ASA Hydraulik ILLZTT Proportional Oil Temperature Sensor - Variable Fan Speed, 1/2 inch BSP

This is not a switch. The ILLZTT is a proportional temperature sensor, so instead of slamming the fan on at one temperature it reports the actual oil temperature and lets a controller vary the fan speed to suit. Fitted with an ILLZTC controller, fan speed rises with oil temperature from 45 degrees C and reaches maximum speed at 55 degrees C, which means a quieter machine and a fan that is not running flat out all day. It screws into a 1/2 inch BSP port on the ASA coolers and the TT rail connector blocks. Pick your model below and it is on its way.

Ways to buy:

• Off the shelf - two variations in the picker below, one with an AMP Superseal 1.5 connector at IP69K and one with a Deutsch DT06-2S connector and a 250mm cord at IP67.
• You must also buy a controller. This sensor does nothing on its own. It needs an ILLZTC12-2K for a 12V system or an ILLZTC24-2K for a 24V system. Order the matching controller from the fan controller listing at the same time.
• Building a reversible fan drive? The ILLZTCB00 reversible fan drive controller specifically requires the ILLZTT5069K sensor, so take that one.
• Just want the fan on and off? Then you do not need this. An ILLZTH on/off temperature switch is cheaper, simpler and needs no controller.
• Not listed? Call us and we will factory-code it. Other sensor cord lengths and connector styles exist in the ASA range and we can order them in.

Pick your model

Both are 1/2 inch BSP male thread. Both require an ILLZTC controller to do anything.

What is in the box

• One ILLZTT proportional temperature sensor with a 1/2 inch BSP male thread, built and tested in Austria.
• On ILLZTT5067K: the sensor with its 250mm cord and Deutsch DT06-2S connector fitted.
• NOT included: the controller. This sensor has no output stage and cannot drive a fan. Without an ILLZTC12-2K or ILLZTC24-2K it will not run anything.
• NOT included: the mating connector or loom, sealing washer or bonded seal, cable, fuse, and any port adaptor if your port is not already 1/2 inch BSP.
• NOT included: extension cable. The IP67 model gives you 250mm of cord, which reaches a junction, not a cab.

Specifications

How to choose

• Confirm you want proportional, not on/off. Proportional control means less noise, less current draw at low load and longer fan life, because the fan only works as hard as the oil temperature demands. It costs you a controller to get there.
• Pick the sensor by connector, then buy the controller by voltage. The two sensors do the same job. AMP Superseal 1.5 at IP69K for washdown and sealed mobile looms, Deutsch DT06-2S at IP67 with a 250mm cord if the machine is already on Deutsch.
• 12V machine takes the ILLZTC12-2K, 24V machine takes the ILLZTC24-2K. The sensor is the same either way. Get the controller voltage wrong and nothing works.
• Twin fan cooler needs two controllers. One controller drives one fan, so a twin fan cooler takes two.
• Reversible fan drive means ILLZTT5069K. If the plan is the ILLZTCB00 reversible drive controller so the fan can blow debris out of the core, that controller calls for the ILLZTT5069K specifically.

Technicians Advice

A proportional sensor is only as good as the oil it is sitting in, and this is where most variable speed installs go wrong. The element is in the nose of the sensor body, so the tip has to be immersed in flowing oil. Screwed into a boss welded on the outside of a tank, half its heat path is tank steel and the air around it, and you get a lazy reading that lags the real oil temperature by minutes and makes the fan hunt.

In a tank, put it below minimum oil level, in the body of the oil, away from both the suction strainer and the return diffuser. In a cooler rail connector block, it is already reading the oil going through the core, which is the ideal spot.

Understand that a sensor in the return line reads hotter and reacts faster than one in the tank, because return oil has just come off the relief valve or the cylinder and has not mixed with the tank volume yet, and on a cycling machine you will see it swing 10 degrees or more while the tank barely moves.

With a proportional sensor that is actually useful, because the fan tracks the load instead of waiting for the whole tank to heat up, but it does mean the fan will be up at full speed while a tank mounted sensor would still be idling. Pick the position to suit which you care about: protecting the oil in the tank, or catching the heat as it is made.

The 45 to 55 degree window is narrow on purpose and it is below the temperature most oils start to suffer at, so the fan is at full song well before anything is in trouble. If your machine normally sits above 55 degrees the fan will simply run flat out and you have a sizing problem, not a sensor problem.

Wiring matters on a proportional signal. Keep the sensor lead away from the fan power leads and any solenoid or ignition wiring, because a low level analogue signal running alongside a switched inductive load picks up noise and the fan speed will surge for no visible reason. Run it in its own path, keep the connector out of standing water even on the IP69K unit, and support the 250mm cord on the IP67 unit so its weight and machine vibration are not hanging off the sensor body.

Seal the 1/2 inch BSP parallel thread on a bonded seal or O-ring against a clean flat face, never with thread tape, and nip it up firm rather than hard, because over-torquing distorts the body and shifts the calibration you paid for.

Official Datasheets

📄 Temperature Sensor IP69K (PDF)📄 Temperature Sensor IP67 (PDF)

Complete your setup

Do not order the sensor on its own. It needs an ILLZTC controller to drive the fan.

Fan Temperature ControllersTemperature SwitchesTT Rail Connector KitsReplacement Fan Kits

Need help choosing? Call 1300 146 737 or email sales@mhfgc.com.au - real technicians, real answers.