Service manual

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(2) Measure the current between flame rod (or Blue
1 of connector 78) and electrode.
Normal
DC 1µA or higher (during flame
detection)
Yes
Check for connection failure between
circuit board ground and metallic
section of unit, then check the gas
pressure and airflow (has the flame
been blown out by excessive airflow?).
No
Replace the flame rod.
If error display 29 appears,then check the drain trap
water level electrode.
(1) Measure the voltage between Blue 29 and
Green 32 of connector 38 on the circuit board.
11. Drain trap water level electrode error.
Yes Continue to (2).
If error display 12 or 72 appears, then check the
flame rod.
(1) Measure the frequency between the flame rod
and burner case (GUD) when the remote
controller is turned on.
10. Flame rod error.
Yes Continue to (2).
No Replace the circuit board.
Normal 10kHz - 100kHz
Normal
DC 4V or more
No
• Check the clogging of drain piping,
drain trap and connection hose.
• Replace the circuit board.