
G-2 A-070336_EN • B_0821
Table of ConTenTs
Index of IllustratIons ..............................G-4
General InformatIon ...............................G-5
Liabilities of the Manufacturer, the Installer
and the End user ..............................................G-5
About this Manual ............................................G-6
Safety Instructions ...........................................G-7
Package Contents ...........................................G-8
Boiler Marking ..................................................G-8
Product descrIPtIon ...............................G-9
Nesta 120 - 160 - 200 - 250.............................G-9
General Description .................................................G-9
Frost Protection .......................................................G-9
Safety Devices .........................................................G-9
Optional equipment .................................................G-9
Control Panel and Main Functions.................G-12
Symbols and Messages on the Control Panel .G-13
technIcal sPecIfIcatIons ........................G-14
Dimensions and Clearances...........................G-14
Performance and Eciency Data...................G-16
ErP Data .........................................................G-16
Combustion Data ...........................................G-17
Gas Data ........................................................G-18
Electrical Data ................................................G-17
Hydraulic Data................................................G-19
Pressure Drop Curve ......................................G-19
Flow Rate .......................................................G-19
InstructIons for the user......................G-20
Safety Instructions for the User......................G-20
Periodic checks .............................................U-21
Starting the Appliance....................................U-22
Stopping the Appliance..................................U-22
What to Do if... ...............................................U-23
Basic Settings ................................................U-24
Structure of Menus for the End User .............U-27
Product InstallatIon .............................. I-29
Safety Instructions for the Installation............. I-29
Handling the Product ...................................... I-30
Unpacking the Product ................................... I-30
Installing and Preparing the Boiler .................. I-30
Removing and Installing the Access Panels ... I-31
Requirements for the Hydraulic Connections . I-32
Water Quality Requirements to Prevent
Scaling and Corrosion in a Heating System.... I-33
Typical Hydraulic Connections - Heating Circuit.. I-35
Hydraulic Connections - Cascaded boilers,
with External Domestic Hot Water Tank and
Plate Heat Exchanger...................................... I-36
Hydraulic Connections - Cascaded boilers,
with External Domestic Hot Water Tank and
Low Loss Header ............................................ I-37
Safety Instructions for the Chimney Connections I-38
Chimney Connection....................................... I-40
Silencer Installation in Open Chimney Systems (B) . I-41
Engineering the Chimney System ................... I-42
Accessories ..................................................... I-42
Safety Instructions for the Gas Connection .... I-43
Gas Conversion............................................... I-44
Preparing the Boiler for Gas Conversion...................I-45
Adjustment of Fan Speeds.......................................I-46
Combustion Adjustment for Gas Conversion . I-47
Safety Instructions for the Electrical Connections I-49
Connections .................................................... I-49
Accessing the Low Voltage Terminal
Strip and Electronic board............................... I-50
Accessing the High Voltage Terminal Strip ..... I-51
Routing the Cables.......................................... I-51
Wiring Diagram................................................ I-52
commIssIonInG ........................................ I-54
Safety Instructions Before Start-up................. I-54
Filling the System ............................................ I-54
Start-up and Combustion Adjustments .......... I-55
maIntenance........................................... I-56
Safety Instructions for Maintenance ............... I-56
Maintenance Requirements ............................ I-57
Shutting Down for Maintenance...................... I-58
Draining the Boiler........................................... I-58
Restarting after Maintenance .......................... I-58
Cleaning the Condensate Pipe and Trap......... I-59
Removing and Installing the Fan and Air
Adapter Assembly ........................................... I-60
Removing and Installing the Ignition and
Ionization Electrodes ....................................... I-62
Removing and Installing the Burner ................ I-63
Checking and Cleaning the Combustion Chamber
I-64
Replacing the Gas Valve Filter......................... I-64
maIntenance........................................... I-65
Checking the Flue Gas (FPS) and Air (APS)
Pressure Switches operation........................... I-65