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Error code reference
Denso Air Conditioner Error Code ALRM
Unit stop signal detected from fire alarm system: external fire alarm input signal is active.
SourceDENSO Office Pro 12 - Full Service Manualp. 33
Diagnostic procedure
The full ALRM procedure
Step 1 is visible so you can confirm you are on the right page. The remaining steps, the ones that tell you whether to actually replace a part, unlock with any pass.
MyPros+ · DiagnosticsStep 1 preview
1
First diagnostic step
After input signal turns off, reset the system by pressing ON/OFF and HI/LO buttons simultaneously for 5 sec.
SourceDENSO Office Pro 12 - Full Service Manualp. 33
More steps, wiring diagram references, and verified part numbers
Includes expected resistance and voltage values, connector pinouts, and supersession notes for replacement parts.
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Where this code is documented
4 manuals in the MyPros+ library document this code for Denso air conditioner.
Models covered by the manuals that document this code
75,000+ service documents · 20,000+ error codes · 100+ brands
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