0020152779_05 - 10/14 - Vaillant21 Safety .......................................................................31.1 Intended use .............................................................31.2 Symbols used............................................................31.3 Qualifications.............................................................31.4 General safety advices..............................................31.5 Intended use .............................................................41.6 Rules and regulations ..............................................41.7 CE Mark ....................................................................52 Notes on the documentation..................................62.1 Observe other applicable documents........................62.2 Storing documents ....................................................62.3 Validity of the instructions ..........................................63 Description of the product .....................................63.1 Product structure .......................................................63.2 Type designation and serial number .........................63.3 Data plate description ...............................................64 Mounting and installation.......................................74.1 Preparing the mounting and installation ....................74.2 Mounting the product ................................................84.3 Hydraulic installation .................................................84.4 Electrical Installation .................................................94.5 Cableway and passage ........................................... 115 Start up...................................................................125.1 Purging the appliance .............................................125.2 Installing the casing.................................................135.3 Handing over the product to the user ......................136 Repair work............................................................136.1 Spare parts..............................................................136.2 Draining the product ................................................136.3 Resetting the Electrical back-up heater ..................136.4 Checking tightness ..................................................146.5 Checking the electrical installation ..........................147 Decommissioning .................................................148 Recycling and disposal ........................................149 Technical data ......................................................14Table of contents