Madison M3326 Liquid Level Sensor Instruction Manual

1. Introduction

The Madison M3326 is a subminiature vertical float switch designed to detect high or low liquid levels within a container. Constructed from polypropylene, this sensor is suitable for various applications, including food material handling, agriculture, and contact with many industrial fluids. Its polypropylene composition makes it ideal for food equipment applications operating at temperatures up to 221°F (105°C), such as food service steamers and proofers.

Figure 1: Madison M3326 Liquid Level Sensor. This image displays the compact design of the vertical float switch, featuring a polypropylene stem and float, with two brown lead wires extending from the top. A white hexagonal nut and black O-rings are visible for bulkhead mounting.

2. Specifications

Note: Switches are rated for resistive loads. Refer to UL guidelines for current (Amperes resistive) at different voltages for proper electrical considerations.

3. Setup and Installation

1. Mounting Location: Select a suitable location in the container where the liquid level needs to be monitored. Ensure the sensor will be positioned vertically.
2. Drill Hole: Drill a 3/8-inch hole at the desired mounting point. The sensor uses a 3/8-16 UNC bulkhead mounting thread.
3. Insert Sensor: Insert the sensor through the drilled hole. Secure it using the provided nut and O-rings to ensure a watertight seal. Tighten the nut firmly but do not overtighten to avoid damaging the polypropylene material.
4. Electrical Connection: Connect the 24-inch, 22 AWG Teflon insulated lead wires to your control circuit. The M3326 features a Single Pole, Single Throw (SPST) switch. Ensure connections comply with local electrical codes and the specified electrical ratings (120 VAC, 0.12A; 100 VDC, 0.10A; 24 VDC, 0.30A; 12 VDC, 0.30A).
5. Load Compatibility: Verify that the connected load is resistive. This switch is rated for resistive loads only. Consult UL guidelines for appropriate current ratings at various voltages.

4. Operation

The Madison M3326 operates as a simple float switch. As the liquid level in the container rises or falls, the polypropylene float moves along the stem. This movement actuates an internal switch, changing its state (open or closed). The sensor can be configured to detect either high or low liquid levels depending on its orientation and wiring within the control circuit.

• Liquid Level Detection: The float's position relative to the stem determines the switch's state. When the liquid level reaches the float, it will either rise or fall, triggering the switch.
• Switch Type: The sensor incorporates a 15 Watt, SPST switch. The electrical output changes based on the liquid level.
• Resistive Loads: Ensure the connected electrical load is resistive to prevent damage to the switch and ensure reliable operation.

5. Maintenance

Regular maintenance helps ensure the longevity and accurate operation of your Madison M3326 liquid level sensor.

• Cleaning: Periodically inspect the float and stem for any buildup of debris, residue, or foreign material that could impede the float's movement. Clean gently with a soft cloth and appropriate cleaning agents compatible with polypropylene.
• Inspection: Check the lead wires for any signs of wear, fraying, or damage. Ensure the bulkhead mounting nut remains securely tightened and the O-rings are intact to maintain a watertight seal.
• Material Compatibility: Confirm that the liquid being monitored remains compatible with polypropylene. Exposure to incompatible chemicals can degrade the sensor material over time.

6. Troubleshooting

If the Madison M3326 sensor is not functioning as expected, consider the following troubleshooting steps:

• No Switch Activation:
  • Verify that the float is moving freely along the stem. Obstructions or buildup can prevent proper operation.
  • Check the liquid level to ensure it is reaching the activation point of the float.
  • Inspect electrical connections for proper wiring and secure contact.
• Incorrect Readings:
  • Ensure the sensor is mounted vertically and not at an angle.
  • Confirm that the specific gravity of the liquid is within the operational range for the float (Float SG: 0.60). Liquids with significantly different specific gravities may affect float buoyancy.
• Switch Failure:
  • Ensure the electrical load connected to the switch is resistive and does not exceed the specified electrical ratings (15 Watt, 0.12A at 120VAC, etc.). Non-resistive loads or overcurrent can damage the internal switch.
  • Check for chemical compatibility. Certain aggressive chemicals, such as gasoline, are not compatible with polypropylene and can cause rapid material degradation and sensor failure.

7. Warranty and Support

For specific warranty information, technical support, or assistance with your Madison M3326 Liquid Level Sensor, please contact Madison Company directly. Refer to their official website or product documentation for contact details and warranty terms.