Functional Test of the Positive and Negative Delta P Protection of the Safety Valves

TASK 21-31-00-720-001-A
Functional Test of the Positive and Negative Delta P Protection of the Safety Valves

NOTE: If the test set NORD MICRO PN 0622-19857-01 is not available the test set NORD MICRO PN 0622-19857-02 can be used and vise versa. If either one of the test sets is not available send the safety valves in shop for functional test.

ZONE: 260

1. Reason for the Job
Refer to the MPD TASK: 213100-05
FUNCTIONAL CHECK OF POSITIVE/NEGATIVE DELTA "P" PROTECTION OF THE SAFETY VALVES.

2. Job Set-up Information
A. Fixtures, Tools, Test and Support Equipment

REFERENCE	QTY	DESIGNATION
No specific	1	ACCESS PLATFORM 4M (13 FT)-ADJUSTABLE
No specific	AR	AIR SOURCE 0.02 BAR (0.3 PSI)
No specific	AR	AIR SOURCE 1.7 TO 2 BAR (25 TO 30 PSI) - FILTERED, DRY
No specific	AR	SAFETY CLIP - CIRCUIT BREAKER
No specific	AR	TEST UNIT - VALVE ACTUATING (0622-19857-01 TYPE)
0622-19857-02	1	TEST SET - VALVE ACTUATING

B. Work Zones and Access Panels

ZONE/ACCESS	ZONE DESCRIPTION
260	AFT CABIN UTILITY AREA
312AR

C. Referenced Information

REFERENCE	DESIGNATION
TASK 21-31-00-710-006-A	Operational Test of Safety Valve Position Indication
TASK 24-41-00-861-002-A	Energize the Aircraft Electrical Circuits from the External Power
TASK 24-41-00-861-002-A-01	Energize the Aircraft Electrical Circuits from the APU
TASK 24-41-00-861-002-A-02	Energize the Aircraft Electrical Circuits from Engine 1(2)
TASK 24-41-00-862-002-A	De-energize the Aircraft Electrical Circuits Supplied from the External Power
TASK 24-41-00-862-002-A-01	De-energize the Aircraft Electrical Circuits Supplied from the APU
TASK 24-41-00-862-002-A-02	De-energize the Aircraft Electrical Circuits Supplied from the Engine 1(2)
Safety Valve - Differential Pressure Test

3. Job Set-up
Subtask 21-31-00-861-060-A

A. Energize the aircraft electrical circuits
(Ref. AMM TASK 24-41-00-861-002).

Subtask 21-31-00-010-054-A

B. Get Access
(1) Put the ACCESS PLATFORM 4M (13 FT)-ADJUSTABLE in position at the access panel 312AR.
(2) Remove the access panel 312AR.
(3) In the cabin remove the food trolleys (1) and the access panel (5).

Subtask 21-31-00-865-060-A

C. Open, safety and tag this(these) circuit breaker(s):

PANEL	DESIGNATION	FIN	LOCATION
** ON A/C ALL
49VU	AIR COND/CAB/PRESS/CTL1	1HL	D09
122VU	AIR COND/CAB PRESS/CTL/MAN	3HL	Y23
122VU	AIR COND/CAB PRESS/CTL/2	2HL	Y22

4. Procedure
Subtask 21-31-00-480-053-A

A. Functional Test of the Safety Valve
(1) Installation of the Test Equipment 0622-19857-02 TEST SET - VALVE ACTUATING TEST UNIT - VALVE ACTUATING (0622-19857-01 TYPE).

Safety Valve - Differential Pressure Test

(a) On the Test Set
1 Make sure that the pressure controller (18) and the vacuum controller (25) are fully closed.
2 Connect these items:

The pressure input (19) to a constant positive pressure supply AIR SOURCE 1.7 TO 2 BAR (25 TO 30 PSI) - FILTERED, DRY.
The vacuum input (24) to a constant negative pressure/vacuum supply AIR SOURCE 0.02 BAR (0.3 PSI).
The electrical-power connector (26) to a 28V DC power supply.
The test wiring to the safety-valve position-switch connector (27).
The connector with the orange color of the flexible hose assembly (29) to the vacuum output connector (23).
The connector with the green color of the flexible hose assembly (29) to the pressure sense connector (21).
The connector with the green color of the flexible hose (17) to the pressure output connector (20).

3 On the check device (15) make sure that the fixed pressure connector (16) is screwed out.
(b) On the Aircraft:
1 Connect the test wiring to the safety valve electrical-connector (3).
2 Remove the nut (33), the strainer (34) and the washer (35).
3 Put the check device (15) in position on the bellmouth (14) and close the clamps (32).
4 Make sure that the pivoted pressure connector (30) is in position over the poppet valve outlet (37).

NOTE: You can see this through the cut-outs in the check device (15).

5 Screw in the fixed pressure connector (16) until you get a seal at the poppet valve (12), and the clamps (32) are tight.
6 Adjust the pivoted pressure connector (30) with the adjustment screw (31) until you get a seal at the poppet valve outlet (37).
7 Connect these items:

The connectors with the green color of the flexible hose (17) and the flexible hose assembly (29) to the fixed pressure connector (16).
The connector with the orange color of the flexible hose assembly (29) to the pivoted pressure connector (30).
The neutral colored connector of the flexible hose assembly (29) to the bulkhead connector (36).

(2) Functional Test of the Test Equipment
(a) Apply hand pressure at points A to open the safety valve (4).

The position indicator lamp (22) on the test set comes on.

(b) Allow the safety valve (4) to close.

The position indicator lamp (22) on the test set goes off.

(c) For PN 0622-19857-01
Adjust the pressure monitor to zero:
1 Turn the adjustment screw (28) until the value shown on the pressure monitor is zero.
(d) For PN 0622-19857-02 (Druck display)
Adjust the pressure monitor to zero:
1 Press F1 and F2 keys at the same time to enter the function.
2 Use the keys AL1 and AL2 to set the zero value.
3 Press F2 key.
4 Press F2 key again to return the display to normal operation.
(e) For PN 0622-19857-02 (red lion display)
Adjust the pressure monitor to zero:
1 Disconnect the green connector of the flexible hose assembly (29) from the pressure sense connector (21).
2 Connect a pneumatic connector to the pressure sense connector (21).

NOTE: The other side of the pneumatic connector is open to the ambient air.

3 Make sure that the electrical-power input connector (26) is connected to the 28V DC POWER SUPPLY UNIT.
4 On the pressure monitor, push the RST button.
5 Make sure that the pressure value shown on the pressure monitor is 0.0000.
6 Disconnect the pneumatic connector from the pressure sense connector (21).
7 Connect the green connector of the flexible hose assembly (29) to the pressure sense connector (21).
(f) Slowly open the vacuum control (25) until you get a stable pressure value shown on the pressure monitor.

NOTE: Do not go above 588 mbar (8.53 psi) pressure.
Failure to get a stable pressure value is an indication of possible leaks.
Check the seal at the poppet valve (12) and at the poppet valve outlet (37).

(g) Close the vacuum control (25).
(h) Disconnect the connector with the orange color at the vacuum outlet (23) to release any pressure in the system.
(i) Reconnect the connector with the orange color to the vacuum outlet (23).

Subtask 21-31-00-720-051-A

B. Functional Test of the Safety Valve

Safety Valve - Differential Pressure Test

(1) Testing of the Safety Valve
(a) Functional Test of the Positive Differential-Pressure Protection
1 Make sure that the value shown on the pressure monitor is set at zero.

NOTE: For adjustment to zero value refer to working step A2c or A2d.

2 Slowly open the vacuum control (25) to apply vacuum.
3 Increase the vacuum until the safety valve opens.

NOTE: You know this when the position indicator lamp (22) comes on.

4 When the position indicator lamp (22) comes on, you must make a note of the value shown on the pressure monitor.
This value must be between 586 mbar (8.50 psi) and 600 mbar (8.70 psi) pressure.
5 Close the vacuum control.
6 Release the vacuum.

NOTE: To do this you must disconnect the connector with the orange color at the vacuum output (23).

7 Reconnect the connector with the orange color to the vacuum output (23).
8 Do the test with the calibrated safety valve at least 2 times more to make sure the set point adjustment is the same each time.
(b) Functional Test of the Negative Differential-Pressure Protection
1 Make sure that the value shown on the pressure monitor is set at zero.

NOTE: For adjustment to zero value refer to working step A2c or A2d.

2 Slowly open the pressure control (18) to give a positive pressure.
3 Increase the positive pressure until the safety valve opens.

NOTE: You know this when the position indicator lamp (22) comes on.

4 When the position indicator lamp (22) comes on you must make a note of the value shown on the pressure monitor.
This value must be between 5 mbar (0.07 psi) and 18.0 mbar (0.26 psi).
5 Close the pressure control (18).
6 Release the positive pressure.

NOTE: To do this you must disconnect the connector with the green color at the pressure output (20).

7 Do the negative relief set point check at least 2 times more to make sure the safety valve function is correct.

Subtask 21-31-00-080-053-A

C. Removal of the Test Equipment

Safety Valve - Differential Pressure Test

(1) On the Aircraft
(a) Disconnect these items:

The connectors with the green color the flexible hose (17) and the flexible hose assembly (29) from the fixed pressure connector (16).
The connector with the orange color of the flexible hose assembly (29) from the pivoted pressure connector (30).
The neutral colored connector of the flexible hose assembly (29) from the bulkhead connector (36).

(b) Loosen the screw (31) and disengage the pivoted pressure connector from the poppet valve outlet (37).
(c) Screw out the fixed pressure connector (16) to disengage it from the poppet valve (12).
(d) Release the clamps (32) and remove the check device (15) from the bellmouth (14).
(e) Disconnect the test wiring from the electrical connector (3).
(f) Remove the check device (15) and the test wiring from the aircraft.
(2) On the Test Set:
(a) Disconnect these items:

The connector with the green color of the flexible hose (17) from the pressure output connector (20).
The connector with the green color of the flexible hose assembly (29) from the pressure sense connector (21).
The connector with the orange color of the flexible hose assembly (29) from the vacuum output connector (23)
The test wiring from the safety-valve position-switch connector (27).
The electrical power connector (26).
The pressure input (19) and the vacuum input (24).

Subtask 21-31-00-420-051-A

D. Aircraft Maintenance Configuration
(1) Install the washer (35), the strainer (34) and the nut (33).
(2) Remove the blanking caps from the disconnected electrical connectors.
(3) Make sure that all the electrical connections are clean and in the correct condition.
(4) Connect the electrical connector (2).

Subtask 21-31-00-865-061-A

E. Remove the safety clip(s) and the tag(s) and close this(these) circuit breaker(s):

PANEL	DESIGNATION	FIN	LOCATION
** ON A/C ALL
49VU	AIR COND/CAB/PRESS/CTL1	1HL	D09
122VU	AIR COND/CAB PRESS/CTL/MAN	3HL	Y23
122VU	AIR COND/CAB PRESS/CTL/2	2HL	Y22

Subtask 21-31-00-710-061-A

F. Do the operational test of the safety valves and position indication (Ref. AMM TASK 21-31-00-710-006).

5. Close-up
Subtask 21-31-00-410-053-A

A. Close Access
(1) Make sure that the work area is clean and clear of tools and other items.
(2) Install the access panel (5) and the food trolleys (1).
(3) Install the access panel 312AR.
(4) Remove the access platform(s).

Subtask 21-31-00-862-059-A

B. De-energize the aircraft electrical circuits
(Ref. AMM TASK 24-41-00-862-002).

[Rev.10 from 2021] 2026.04.02 06:11:14 UTC