Loss of the Duct Temperature Sensor

TASK 21-26-00-810-828-A
Loss of the Duct Temperature Sensor

1. Possible Causes

CARTRIDGE-AVNCS VENT FILTER [2082HM]
SENSOR-DUCT TEMP, AVNCS VENT [26HQ]
AEVC [10HQ]
wiring

2. Job Set-up Information
A. Referenced Information

REFERENCE	DESIGNATION
AMM 21-26-00-710-001	Operational Check of the Avionics Equipment Ventilation-System via MCDU
AMM 21-26-00-710-002	Operational Check of Override Function (BLOWER and EXTRACT)
AMM 21-26-00-710-008	Operational Test to Read the CFDS for CLASS 3 Faults of the AEVC
AMM 21-26-00-710-009	Operational Test to Read the CFDS for LAST LEG REPORT of the AEVC
ASM 212603
AMM 21-26-12-000-001	Removal of the Avionics Ventilation Duct Temperature Sensor
AMM 21-26-12-400-001	Installation of the Avionics Ventilation Duct Temperature Sensor
AMM 21-26-34-000-001	Removal of the Avionics Equipment Ventilation Computer (AEVC)
AMM 21-26-34-400-001	Installation of the Avionics Equipment Ventilation Computer (AEVC)
AMM 21-26-43-920-001	Discard the Filter Cartridge (PALL)

3. Fault Confirmation
Subtask 21-26-00-865-069-A

A. Table of the circuit breakers used in this procedure:

PANEL	DESIGNATION	FIN	LOCATION
** ON A/C ALL
122VU	AIR COND/AVNCS/VENT/MONG	3HQ	Y17

Subtask 21-26-00-710-096-A

B. Test
(1) Do the reset of the AEVC (10HQ).
(a) Open the circuit breaker AIR COND/AVNCS/VENT/MONG (3HQ).
(b) Wait for five seconds.
(c) Close the circuit breaker AIR COND/AVNCS/VENT/MONG (3HQ).
(2) On the VENTILATION section of the overhead control and indicating panel 22VU, release the VENTILATION/BLOWER pushbutton switch (13HQ) (the OVRD legend comes on).
(3) Do the operational test of the avionics equipment ventilation from the Multipurpose Control and Display Unit (MCDU) AMM 21-26-00-710-001.
(4) Read the LAST LEG REPORT of the AEVC AMM 21-26-00-710-009.
(5) Read the CLASS 3 faults of the AEVC AMM 21-26-00-710-008.

4. Fault Isolation
Subtask 21-26-00-810-075-D

A. If the fault symptom is identified by the maintenance message DUCT TEMP SENSOR 26HQ and the upper ECAM DU warning VENT BLOWER FAULT:

Make sure that the avionics ventilation filter is not dirty.

(1) If the avionics ventilation filter is dirty:

Replace the CARTRIDGE-AVNCS VENT FILTER [2082HM] AMM 21-26-43-920-001.

(2) If the avionics ventilation filter is not dirty:

Replace the SENSOR-DUCT TEMP, AVNCS VENT [26HQ] AMM 21-26-12-000-001 and AMM 21-26-12-400-001.

(3) If the fault continues:

Replace the AEVC [10HQ] AMM 21-26-34-000-001 and AMM 21-26-34-400-001.

(4) If the fault continues:

Do a check and repair the wiring ASM 212603 between:
. Pin AB/4D of the AEVC (10HQ) and pin A/E of the avionics-ventilation duct-temperature sensor (26HQ)
. Pin AB/5D of the AEVC (10HQ) and pin A/C of the avionics-ventilation duct-temperature sensor (26HQ)
. Pin A/F of the avionics-ventilation duct-temperature sensor (26HQ) and the ground
. Pin A/B of the avionics-ventilation duct-temperature sensor (26HQ) and the ground
. Pin 2 of the AIR COND/AVNCS/VENT/MONG circuit breaker (3HQ) and pin A/A of the avionics-ventilation duct-temperature sensor (26HQ).

Subtask 21-26-00-710-097-A

B. Test
(1) On the VENTILATION section of the overhead control and indicating panel 22VU, push the VENTILATION/BLOWER pushbutton switch (13HQ) (the OVRD legend goes off).
(2) Do the operational test of the override function AMM 21-26-00-710-002 .

[Rev.8 from Aug 2018] 2026.04.04 04:24:38 UTC