FW MURPHY LS200 Series Level Switch Instruction Manual

FW MURPHY LS200 Series Level Switch

Product Information

The Liquid Level Switches Series LS200, LS200N, and LS200NDVOR are products manufactured by FW Murphy. These switches are designed to monitor the liquid level in vessels and activate electrical or pneumatic devices for alarm, shutdown, or operation of dump valves.

Please read the following information before installing. A visual inspection for damage during shipping is recommended before mounting.

BEFORE BEGINNING INSTALLATION OF THIS FW MURPHY PRODUCT:

• Disconnect all electrical power to the machine.
• Make sure the machine cannot operate during installation.
• Follow all safety warnings of the machine manufacturer.
• Read and follow all installation instructions.
• OBSERVE all pressure and electrical ratings and requirements for the devices and the operating environment.
• BE SURE all pressure HAS BEEN REMOVED from the vessel before opening any pressure connections.
• Please contact FW Murphy immediately if you have any questions.

Product Information

NOTE: See Replacement Parts in manual for parts available, if needed.

Certification

• Listed for cCSAus Class I, Div 1, Grps C & D locations.
• Canadian Registration Number 0F01476.2

Minimum Allowable Specific Gravity for LS200
Note: The 6-inch float extension length is for reference only and is not available for the LS200 Series.

LS200
LS200 Liquid Level Switches with 2-inch NPT mounting are float activated to operate an electrical SPDT snap-switch (optional DPDT on some models) for alarm or shutdown of an engine or electric motor. The LS200 connects directly into the vessel wall and can be used with an FW Murphy weld collar (P/N 15050375) or FW Murphy external float chamber. Refer to the specification table below for product dimensions.

LS200NDVOR
LS200NDVOR is a float-activated, pneumatic-vent level device used to operate dump valves or similar devices. The LS200NDVOR provides a 2-inch NPT mounting with a pneumatic output for interfacing with pneumatic devices such as our FW Murphy pneumatic dump valve or with other pneumatic instrumentation. Pneumatic media devices require clean, dry, instrument-quality air or gas. This unit is supplied with a pressure regulator, filter and FW Murphy 20BPG pressure gage for improved system life and trouble-free operation.

LS200NDVOR pneumatic level switch with dump valve operator, pressure regulator and gage

LS200NDVO
Shown below is the Pneumatic level switch with Dump Valve Operator (DVO) without the pressure regulator (for those applications where the system provides a filter regulator for instrument-quality air or gas as the control medium).

LS200N
Shown below is the Pneumatic level switch without the DVO and filter regulator .

Pressure Vessel Installation

Direct Installation into the Wall of the Pressure Vessel
CAUTION: Determine that the float travel is not obstructed by the coupling in the vessel wall, internal baffles, etc. Refer to tables 1, 2, 3 and 4 for application data.

1. Make certain the float and extension are tight.
2. Before installing the level switch, apply pipe thread sealant to the threads. Screw the unit directly into the threaded connection in the wall of the pressure vessel.
3. For LS200, position the electrical connection at the bottom.
4. For LS200N, position the 1/8-inch NPT pneumatic connection on top, and the 3/8-inch NPT vent connection on the bottom.
5. Make the electrical wiring connections according to appropriate wiring diagrams for the alarm or shut-down system used. The electrical connection is ½-inch-14 NPT.
6. Insulate all electrical connections and install the cover before reconnecting electrical power.
7. Verify all pressure connections are tight before pressurizing the system.

Clearance Reference Tables

Installation with a Weld Collar
The weld collar, P/N 15050375, must be welded into the wall of the pressure vessel according to code standards and good welding practices.
NOTE: Weld collar 15050375 can be used ONLY with model LS200.

Installation Using FW Murphy External Float Chamber

1. Install the FW Murphy float chamber 15051098 or 15700799 on the outside wall of the pressure vessel using 1-inch NPT piping or use the mounting surface with a bracket. Position the 2-inch NPT threaded connection at the height where you want the level switch to operate and away from the tank wall.

2. A tee and bleed valve are typically installed at the bottom of the lower 1-inch pipe riser to allow draining of the float chamber for servicing or replacement.
   NOTE: The illustration shows a typical installation with blocking and bleed valves.

3. Install the LS200 or LS200N/NDVO/NDVOR in the 2-inch NPT connection of the float chamber. BE SURE float travel is not restricted and that the float is tight onto the float shaft.

4. To complete installation and wiring, follow the instructions for mounting directly into wall of the vessel and for wiring.
   CAUTION: Float extensions cannot be used with float chambers.

Installation and Adjustment for Pneumatic Models

1. All pneumatic models operate on the vent principle. The pneumatic signal source must be clean, dry, instrument-quality air or natural gas. The input pneumatic signal must be regulated between 30 and 70 psi (207-483 kPa) [2 -4.83 bar]. If produced gas is used as the signal source, it should be taken after gas passes through the final scrubber. A suitable filter must be positioned before the LS200NDVO to prevent liquids and/or particulates from entering the dump valve operator.
   NOTE: Check filter periodically for wear and tear and elements that hamper the flow of the pneumatic signal.

2. All pressure connections must be tight and maintained tight so as not to leak air/gas.
   CAUTION: Avoid excessive Teflon tape, which may inhibit proper operation. Each switch is set to vent on rising level at the factory and should not need field adjustment. For testing the system, we have provided the red Manual Valve Operator on the operator pilot valve.

3. You may adjust the valve seat if air/gas begins to leak. Take care when adjusting as only slight movement is necessary to stop the leakage; excessive force will bind the seating mechanism. See the instruction below for adjustment.

Replacing and Installing the DVO Assembly

NOTE: When replacing/installing the DVO assembly, tubing and fitting modifications may be required. We suggest removing the LS200NDVO/DVOR from the vessel. Relieve pressure from the vessel or use block valves before removing the LS200NDVO/DVOR.

Models LS200NDVO & LS200NDVOR
NOTE: Use clean, dry, instrument-quality gas. Use and regular maintenance of filters will improve service life and reliability.

Tools Needed
2-1/2 inch hex wrench or pipe wrench with smooth jaws / 9/16-inch hex wrench / Tubing cutters and benders.

Instructions

1. Block off and bleed the instrument gas pressure supply to the LS200NDVO/DVOR.

2. Remove the tubing between the LS200NDVO/DVOR and the scrubber dump valve, and remove the supply gas tubing (regulator [-R-] if used).

3. Remove the LS200NDVO/DVOR from the vessel (optional). LOCKOUT / TAGOUT after pressure is removed from the system.

4. If the LS200NDVO/DVOR was removed from the vessel, mount it in a suitable vise on a workbench (if possible).

5. Using the proper tools, disconnect the inlet, outlet and exhaust fittings from the existing DVO. See Figure 1. You will reconnect these to the new DVO in a later step.
   NOTE: The following steps must be done with the DVO in the upright position (on top of the LS200NDVO).

6. Remove the LS200NDVO/DVOR cover. The use of a strap wrench or a pipe wrench may help.

7. With a 9/16-inch hex wrench, loosen the hex head bolt on top of the DVO, and remove the existing DVO from the body.

8. Ensure that the adjustable orifice is fully raised upward so that the actuator arm is not bent when inserted into the body. See Figure 2.

9. Insert the new DVO into the body. The DVO manual valve operator must face away from the vessel. See Figure 3.

10. With the DVO aligned over the hex on the LS200NDVO body, tighten the valve using the 9/16-inch hex wrench. You may need to hold the DVO while tightening to keep it from rotating.

11. The pneumatic input signal should be regulated between 30 and 70 psi for proper setting of the adjustable orifice. With the float in the down position, adjust the adjustable orifice down until it touches the seat. See Figure 4. If the DVO is still leaking, make slight adjustments (1/32 turn). Excessive adjustments will lock up mechanisms. After adjusting, make sure float moves freely up and down.

12. Replace the LS200NDVO/DVOR cover.

13. Using the appropriate tools reinstall the inlet, outlet and exhaust fittings to the new DVO.
    NOTE: Use thread sealant on threads only. Do not allow excess sealant to enter valve.

14. Connect to the inlet, outlet and exhaust fittings according to installation drawings.

Accessories

15050375: Weld Collar

55050617: DVU150/DVU175 Adapter Bushing

15051098: External Float Chamber

15700799: Series 100 External Float Chamber

15000478: Float Shaft Extension for the LS200

CAUTION: Use of 1-inch extension requires additional clearance. Refer to Tables 1, 2, 3 and 4 for application data.

Electrical

Specifications

• All Models

  • Listed for cCSAus Class I, Div 1, Grps C & D locations
  • Canadian Registration Number: 0F01476.2
  • Body: Nickel-plated steel; optional 316 stainless steel
  • Float: 304 stainless steel
  • Pressure rating: 2000 psig (13.8 MPa) [138 bar] (LS200 models only)
  • O-ring: Viton
  • Process connection: 2” NPT
  • Temperature rating: -20 to 300°F (-29 to 149°C)

• LS200

  • Electrical: SPDT std. (see Electrical section for configuration/rating)
  • Wiring: 18 AWG x 36 in. (1.0 mm2 x 916 mm)

• LS200NDVOR

  • DVO valve: 3-way N.C. w/manual operator, all connections 1/8” NPT (minimum 30 psig required)
  • Filter/pressure regulator set:
  • Regulator: 0 to 75 psig (0 to 517 kPa) [0 to 5.17 bar] range
  • Maximum input pressure: 300 psig (2.07 MPa) [20.7 bar]

• LS200NDVO
  DVO valve: 3-way N.C. w/manual operator; all connections 1/8” NPT

• LS200 N
  Vent valve: 2-way N.C. w/ 1/16in. (2mm) orifice and Viton seat; Inlet: 1/8” NPT; outlet 3/8” NPT

• Approximate Shipping Weights and Dimensions

  • All models: 6 lb. 10 oz. (3 kg)
  • Dimensions: (w x h x d) 10.18 x 3.36 x .11 in. (259 x 85.34x 2.88 mm)

Replacement Parts

Order by part number designation.

• LS200
  • 15000479: Stainless steel float for LS200 (not interchangeable with L1200)
  • 15000124: SPDT snap-switch assembly
  • 15000478: 1-inch float shaft extension (not interchangeable with L1200)
• LS200N
  • 15000479: Stainless steel float for LS200N (not interchangeable with L1200)
  • 15000501: Valve stem kit
• LS200NDVO and LS200NDVOR
  • 55050621: Regulator only
  • 15000237: Regulator Gauge Assembly (includes regulator, gauge and fittings)
  • 15010267: Assembly (LS200N DVO Assembly)

The FW Murphy Gas Compressor Scrubber Level System (SLS)
In order to consistently bring you the highest quality, full-featured products, we reserve the right to change our specifications and designs at any time. FW MURPHY product names and the FW MURPHY logo are proprietary trademarks. This document, including textual matter and illustrations, is copyright protected with all rights reserved. (c) 2023 FW MURPHY. A copy of our typical warranty may be viewed or printed by going to www.fwmurphy.com/warranty.

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