Boulter Buderus Benchmark 600-28C Installation And Servicing Instruction page 40

5 Servicing
Code Meaning
3Y Blinking fault code: Fan running too fast
Possible
cause
1 Fan wiring or connections faulty action
2 Power supply may be faulty
3 Flue gas system may be dirty
4 Problem with the fan, heat exchanger, burner
Code Meaning
4A Blinking fault code: Flow sensor exceeds 105 °C
Possible
cause
1 Resistance in the installation is too high
2 Water pressure is too low in the installation
3 Problem with the pump or pump cabling
(no circulation)
4 Bi-sensor is dirty or faulty
Code Meaning
4E Blinking fault code: Bi-sensor not working
Possible
cause
1 Bi-sensor is faulty
Code Meaning
4F Blinking fault code: Flow sensor exceeds 100 °C
Possible
cause
1 Resistance in the installation is too high
2 Water pressure is too low in the installation
3 Problem with the pump or pump cabling
(no circulation)
4 Bi-sensor is dirty or faulty
Subject to modifications resulting from technical improvements!
40 Installation and maintenance instructions for wall-mounted condensing gas boiler 600 - 28C • 01/2004
Action
Check the fan wiring and connections
(see subsection 5.3.3)
Check power supply
Check the flue gas system (see subsection 5.3.1)
Check the fan, heat exchanger and burner for dirt
Action
Check if not all (thermostatic) radiator valves are closed or
clogged with dirt
Top up the system (see subsection 2.1.1)
Check if the pump cabling is faulty or if the pump is stuck.
Replace pump when necessary (see subsection 5.3.6 and
subsection 5.3.7)
Check the bi-sensor for dirt. Measure if resistance over the
sensor is correct. If not replace bi-sensor (see subsection
5.3.8, subsection 5.3.9, subsection 5.3.10)
Action
Replace bi-sensor (see subsection 5.3.9)
Action
Check if not all (thermostatic) radiator valves are closed or
clogged with dirt
Top up the system (see subsection 2.1.1)
Check if the pump cabling is faulty or if the pump is stuck.
Replace pump when necessary (see subsection 5.3.6 and
subsection 5.3.7)
Check the bi-sensor for dirt. Measure if resistance over the
sensor is correct. If not replace bi-sensor (see subsection
5.3.8, subsection 5.3.9, subsection 5.3.10)
Boulter Buderus Ltd. • http://www.boulter-boilers.com