Baxi Potterton BBU 15 HE - Manual (Page 35)

12.0 Fault Finding
35
© Baxi Heating UK Ltd 2009
Refer to Section 16.0 “Illustrated Wiring Diagram” for position of terminals and components
Central Heating - Follow operational sequence
Turn on Power Supply
Display Illuminates
Error 20 or 28 flashing
Error 158 flashing
Burner lights
Error 110 flashing
Error 131 flashing
Turn Central Heating
thermostat to Maximum.
Pump runs
Fan runs
Spark at ignition electrodes for
up to 5 seconds and for 3
attempts
Error 155 flashing
Go to section ‘A’
Go to section ‘E’
Ensure all external controls
are calling for heat
Go to section ‘J’
Go to section ‘B’
Error 160 flashing
Go to section ‘D’
Error 133 flashing
Burner does not stay alights
after 5 seconds
Error 133 flashing
Go to section ‘H’
Operation sequence
successful
If the error 110 is still flashing.
Go to section ‘I’
Fan runs at correct speed
YES
YES
NO
NO
NO
YES
YES
YES
YES
YES
YES YES
YES
NO
YES YES
YES
YES
NO
NO
NO
NO
NO
Burner output modulates to
maintain the temperature set
Burner goes out
Go to section ‘C’
Ensure controls are set to
demand and verify the
contacts are closed
Error 160 flashing
Go to section ‘K’
YES
Go to section ‘G’
Turn the selector switch to
reset
Go to section ‘F’
YES
Check the Central Heating
NTC sensor
Go to section ‘E’
Fan stops after 10 seconds
Burner relights after at least 3
minutes, when the display is
less than the set temperature
(room thermostat open)
NO
NO
YES
NO
YES YES
Press the Service Reset
switch for 5 seconds
NO
Error 125 flashing
Ensure that the system is full,
primary circulation is OK &
that there is no blockage
YES
Go to section ‘J’
NOTE: Sections ‘A’ to ‘L’
referred to in the chart
opposite are on the
following pages