Technical data

Installation and servicing instructions for wall-mounted condensing gas boiler Buderus 600 - 11R/19R/24R • 02/2006 49
Subject to modifications resulting from technical improvements! Buderus • http://www.buderus-domestic.co.uk
Servicing 5
Code Meaning
4F Safety sensor exceeds 95 °C
Possible
cause
Action
1 Resistance in the installation is too high Check if not all (thermostatic) radiator valves are clogged
with dirt
2 Heating capacity is too large for the installation Adjust the heating capacity
3 Safety sensor is faulty 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)
4 Problem with the pump or pump cable (flex)
(no circulation)
Check if the pump cable (flex) is faulty or if the pump is
stuck
5 Water pressure is too low in the installation Top up the system
Code Meaning
4L Short circuit in safety sensor
Possible
cause
Action
1 Safety sensor is faulty 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)
2 A short or bad connection in the cable harness Check the cable harness and/or connector of the sensor
3 UBA might be faulty Check the UBA by temporarily connecting a different UBA
(see subsection 5.3.3)
Code Meaning
4P Safety sensor has a loose connection or is defective
Possible
cause
Action
1 Safety sensor faulty or disconnected 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)
2 A short or bad connection in the cable harness Check the cable harness and/or connector of the sensor
3 UBA might be faulty Check the UBA by temporarily connecting a different UBA
(see subsection 5.3.3)
Code Meaning
4U Short circuit in flow sensor
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 A short or bad connection in the cable harness Check the cable harness and/or connector of the sensor
3 UBA might be faulty Check the UBA by temporarily connecting a different UBA
(see subsection 5.3.3)