Buderus 800 - 5.3.5 Replacing the UBA

Servicing 5
Wall-mounted condensing gas boiler Buderus 800 - Subject to modifications resulting from technical improvements!
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5.3.4 Check combustion air/flue gas system and hose
connections
 Check combustion air/flue gas system for blockages.
5.3.5 Replacing the UBA
 Disconnect system from power supply by removing
main fuse or power connection plug.
 Swivel the UBA to one side and pull the four-pin plug
of the mains power switch out at the back of the UBA.
 Disconnect all plug-in cables. Note the position of
each plug-in cable.
 Loosen the three screws on the UBA and remove it.
 Remove mains power switch and fit to new UBA.
 Screw the replacement UBA into position.
 Reconnect all plug-in cables to their correct sockets.
 Fit the casing.
 Connect system to mains power supply.
 Move mains power switch to “I”.
fig. 56 Checking combustion air/flue gas system and
hose connections
fig. 57 Replacing the UBA