Unwanted Warning of the Duct Temperature Sensor

TASK 21-26-00-810-817-A
Unwanted Warning of the Duct Temperature Sensor

1. Possible Causes

CARTRIDGE-AVNCS VENT FILTER [2082HM]
CHECK VALVE-AIR INLET, AVNCS VENT [2150HM]
PRESS SW-BLOWER FAN, AVNCS VENT [17HQ]
PRESS SW-BLOWER FAN, AVNCS VENT [19HQ]
SENSOR-DUCT TEMP, AVNCS VENT [26HQ]
FAN-BLOWER, AVNCS VENT [20HQ]
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 21-26-00-710-008	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 21-26-11-000-001	Removal of the Blower and Extract Fan Pressure Switches
AMM 21-26-11-400-001	Installation of the Blower and Extract Fan Pressure Switches
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 21-26-43-920-001	Discard the Filter Cartridge (PALL)
AMM 21-26-51-000-001	Removal of the Extract and Blower Fans
AMM 21-26-51-400-001	Installation of the Extract and Blower Fans
AMM 21-26-56-000-001	Removal of the Air Inlet Check Valve
AMM 21-26-56-280-002	Operational Check of Air Inlet Check Valve
AMM 21-26-56-400-001	Installation of the Air Inlet Check Valve

3. Fault Confirmation
Subtask 21-26-00-865-080-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 21-26-00-710-060-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) Do the operational test of the avionics equipment ventilation from the Multipurpose Control and Display Unit (MCDU) AMM 21-26-00-710-001.
(3) Read the LAST LEG REPORT of the AEVC AMM 21-26-00-710-009.
(4) Read the CLASS 3 faults of the AEVC AMM 21-26-00-710-008.

4. Fault Isolation
Subtask 21-26-00-810-055-D

A. If the fault symptom is identified by the upper ECAM DU warning VENT BLOWER FAULT and if the result of the operational test gives the "TEST OK" message:

Make sure that the avionics ventilation filter 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 filters is not dirty:

Do the operational check of the air inlet check-valve (2150HM) AMM 21-26-56-280-002.

(a) If the result of the operational check is not correct:

Replace the CHECK VALVE-AIR INLET, AVNCS VENT [2150HM] AMM 21-26-56-000-001 and AMM 21-26-56-400-001.

(b) If the result of the operational check is correct:

Replace the PRESS SW-BLOWER FAN, AVNCS VENT [17HQ] AMM 21-26-11-000-001 and AMM 21-26-11-400-001.

1 If the fault continues:

Replace the PRESS SW-BLOWER FAN, AVNCS VENT [19HQ] AMM 21-26-11-000-001 and AMM 21-26-11-400-001.

2 If the fault continues:

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 FAN-BLOWER, AVNCS VENT [20HQ] AMM 21-26-51-000-001 and AMM 21-26-51-400-001.

4 If the fault continues:

Continue with the subsequent step.

(3) Do a check of the wiring ASM 212603 between:

The AEVC (10HQ) and the blower fan pressure-switch (17HQ), pin AB/8C and pin A/A
The blower fan pressure-switch (17HQ), pin A/C and the ground
The AEVC (10HQ) and blower fan pressure-switch (19HQ), pin AB/8D and pin A/A
The blower fan pressure-switch (19HQ), pin A/C and the ground
The SDAC-1 (1WV1), SDAC-2 (1WV2) and the blower fan pressure-switch (17HQ), pin AD/9F and pin A/A (through the diode module 1800VD)
The SDAC-1 (1WV1), SDAC-2 (1WV2) and the blower fan pressure-switch (19HQ), pin AD/9F and pin A/A (through the diode module 1800VD).

(a) If the wiring is not correct:

Repair the related wiring .

(b) If the wiring is correct:

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)
. The SDAC-1 (1WV1), SDAC-2 (1WV2) and the avionics-ventilation duct-temperature sensor (26HQ), pin AD/9F and pin A/C (through the diode module 1800VD).

Subtask 21-26-00-710-061-A

B. Do the operational test given in Para. 3.

[Rev.8 from Aug 2018] 2026.04.04 04:24:37 UTC