Spirax Sarco LE33 Two-port Control Valve

1. Installation and commissioning

Installation

Install the valve in a horizontal pipeline with flow in the direction of the arrow cast on the body. Fit the valve into the pipeline in accordance with the applicable installation and maintenance instructions.

Always install a suitable strainer upstream of the control valve. On steam installations, install a separator upstream and provide a drain trap set where condensate can collect ahead of the valve.

Bypass arrangement

Isolation valves are recommended upstream and downstream of the control valve, together with a manual regulating valve in the bypass. The bypass valve can then control the process while the control valve is isolated for maintenance.

Commissioning

Commission the actuator in accordance with the Spirax Sarco installation, maintenance and operating instructions supplied for that actuator.

2. Maintenance

Routine maintenance

After 24 hours of operation

Check pipeline connections and flange-bolt tightness. Where high-temperature graphite stem seals are fitted, tighten the gland nut by approximately one quarter turn. Do not overtighten because excessive friction can restrict the stem.

Every three months

Visually inspect the seals for leakage and take corrective action where required. Replace worn PTFE chevron stem seals. For high-temperature graphite stem seals, tighten the gland by approximately one quarter turn without creating excessive stem friction. If adjustment cannot correct the leakage, replace the graphite packing.

Annually

Inspect the valve for wear or damage. Replace damaged stem and plug assemblies, seats and seals as necessary. High-temperature graphite packing is subject to normal operating wear and should be replaced during routine inspection to avoid premature seal failure.

Replacing PTFE chevron seals

1. Isolate the valve on both sides and confirm that trapped pressure has been safely relieved.

2. Remove the actuator in accordance with its instructions.

3. Undo the four bonnet nuts and remove the bonnet complete with stem and plug. Take care: pressurised fluid may remain trapped between the isolation valves.

4. Remove the locknut and gland. Withdraw the stem and plug, then discard the packing set and gland gasket.

5. Inspect all parts for damage or deterioration. Deposits or scoring on the stem will cause premature seal failure.

6. Clean the parts carefully without scratching the stem or gland bore. Refit the gland and stem.

7. Refit the bonnet with a new gasket, leaving the stem projecting. Fit the four nuts and tighten them to the table values while ensuring the plug is seated.

8. Fit the packing spring over the stem, renew the gland gasket, insert the new chevron seals without damaging their sealing lips, and fit a new guide.

9. Screw the gland down sufficiently to seat the gasket. Confirm that the stem moves freely, then refit the locknut.

10. Refit the actuator and mounting nut, connect the actuator to the stem, return the valve to service and check the packing for leakage.

Replacing graphite seals

1. Isolate the valve, safely relieve trapped pressure, remove the actuator and remove the bonnet assembly as described above.

2. Remove the locknut and gland, withdraw the stem and plug, and discard the old packing and gasket.

3. Inspect and clean all parts, renewing any damaged stem or plug components.

4. Install the lower support ring, graphite rings and upper support ring in their original sequence. Stagger adjacent ring joints by 90 degrees.

5. Insert the stem and plug carefully through the packing. Refit the bonnet with a new gasket, centre the plug in the seat and tighten the bonnet nuts to the specified torque.

6. Tighten the gland until it begins to compress the packing, then apply a further one and a half turns. Move the stem after each adjustment to bed the seals.

7. Refit the actuator and cycle the stem through its full travel at least five times. Apply the final gland adjustment specified by valve size, commission the actuator and check for leakage. Do not overtighten.

Replacing the plug and seat

1. Isolate the valve on both sides, safely relieve trapped pressure, remove the actuator and remove the bonnet assembly.

2. Remove the locknut, gland, packing and bonnet gasket. Clean the bonnet and fit the replacement stem and plug assembly.

3. Unscrew the seat using the special tool available from Spirax Sarco for the valve size and type. Remove and renew the seat gasket.

4. Apply a small amount of silicone grease to the new seat thread, screw it into the body and tighten it to the specified torque.

5. Refit the bonnet with a new gasket, centre the plug in the seat and tighten the four bonnet nuts to the specified torque.

6. Install new chevron or graphite packing as applicable, verify free stem movement, refit the actuator and return the valve to service. Check the packing for leakage.

3. Technical details

LE33 weights

Materials

Recommended tightening torques

4. Spare parts and ordering identification

When ordering spare parts, quote the product code shown on the body label and use the documented spare-part description. Available assemblies include the actuator mounting nut, packing sets, stem and plug assembly, seat and gaskets, bonnet-gasket packs and graphite packing sets.

The source ordering example identifies LE33 as an L-series, two-port, equal-percentage valve with cast-iron body and flanged connection. The exact Kv, pressure class, stem-seal option and body-label code must be taken from the installed valve or confirmed with Spirax Sarco; they must not be inferred from the model alone.