Danfoss E24

High

AK-CC 550A — S2 sensor error (coil outlet)

Danfoss E24: S2 sensor error (coil outlet) This fault noticeably affects operation.

Possible causes

Sensor S2 defective, cable break or short circuit
Loose/oxidized connector at the terminal block (terminals 35-40 area)

Check steps

Measure resistance/signal of S2 and compare against the sensor type's expected value
Check S2 wiring and terminal connection, replace sensor if needed

Affected parts

S2 sensor (coil outlet)
Sensor cable/connector

Safety note

De-energize before replacing the sensor.

Source: Danfoss resmi servis kilavuzu (bagimsiz cift-dogrulandi) — Danfoss AK-CC 550A Pocket Guide / Service Guide, doc AX278928624187en-000101 (2018.08), Alarm Codes table: "E24/--- S2 error" — "Error on S2 sensor". S2 is the Pt1000 (AKS11) sensor located at the evaporator/coil outlet (per Danfoss AK-CC550A/550B installation & user guides). Note: the phrase "Sensorfehler S2 (Ver…

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