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)