Low-level switch does not change state.

If the low-level switch does not trip before the reservoir or tank runs out of fluid, check the following:

1. Verify the switch is wired correctly

The wiring depends on the reservoir or tank being used:

• Standard reservoirs use a 4-wire sensor cable. Only the blue and black wires are used for the low-level switch circuit.
• 4-gallon remote tanks use a 4-wire sensor cable. Only the blue and black wires are used for the low-level switch circuit.
• 2, 6, 15, and 30-gallon remote tanks use two red wires for the low-level switch circuit.

Ensure the correct wires are connected to the appropriate terminals as shown in the wiring diagram below.

2. Verify the float orientation

The float contains two dots on one end that determine the switch operation.

• Two dots facing up: The contact closes when the fluid level is low.
• Two dots facing down: The contact opens when the fluid level is low.

Make sure the float orientation matches the desired control logic for your application.

3. Verify the float is installed correctly

If the float has fallen off the brass stem:

• Reinstall the float in the desired orientation.
• Install the retaining e-clip to secure the float.

• If the e-clip is missing, contact Unist to purchase a replacement.

   

4. Test the switch for continuity

The expected continuity depends on the float orientation and position:

If continuity is present when it should be open, or open when it should have continuity, the internal reed switch has failed and the low-level switch assembly should be replaced. Contact Unist for a replacement assembly.