Buderus 600-19R Installation And Servicing Instructions page 34

5 Servicing
Code Meaning
4F
Safety sensor exceeds 95 °C
Possible
cause
1 Resistance in the installation is too high
2 Heating capacity is too large for the installation
3 Safety sensor is faulty
4 Problem with the pump or pump cabling (no circulation)
5 Water pressure is too low in the installation
Code Meaning
4L
Short circuit in safety sensor
Possible
cause
1 Safety sensor is faulty
2 A short or bad connection in the cable harness
3 UBA might be faulty
Code Meaning
4P
Safety sensor has a loose connection or is defective
Possible
cause
1 Safety sensor faulty or disconnected
2 A short or bad connection in the cable harness
3 UBA might be faulty
Code Meaning
4U
Short circuit in flow sensor
Possible
cause
1 Flow sensor is dirty or faulty
2 A short or bad connection in the cable harness
3 UBA might be faulty
Subject to modifications resulting from technical improvements!
34 Installation and maintenance instructions for wall-mounted condensing gas boiler Buderus 600 - 11R/19R/24R • 05/2004
Action
Check if not all (thermostatic) radiator valves are clogged
with dirt
Adjust the heating capacity
Check the sensor and 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)
Check if the pump cabling is faulty or if the pump is stuck
Top up the system
Action
Check the sensor and 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)
Check the cable harness and/or connector of the sensor
Check the UBA by temporarily connecting a different UBA
(see subsection 5.3.3)
Action
Check the sensor and 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)
Check the cable harness and/or connector of the sensor
Check the UBA by temporarily connecting a different UBA
(see subsection 5.3.3)
Action
Check the sensor, replace if necessary (see subsection
5.3.11, subsection 5.3.12, subsection 5.3.13)
Check the cable harness and/or connector of the sensor
Check the UBA by temporarily connecting a different UBA
(see subsection 5.3.3)
Boulter Buderus Ltd. • http://www.boulter-buderus.co.uk