.