Technical data

48 Installation and servicing instructions for wall-mounted condensing gas boiler Buderus 600 - 11R/19R/24R • 02/2006
Buderus • http://www.buderus-domestic.co.uk Subject to modifications resulting from technical improvements!
Servicing5
Code Meaning
2U Temperature difference between flow and return more than 55 °C
Possible
cause
Action
1 Flow sensor is dirty or faulty Check the sensor, replace if necessary (see subsection
5.3.11, subsection 5.3.12, subsection 5.3.13)
2 Problem with the pump or pump cable (flex)
(no circulation)
Check if the pump cable (flex) is faulty or if the pump is
stuck. Replace pump if necessary.
3 Water pressure is too low in the installation Top up the system
4 Resistance in the installation is too high Check if (thermostatic) radiator valves are closed or
clogged with dirt
5 Safety sensor is dirty or faulty Check the safety sensor for dirt. Measure if resistance over
the sensor is correct. If not replace safety sensor (see
subsection 5.3.8, subsection 5.3.9, subsection 5.3.10)
Code Meaning
3C Bad plug-in connection at cable harness, or damaged wiring
Possible
cause
Action
1 Cable harness is faulty Check cable harness for faults and bad connections
2 Connectors at the back of the UBA are loose or faulty Check the connectors at the back of the UBA
3 UBA might be faulty Check the UBA by temporarily connecting an other UBA
(see subsection 5.3.3)
Code Meaning
4A Flow sensor exceeds 100 °C
Possible
cause
Action
1 Flow sensor is dirty or faulty Check the sensor, replace if necessary (see subsection
5.3.11, subsection 5.3.12, subsection 5.3.13)
2 There is a problem with the pump or pump cable (flex)
(no circulation)
Check if the pump cable (flex) is faulty or if the pump is
stuck. Replace pump if necessary.
3 Water pressure is too low in the installation Top up the system
Code Meaning
4C F2 fuse malfunction, or flue gas thermostat active
Possible
cause
Action
1 Water pressure is too low in the installation Top up the system
2 Heat exchanger is dirty Check for a dirty heat exchanger and clean if necessary.
(see subsection 4.1)
3 Flue gas retarder faulty or missing Check if the flue gas retarder is installed in the heat
exchanger
4 Heat exchanger has a problem Purge heat exchanger