12-6-3. Safety Device Operated
Failure Display on Outdoor Unit PCB: ● ● ● ●
Check safety device.
➀Disconnect safety device connector (CN12, 2P, WHT) from outdoor unit PCB, and measure resistance on the safety device.
Normal
1 Ω or less
* Use a circuit tester (set to Ω range).
In case of abnormality ➞ Replace temperature fuse or temperature limiting switch.
12-6-4. Erroneous Flame Detection
Failure Display on Outdoor Unit PCB: ● ● ● ●
Check flame sensor probe.
➀Measure voltage of alternative current between flame rod connector (1P, CN17) and ground.
Normal
AC 104 – 126 V
*Use a circuit tester (set to AC range).
In case of abnormality ➞ Replace outdoor unit PCB.
➁Remove flame rod connector, and measure direct current between connector and PCB.
Normal
DC 1µA or less
*Use a circuit tester (set to DC range).
In case of abnormality ➞ Replace outdoor PCB.
Caution: The flame rod retains electromotive force immediately after combustion ceases, therefore measure- ment should be made while the equipment is cool.
12-6-5. Ignition Failure
Failure Display on Outdoor Unit PCB: ● ● ● ●
1) Check ignition transformer.
➀Check if ignition wires are disconnected or have voltage leak.
➁Measure AC voltage between the connectors (CN07) to the ignition electrode.
Normal
AC 104 – 126 V
*Use a circuit tester (set to AC range).
In case of abnormality ➞ Replace outdoor unit PCB.
If voltage is normal but sparking noise cannot be heard, replace the ignition electrode. Caution: If the ignition wires are disconnected, connect them by pushing them in firmly.
2) Check gas valve (GV1).
➀Measure DC voltage at the connector (CN08) of electromagnetic valve (under heating operation, during com- bustion).
Normal
WHT – WHT DC 90 – 120 V
*Use a circuit tester (set to DC range).
In case of abnormality ➞ Replace outdoor unit PCB.
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