SMAR HART FY500, Installation Operation & Maintenance

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Section 6 - Maintenance
6.9
Pressure Regulator
To disassemble the Pressure Regulator, perform the following steps, refer to Figure 6.5 .
1. Using a flat screwdriver, remove the regulator cover.
2. Remove the regulator spring button and the regulator spring.
3. Remove the regulator plug and its o-ring.
4. Using a flat screwdriver, remove the poppet guide, its O-ring, the regulator poppet, and the
regulator spring.
5. The regulator cavity can be cleaned with a non-residue cleaner, lint free cloth and soft bristle
brush.
To assemble the Pressure Regulator, perform the following steps, refer to Figure 6.5.
1. Place the regulator spring and regulator poppet into the housing cavity.
2. Place the poppet guide O-ring on the poppet guide and insert the regulator poppet through the
bottom of the poppet guide. Screw the poppet guide into the housing being careful not to over
tighten. A maximum torque of 4 to 5 inch-pounds is sufficient. Make sure the poppet is free to
move up and down and has spring load.
3. Being careful to push the O-ring into the bore.
4. Place the regulator plug into the bore.
5. Place the regulator spring on the regulator plug, and then place the regulator spring button on
the spring.
6. Place a small amount of thread locking compound on the regulator cover and screw into the
housing.
7. Position the regulator cover leaving approximately 2 mm of the pneumatic housing surface.
Spool Valve
The spool valve will apport supply to the actuator. An increase in the loop control signal causes the
pneumatic signal increase, pushing the spool and, by means of the pneumatic signal, change the
output pressures and flow rate. This will cause the actuator stem movement.
WARNING
Never use oil or lubricant on the spool valve, otherwise the positioner performance will
be impaired
.
To check the Spool Valve, perform the following steps, refer to Figure 6.5.
1. Remove the spool valve and its spring.
2. Check for scratches, contamination, or dirty air supply. To operate properly, the spool should
slide freely and fall through by its own weight when held vertically.
3. The valve spool and the spool cavity can be cleaned with a non-residue cleaner, lint free cloth
and soft bristle brush. Blow out all pneumatic connections to prevent dirt, chips, or debris from
entering the housing.
4. Place the spool spring and the spool valve into the housing. Do not use any oil or lubricant.
Vent Cover
The Vent Cover incorporates a filter element in a two-piece cover. This protects the spool valve
chamber from moisture and provides protection against exhaust air from the spool valve.
To check the Vent Cover, perform the following steps, refer to Figure 6.5.
4. Remove the vent cover.
5. Check for contamination or dirty air supply. Replace it if necessary.
6. Reinstall the vent cover.