Frequently Asked Questions

Q. I just installed a Needlemeter water unit and it is not working. What should I check?

A. 1. Verify that both the control box and the truck have the SAME voltage: 12V or
24V, negative or positive ground.
2. Check the wiring connections:
RED wire - power hook-up
BLACK wire - ground
3. Check that the connectors fit properly:
Control box to the sensor - (2) 4-pin and (1) single pin connector
Control box to the dial - 2-pin connector
4. Ensure that the red and blue ring terminals on the back of the dial are on the
proper posts and are fastened securely.
5. With proper connections the orange dial outputs from the control box should read
.5 volts with the tank full.

Q. My Needlemeter dial reads a level but will not reach "FULL"

A. 1. With the tank full, turn the adjust knob on the control box to bring the dial to full.
2. Disconnect the (2) 4-pin connectors from the control box to the sensor. With the
unit powered, ground each of the 8 pins on the control box to the chassis. Each
pin grounded should make the needle move approximately 1/8. If any pin does
not move the needle then proceed to the next step. (NOTE: All 8 pins need to
be grounded at once to read full.)
3. Check the cable between the control box and the sensor for damage or cuts.
4. With the tank full, use on ohm meter to check the continuity between the 8-pins
on the sensor connector and the chassis. It should read approximately 15K
between each pin and ground.
5. Be sure that if the sensor is in the fill tower or mounted anywhere other than the
tank top, that is was ordered to that specification (one or more probes may not be
making water contact if it was ordered improperly)

Q. My Needlemeter dial reads a level but the tank is empty.

A. The sensor may require cleaning. Debris or build-up may have caused false
readings.

Q. How do I clean the sensor?

A. Disconnect the sensor from the control box. Loosen the compression fitting, remove
any debris that may have adhered. If necessary use fine, detergent free steel wool to
further clean the probes. Wipe down the stainless steel tube and assemble the
probe. Reinstall in the tank and reconnect to the control box.

P.O Box 821

Holbrook NY 11741-0821

Telephone: 1 (800) 843-6465

Fax: 1 (800) 582-5319

E-Mail: customerservice@mcproducts.com