Overheatstop
Stop Engine Overheating Before It Starts
Installation:
A suitable place to mount the unit.
Choose a suitable position on the dashboard. It should be within reach of the driver so that the driver can easily see the unit and press the "override" switch. The OHS can be mounted on the dashboard using "double sided tape". The dashboard should be thoroughly cleaned to remove any oil or polish and the OHS box should be pressed very firmly onto the dashboard or suiteable spot, in order to stick the double-sided tape properly.
Run the sensor cable to the engine:
Disconnect the sensor from the cable at the joint. Run the sensor cable from the OHS from in the cabin to the engine compartment. Then connect the two sensor wires again as per the colours. Seal the connection properly with the heat shrink tubing which is supplied. Sensor cable is +- 1.8m.
Choose whether the OHS should switch off the engine when running to hot, or just warn the driver.
Warn and switch off option: The OHS alerts the driver and turns off the engine after 30 sec.
Only warn option: OHS warns the driver, but does not turn the engine off.
For the "Warn and Switch Off option":
In this case, a wire that gives power to the engine to keep it running and turns off the engine must be selected.
Make sure that shutting off this power supply to the engine, will not interfere with any other functions, such as the vehicle's computer.
This wire should then be cut and the brown wire of the OHS should be connected to the supply side and the blue wire of the OHS should then be connected to the engine side, can be a wire going to the engine / ignition / fuel pump or diesel cut off valve.
The green wire of the OHS is grounded to the vehicle.
This connection can be tested as follows: The engine should start when both wires are connected and should switched off the engine when the blue wire is disconnected.
- Brown wire of the OHS should be connected to the voltage supply side
- Blue wire of the OHS should then be connected to the engine / ignition side.
- Green wire of the OHS is grounded to the vehicle.
Sensor wiring:
Note the sensor wires are also brown and blue but are already connected to the sensor. The green wire from the sensor wires is to be connected to the vehicle's oil pressure sensor, if so requested.
For the "Warning only option":
Connect the brown wire of the OHS to a point that delivers 12volt when the vehicle’s engine is turned on and that does not receive power when the vehicle is turned off. In this case, the blue wire is not connected anywhere.
The green wire of the OHS is grounded to the vehicle.
Fit the temperature sensor:
Mount the temperature sensor preferably against the "top" or against the block near the "top". Avoid the "inlet manifold" itself, because it is cooled by incoming cold air. Also avoid the "exhaust manifold" and its direct environment. The sensor's mounting piece is then tightened under an existing bolt or nut of 8 to 10mm thickness.
Note that the first 50mm from the sensor's, the cable there is a rigid wire so that it can be bent away from the engine, in order to prevent the cable from touching the hot engine block.
The green oil pressure sensor wire from the OHS should then be connected to the vehicle's oil pressure sensor.
Wrapping Up:
Attach all wires neatly out of the way and secure it to ensure that wires are not damaged due to heat or vibration. In particular, make sure that where wires pass through panels to the cabin, they are adequately protected from damage due to abrasion with vibration. Ensure all screws are tightened firmly.
Calibration:
The unit comes pre-calibrated at 95 degrees. Vehicle working operating temperature must be checked and recalibrated if necessary.
In order to prevent the OHS from turning off the engine during the calibration process, the connection of the power supply to the engine can be temporarily changed to be as for the "Warning Only option" described above.
To calibrate the OHS, the engine must be warmed up to its normal running temperature. The engine should then be turned off. The calibration process is activated by connecting (bridging) the two calibration contacts (screws) of the OHS for two seconds. If the OHS is installed in such a way that it can switch the engine off, then it will switch the engine off as soon as the calibration process starts. The display will then show that the
OHS unit is now in calibration mode. The calibration process will take 15 minutes and the remaining time will be shown on the OHS screen. During this period, during which the engine's oil and water do not circulate, the temperature will rise momentarily above normal. The current engine temperature, the highest temperature measured during the calibration process and the previous Alarm temperature will be displayed on the screen. Once the calibration process is completed, the highest temperature plus 5ºC is then stored as the new Alarm Temperature, the Engine temperature and the new Alarm temperature will be displayed and the power supply to the engine will be switched on again.
If the OHS needs to turn off the engine when its running to hot (see "Warn and Switch Off option" above), and the connection is temporarily modified to do the calibration then it should be connected again to allow the OHS to turn off the engine when running to hot.
The coupling should be tested again by starting the engine and check whether the engine will switch off when the blue wire is disconnected.
Caution not to calibrate on a colder than normal engine! Engine must be at normal operating temperature.
Note that if the engine has not been warmed to its normal operating temperature, then a too low temperature is actually calibrated. In such a case, the OHS will warn and switch the engine off while the engine is not running hot. This will cause inconvenience and frustration to the driver, whom may not know how to re-calibrate the system. The calibration process must be redone when normal working engine temperature is reached.
Caution not to calibrate on an engine already running to hot! Engine must be at normal operating temperature.
If the engine is running to hot and the calibration is then done, a too high temperature will be stored as Alarm temperature and the OHS will not be able to protect the engine. Therefore, be extremely careful not to do the calibration on an nearly overheated engine.
While the OHS is on and the engine temperature is lower than the Alarm temperature, then both the temperatures will be shown on the OHS screen as indicated in the picture below and the green LED will be on.
Alarm during over-heating / running to hot
The OHS warns when the engine temperature rises above the Alarm temperature. The "buzzer" will beep clearly and the red LED will flicker. If the OHS is installed to turn the engine off, the OHS will do so after 30 seconds of warning. During this period, the remaining time is counted down on the screen.
After 30 seconds, if the engine temperature is still higher than the Alarm temperature, the OHS will remain in the Alarm phase for another 30 seconds. Once the temperature has dropped to below the Alarm temperature, the buzzer is switched off and the OHS will go into a "Cool Down Period".
Cool down period:
The OHS will not switch the power supply to the engine on again until after the engine temperature drops to 10 degrees below the Alarm temperature. During this period the buzzer will beep and the red LED will flash every 30 seconds. After the cooling down period, the green LED will come on and the screen will show the normal engine temperature. Then the engine will be able to be turned on again.
Faulty sensor on the OHS:
If the temperature sensor of the OHS is faulty, a warning will appear on the OHS screen. The engine will not turn off and no other functions will be performed.
