Technical data

Installation and servicing instructions for wall-mounted condensing gas boiler Buderus 600 - 11R/19R/24R • 02/2006 55

Subject to modifications resulting from technical improvements! Buderus • http://www.buderus-domestic.co.uk

Servicing 5

5.3 Checking and replacing parts

5.3.1 Checking the flue gas thermostat

z Detach plug-and-socket connection on cable to flue

gas thermostat. Ensure that no cable is earthed

(grounded) at any point.

z Allow the flue gas thermostat to cool down. Activation

temperature: Buderus 600 - 11R / 19R / 24R: 105 °C

z Check flue gas thermostat for continuity. If continuity

is not present, the flue gas thermostat is defective.

z Replace any flue gas thermostat found to be defec-

tive. Ensure you use only genuine Buderus spare

parts.

z If the flue gas thermostat is working correctly, plug it

in once more.

5.3.2 Replacing the flue gas thermostat

z Unscrew the flow-backup mounting.

z Detach the cable plug at the flue gas thermostat.

z Loosen both retaining screws on the flue gas thermo-

stat.

z Remove the flue gas thermostat and replace with a

new unit (fig. 48).

z Retighten the retaining screws.

z Reconnect the cable plug.

z Screw the mounting into place.

5.3.3 Replacing the UBA

z Disconnect the system from the power supply.

z Loosen the two screws on the UBA (fig. 49, item 1).

z Carefully turn the UBA around with the backside

facing up (fig. 50).

z Note the position of the cable plugs, disconnect all

cable plugs.

z Fit a new UBA.

z Reconnect all plug-in cables to their correct sockets.

z Turn the UBA around and place back onto the

bracket.

z Tighten the two screws.

z Connect system to mains power supply.

Fig. 48 Buderus 600 - 11R / 19R / 24R :

replacing the flue gas thermostat

Fig. 49 Replacing the UBA

Fig. 50 Backside of the UBA