Baxi Potterton BBU 15 HE - Manual (Page 36)

12.0 Fault Finding
36
© Baxi Heating UK Ltd 2009
Fault Finding Solutions Sections
Is there 230V at:
Check all system wiring and pump
Main terminals L and N Check electrical supply 1.
NO
Main terminal fuse Replace fuse
Replace PCB
Display
illuminated
2.
NO
PCB - X1 connector
terminals 1,2
Check wiring 3.
NO
NO
A
B
1.
2.
C
NO
YES
Fan connections correct at fan. PCB -
X2 connector, is 230V AC across
terminals 5 & 7
Fan jammed or faulty winding
Replace PCB
Replace fan
YES
D
E20 - Temperature sensor faulty.
Cold resistance approximately
10kΩ @ 25° C
(resistance reduces with increase in temp.)
E28 - Incorrect PCB fitted
NO
E
Replace sensor or PCB (E28)
Gas at burner Ensure gas is on and purged Replace PCB
Replace gas valve
PCB - X3 connector is 230V AC across
terminals 1 & 2
YES
NO
NO
F
Check and correct the connection of the
tube between the venturi and gas valve
1.
2.
Service Reset
Condensate Pump does not run On Reset is there 230V at:
PCB - X3 connector terminals 5 &
6 for at least 2 seconds
Replace PCB
NO
Condensate Pump terminals for at
least 2 seconds
Replace wiring
NO
YES
Replace Cond. Pump
Condensate Pump runs
YES
Condensate drain system blocked
Replace Float Switch
Clean condensate drain system
Replace PCB
G
Check and correct if necessary
1. Ignition electrode and lead
2. Electrode connection
3. Spark gap and position
voltage at PCB - X2 connector is
110V AC across terminals 2 & 5
(Note: from multimeter connect
‘common’ to 2 & ‘volts’ to 5)
Check wiring
YES
NO
Replace igniter
YES
NO
YES