A.O. Smith TWI 35-200, Installation, User And Service Manual

Page: 78 / 92

Code and
description Cause Measure
XB2-XXXX
(lock out error)
Ignition error
Three unsuccessful
ignition attempts.
No gas - Make sure that the main gas supply
valve is open. If necessary, open the
valve.
- Make sure that the manual gas supply
valve, before the gas control valve, is
open. If necessary, open the valve.
- Make sure that the gas supply
pressure to the gas control valve is
correct, refer to Gas supply pressure.
Air in the gas pipes. - Bleed the air out of the gas pipe.
- Make sure that the gas supply
pressure to the gas control valve is
correct, refer to Gas supply pressure.
Defect in the spark igniter circuit. - Make sure that the spark igniter is
installed correctly.
- Make sure that the wiring of the spark
igniter is not damaged.
If necessary, replace the spark igniter.
Defect in the ionisation circuit. - Make sure that the flame probe is
installed correctly.
- Make sure that the wiring of the flame
probe is not damaged.
- Measure the ionisation current. This
current must be a minimum of 60 μA.
If necessary, replace the wiring and/or
flame probe.
Supply voltage too low. - Make sure that the supply voltage on
the controller is correct.
- If the supply voltage is below the
stated tolerance and the error
persists, contact your maintenance
and service engineer.
Bent flame probe is in contact with
metal surface. - Make sure that the flame probe is not
bend.
- If necessary, replace flame probe.
Ceramic part, of the flame probe, is
broken or cracked. - Make sure that the ceramic part of the
flame probe is not broken or cracked
in the vicinity of the burner.
- If necessary, replace flame probe.
XAF-XXXX
(lock out error)
Control error
Hardware failure
Too many resets. Turn off the power for 10 seconds.
XC9-XXXX
(lock out error)
Control error
Hardware failure
Disconnect the selection key. - Make sure that the selection is
connected to J12.
- If necessary, replace the selection key.
78 Installation, Maintenance and Service part