Baxi Potterton BBU 15 HE Go to section ‘A’, Display Illuminates, Error 110 flashing, Pump runs

12.0 Fault Finding

Refer to Section 16.0 “Illustrated Wiring Diagram” for position of terminals and components

Central Heating - Follow operational sequence

Turn on Power Supply	NO
		Go to section ‘A’
Display Illuminates
YES

NOTE: Sections ‘A’ to ‘L’ referred to in the chart opposite are on the following pages

Error 110 flashing	YES
Error 131 flashing
NO
	YES
Error 20 or 28 flashing
NO
	YES
Error 158 flashing
NO
Turn Central Heating	NO
thermostat to Maximum.
Pump runs
YES
	YES
Error 155 flashing
NO
	YES
Error 125 flashing
NO
	NO
Fan runs
YES	NO
Fan runs at correct speed
YES
Spark at ignition electrodes for	NO
up to 5 seconds and for 3
attempts

YES

NO

YES

Burner lights

Press the Service Reset	YES
switch for 5 seconds
Go to section ‘E’
Go to section ‘C’
NO
Ensure all external controls	YES
are calling for heat
Go to section ‘J’
Ensure that the system is full,
primary circulation is OK &
that there is no blockage
Error 160 flashing
Go to section ‘D’
Error 160 flashing
Go to section ‘K’
	YES
Error 133 flashing
Go to section ‘F’
	YES
Burner does not stay alights
after 5 seconds

If the error 110 is still flashing.

Go to section ‘I’

Ensure controls are set to

demand and verify the

contacts are closed

Go to section ‘B’

Go to section ‘J’

Go to section ‘G’

Turn the selector switch to

reset

Error 133 flashing

Go to section ‘H’

YES

Burner output modulates to maintain the temperature set

YES

Burner goes out

NO

YES

Check the Central Heating

NTC sensor

Go to section ‘E’

Fan stops after 10 seconds

YES

Burner relights after at least 3 minutes, when the display is less than the set temperature (room thermostat open)

YES

Operation sequence

successful

© Baxi Heating UK Ltd 2009 35