# SDR ASAA2021022334181

- Type: Service difficulty report (as reported; unverified)
- Difficulty date: February 23, 2021
- Submitted: February 26, 2021
- Operation: Air carrier
- Aircraft: [N537AS](https://openairdocs.org/aircraft/N537AS), registered now
- Make and model: Boeing 737890
- Aircraft serial: 35204
- Aircraft time: 34,205 hours, 9,950 cycles
- System (JASC): [2160 · Cabin Temperature Control System](https://openairdocs.org/jasc/2160)
- Part: Modulating Valve
- Part number: 3989083
- Part serial: 16689
- Condition: Faulted
- Location: Rt Ecs Sys
- Part time: 34,205 hours, 9,950 cycles
- Stage of operation: NR
- How discovered: O
- Nature of condition: J
- Precautionary procedure: O
- FAA source: FAA Service Difficulty Reporting System (https://sdrs.faa.gov/)
- Page: https://openairdocs.org/sdr/ASAA2021022334181

## Discrepancy

CONT CAB ZONE TEMP ANNUNCIATOR ILLUMINATED ON RECALL. EXTINGUISHES WHEN RESET.   GROUNDED - YES.  ACCOMPLISHED PACK/ZONE TEMP CONTROLLER BITE EST REF B737-800 AMM 21-61-00, SHOWS HARD FAIL "ZONE TRIM VALVE" ON NR 1 CONTROLLER.  ACCOMPLISHED B737-800 FIM 21-62 TASK 835 AFT CABIN TRIM AIR VALVE FAULT ISOLATION.  REMOVED AND REPLACED AFT CABIN TAV V145 REF AMM 21-61-21, OPS CHECK AND LEAK CHECK GOOD.

---
OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. Source documents are U.S. government works in the public domain.