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17

Error 17 — 4-way valve converse abnormal

Lennox · EL18KSLV Series Outdoor Units

What does 17 mean?

The 4-way valve is not functioning correctly to direct hot gas to the proper coil. This affects heating and cooling operation.

Common Causes

  • Faulty 4-way valve
  • Wiring issue to the 4-way valve
  • Control board issue

Repair Steps & Checklist

Click steps to track your progress.

  1. 1

    Refer to the 4-way valve testing procedure in the manual.

  2. 2

    Check the wiring connections to the 4-way valve.

  3. 3

    Ensure the control board is sending the correct signals.

Browse all codes in this manual (43)
Verified technical data. Last updated: April 2026

Related Faults

1Error 1 — EEPROM malfunction or damage10Error 10 — Outdoor defrost sensor failure11Error 11 — Suction temperature sensor failure
Source: Lennox EL18KSLV Series Outdoor Units
Open Manual (Page 70)Search more codes in this manual