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SERVICE PRIMARY AND SECONDARY CHECK VALVE ASSEMBLIES
The Oxygen and Nitrous Oxide primary and secondary check valve assemblies may be field disassembled and replaced.
1) Primary Check Valve Assembly
O
2
A-2689-000
N
2
O A-2690-000
2) Cartridge Body
O
2
B-2237-000
N
2
O B-2275-000
3) 016 O’ Ring
PB-102-215
4) Secondary Check Valve Assembly
A-2693-000
5) Compression Spring
PB-115-63SS
SERVICE PRIMARY CHECK VALVE - SEE FIGURE 1
May be serviced with station pressurized to 50 PSI.
1. Remove front plate.
2. Unscrew the primary check valve assembly. Oxygen right hand threads; Nitrous Oxide left hand threads.
Note: the secondary check
valve will move into position and seal the 50 PSI of the station pressure as the primary check valve assembly is removed.
WARNING: Do not remove the cartridge body while servicing the primary check valve assembly. The secondary check
valve cannot seal the 50 PSI pressure if the cartridge body is removed.
3. Replace the entire assembly.
4. Screw the replaced assembly into the cartridge body.
5. Alignment & Adjustment for Front Cover Plate Installation — The Oxygen and Nitrous Oxide Valve Bodies are factory adjusted to allow for
the back of the Front Plate to press against the metal surfaces of both valve bodies. If adjustment is needed:
Rotate the Oxygen and Nitrous Oxide valve bodies so they both uniformly contact the back of the Front Plate when it is installed.
Oxygen has right hand threads and Nitrous Oxide has left hand threads.
6.
Leak test the entire system for working pressure leaks per the Monthly Check.
SERVICE SECONDARY CHECK VALVE - SEE FIGURE 2
WARNING: To service the secondary check valve, first turn off pressure. Do not remove the cartridge body until the pres-
sure is bled off. The secondary check valve cannot seal the 50 PSI pressure if the cartridge body is removed.
1.
Turn off pressure at tanks in tank room.
2. Follow procedure to remove primary check valve assembly.
3. Depress secondary check valve further into station block using a small probe or screw driver to bleed off pressure.
4. Unscrew cartridge body out of the station block.
5. Take a small screw driver or needle nose pliers and insert into holes at the center of secondary check valve. Carefully remove check
valve and spring.
6. Replace the 016 o-ring and secondary check valve parts as required and place in position for reassembly.
7. Screw in the cartridge body and tighten.
8. Screw in the primary check valve assembly and align and adjust for front plate installation.
9.
Leak test the entire system for working pressure leaks per the Monthly Check.
