The TLV LEX3N-TZ inline repairable temperature control steam trap features a built-in scale removal function suitable for the accurate control of condensate discharge temperatures. It is designed for applications with operating pressures up to 4.6 MPaG (650 psig). Note that the LEX3N-TZ can only control the temperature of condensate discharge from the trap; it cannot control product temperature nor the temperature of condensate backing up in the system.

Safety Considerations

WARNING

Install properly and DO NOT use this product outside the recommended operating pressure, temperature, and other specification ranges. Improper use may result in such hazards as damage to the product or malfunctions, which may lead to serious accidents.

WARNING

Take measures to prevent people from coming into direct contact with product outlets. Always wear heat-insulated gloves when handling products with high body temperatures.

WARNING

When disassembling or removing the product, wait until the internal pressure equals atmospheric pressure and the surface of the product has cooled to room temperature.

Configuration

No.	Description	No.	Description
1	Body	12	Spring Pin
2	Cover	13	Seal Ring
3	Valve Stem	14	Screen
4	Adjusting Screw	15	Locknut
5	Bimetal Element	16	Cap Nut
6	Washer	17	Cover Gasket
7	Valve Seat	18	Nameplate
11	Snap Ring	21	Cap Nut Gasket

Exploded View

Specifications

INFO

Maximum allowable pressure (PMA) and maximum allowable temperature (TMA) are PRESSURE SHELL DESIGN CONDITIONS, NOT OPERATING CONDITIONS.

Applications

• DO NOT USE on any application except steam tracing lines, storage tank coils, instrument enclosures, steam trap air venting, and freeze protection of condensate lines.
• SUITABLE for steam tracing lines or storage tank coils ONLY IF the required product viscosity will be maintained when the condensate is sub-cooled at least 15 °C (27 °F), even to the point of the condensate having a lower temperature than the product temperature.
• SUITABLE for use on instrument enclosures ONLY IF the steam or condensate temperature in the enclosures will NOT damage the instrument.
• SUITABLE for use as an external air vent for TLV steam traps, or as a non-freeze valve for freeze protection of condensate lines.

Proper Installation

1. Before installation, be sure to remove all protective seals.
2. Blow out the inlet piping to remove any piping scraps, dirt and oil. Close the inlet valve after blowdown.
3. Verify that piping is of a suitable diameter.
4. Install in a place where caution plates can clearly be seen, in the lowest part of the pipeline so that condensate flows into the trap by gravity.
5. Install the product so that the arrow on the body is pointing in the direction of condensate flow.
6. The product may be installed either horizontally or vertically. When installing horizontally, make sure the product is installed with the temperature adjusting screw positioned higher than the piping. (Upside-down installation is not permissible.)
7. When used as an automatic non-freeze valve, do not use thin-walled tubing for outlet piping. Use a short, thick-walled pipe to discharge to atmosphere.
8. When used as an external air vent for TLV steam traps, connect to the top of the steam trap.
9. Install inlet and outlet valves to isolate the product in event of trap failure or maintenance.
10. If the product is subject to back pressure, install a check valve.
11. Open the inlet valve gradually and check to make sure that the product functions properly.

Operational Check

Status	Visual Symptoms
Normal	Condensate is being discharged from the discharge outlet. (The surface temperature of the trap should be about 10 to 20 °C lower than the set temperature.)
Blocked	No condensate is discharged and the surface temperature of the trap is low.
Blowing	Live steam continually flows from the outlet and there is a continuous hissing sound of flow. The surface temperature of the trap is higher than the set temperature.

Adjusting Temperature Setting

WARNING

To prevent possible injury, always relieve pressure from trap before opening to adjust the temperature setting. Always wear heat-insulated gloves and eye protection.

1. Close the inlet isolation valve, followed by the outlet isolation valve. Wait until the pressure equals atmospheric pressure and the trap body temperature cools to room temperature.
2. Hold the cover with one wrench and use another wrench to slowly loosen and remove the cap nut to allow any residual pressurized steam to leak.
3. Hold the adjusting screw in place with a flat-head screwdriver and remove the locknut slowly.
4. Use a flat-head screwdriver to turn the adjusting screw to adjust temperature. To raise the temperature setting, turn the adjusting screw counterclockwise. To lower the temperature setting, turn the adjusting screw clockwise.
5. Replace the locknut and tighten securely while holding the adjusting screw.
6. Replace the cap nut and tighten it to the proper torque (35 N·m).
7. Fully open the outlet isolation valve, then slowly open the inlet isolation valve and check for steam leaks.

Standard Factory Setting ("0" Position)

The standard "0" position is where the bottom of the adjusting screw slot is even with the top surface of the cap.

Set Temperature Adjustment Chart

The trap can be set to open at any temperature between 50 °C and 200 °C provided the set temperature is at least 15 °C below saturated steam temperature.

Cleaning Function

The LEX3N-TZ contains a built-in cleaning device that can be used without removing the trap from the line to remove rust, scale, and buildup from the valve seat.

1. Close the inlet isolation valve, then the outlet isolation valve. Wait until pressure equals atmospheric pressure.
2. Remove the cap nut and locknut slowly to release residual pressure.
3. Note the current set position of the adjusting screw.
4. Use a flat-head screwdriver to slowly turn the adjusting screw clockwise until it stops to reach the valve seat and loosen debris.
5. Slowly turn the adjusting screw counterclockwise until it stops.
6. Replace the cap nut and safely turn on steam to flush the trap.
7. Re-isolate the trap, relieve pressure, and restore the adjusting screw to the original set position.
8. Replace the locknut and cap nut, then resume normal operation.

Inspection and Maintenance

Operational inspections should be performed at least twice per year.

Part	Parts Inspection Procedure
Gasket(s)	Check for warping and damage
Seal Ring	Check for scratches and wear
Valve Stem	Check for scratches and wear
Bimetal Element	Check for wear and deformation
Springs	Check for wear on over-expansion and return springs
Screen	Check for clogging, corrosion or damage
Valve Seat	Check for rust, scale, oil film wear or damage
Body, Cover	Check inside for rust and scale

Tightening Torques

Part	Torque (N·m)	Distance Across Flats (mm)
Cap Nut	35	24
Cover	250	46
Valve Seat	30	19

Troubleshooting

Problem	Cause	Remedy
No condensate is discharged or temperature doesn't rise	Bimetal element damaged or broken	Replace with new bimetal element
	Assembly of bimetal elements is incorrect	Correct the assembly
	Build-up of foreign matter between elements	Clean the bimetal elements
	Valve seat or screen clogged with rust and scale	Use cleaning function or clean parts
	Adjusting screw not correctly positioned	Readjust the screw
Steam is blowing or temperature rises above set point	Dirt or scale on valve stem or seating surfaces	Use cleaning function
	Valve stem or seat is worn or damaged	Replace with new valve stem/seat
	Valve seat is loose	Tighten to the proper torque
	Valve seat gasket is damaged	Replace with a new gasket
Steam leakage from trap exterior	Cap nut gasket, seal ring, or cover gasket damaged	Replace with new gasket or seal ring