A.O. Smith Innovo 12-160 Installation, Service & Maintenance Manual page 77

Code and description
F04 (lock out error)
Ignition error
Three unsuccessful
ignition attempts.
0312266_INNOVO_UKUK_V3.0, 2017-02-10
Cause
No gas.
Air in the gas pipes.
Defect in the hot surface igniter circuit.
Defect in the ionisation circuit.
Supply voltage too low.
Bent flame probe is in contact with
metal surface.
Ceramic part, of the flame probe, is
broken or cracked.
Measure
• 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 (see section
8.9.3).
• 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 (see section
8.9.3).
• Make sure that the hot surface igniter is
installed correctly.
• Make sure that the wiring of the hot
surface igniter is not damaged.
• Measure the resistance across the hot
surface igniter. This must be between the
36 and 72 Ohm (at room temperature).
• Make sure that the hot surface igniter
lights up during ignition.
If necessary, replace the hot surface igniter.
• 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 3 μA
(parameter 109).
If necessary, replace the wiring and/or
flame probe.
Make sure that the measured voltage is
230 V (-15%, +10%).
AC
• Make sure that the flame probe is not
bend.
• If necessary, replace flame probe.
• 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.
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