FRAME AS-UPPER 3157123 - Caterpillar

Place photo pickup into the holder on the magnetic base. Tighten the screw. Attach the magnetic base to the fan guard assembly. Refer to Illustration 2.
When the reflective tape and the photo pickup are in alignment, the LED indicator (red light) will come on. Position the photo pickup accordingly. Note: When you start the engine, vibration of the machine may cause the photo pickup to become misaligned. Adjustment of the magnetic base may be necessary in order to realign the photo pickup.Testing and Adjusting Fan Speed
Table 2
844H Hydraulic Fan Speeds (1)
844H Standard 844H High Ambient
Altitude Target Max Fan Speed Target Max Fan Speed
240 m (787 ft) 750 rpm 840 rpm
500 m (1640 ft) 760 rpm 850 rpm
1000 m (3281 ft) 780 rpm 880 rpm
1500 m (4921 ft) 800 rpm 900 rpm
2000 m (6562 ft) 830 rpm 930 rpm
2500 m (8202 ft) 860 rpm 960 rpm
3000 m (9842 ft) 880 rpm 970 rpm
3500 m (11483 ft) 910 rpm 970 rpm
4000 m (13123 ft) 940 rpm 970 rpm
4500 m (14764 ft) 970 rpm 970 rpm
5000 m (16404 ft) 970 rpm 970 rpm
(1) The hydraulic fan speed is at high RPM. Calibration of the Hydraulic Fan System is done through Caterpillar Electronic Technician.
Connect Caterpillar ET to the machine. The ET connector is located on the control panel on the right side of the cab.
Turn the engine start switch to the ON position.
Open the ET software program.
When ET has started, start the engine. Run the engine at high idle. Warm the hydraulic oil to normal operating temperature.
Illustration 3 g01450773
Typical Example
Select "General Data" under "C27 844H". Select "Calibrations" from the "Service" menu. Select "Engine Cooling Fan Calibration".
Illustration 4 g01450770
When the dialog box appears on the screen, read the information in the dialog box. In order to continue with the calibration procedure, select the "OK" button.
Illustration 5 g01450768
When the dialog box appears on the screen, two checked boxes appear. Select the "Begin" button in order to start the procedure. The calibration procedure for the minimum fan speed will appear first on the screen.
Illustration 6 g01450772
In order to begin the test for the minimum fan speed, select the "Next" button. Follow the directions that are on the screen. After the first box has been checked, monitor the multitach for the fan