The Pro Shot L4 has had many revisions over many years but in essence has remained the same. The L4 uses the older but still very accurate and reliable wire suspended compensator method of self levelling. See this post on different types of self levelling HERE
Calibration is pretty simple in that you set up the Pro Shot L4 on a stable surface roughly level off the bubble vial to get the laser into self levelling range and check the accuracy of the laser of both axis. A standard way of checking calibration is to mark the height of the laser beam on your chosen axis on the wall some distance from the laser, ideally in low light conditions. Rotate the body of the laser 180 degrees so the opposite side of the laser is facing the marks on the wall let it self level and mark the new height, the closer the two heights are the more accurate the laser is. As an example if the laser heights are 2mm apart from each other at a distance of 10m from the laser to the wall then for that axis the laser’s accuracy is +/- 1mm over 10m. Repeat the operation for the other axis.
The diagram above indicates the two axis “X” and “Y”.
To adjust or calibrate the laser level you need to turn a calibration screw inside the the L4 corresponding to the axis you need to adjust. The calibration screw are located behind the two black rubber covers situated beneath the control panel, this is also indicated on the diagram above.
To adjust the X axis remove the corresponding black plug and using a hex driver (on most variants 3/32″ size) rotate the screw in one direction check your wall markings to see if laser beam is being shifted toward the centre position between the upper and lower marks. If not, rotate the screw in the opposite direction, the perfect position for the laser beam is to be exactly between these two markings. Repeat the operation for the other axis if required and re-check. HINT remember to re-level the laser level body using the bubble vial each time you move the laser level to make a new mark.
A final HINT, it is possible that a Pro Shot L4 may not be able to re-calibrate due to a damaged compensator. You can normally tell the compensator is damaged if the laser will not rotate even when the bubble in in the centre of the vial or that you find that you cannot adjust the screws sufficiently to bring the laser into level.
There is another aspect to calibrating a Pro Shot L4 or any other wire suspended compensator laser level and that is the bubble vial itself. As indicated previously the bubble vial is just there to get the body of the laser roughly levelled and the compensator into self levelling range. If the bubble is out then putting the bubble within the circle may not get the laser into range and it will not begin to rotate. Adjusting the bubble is a bit of an art in itself and the principles require a post of its own some time in the future. Essentially its a process of trial and error, powering up the laser and manoeuvring the bubble around the vial until the laser starts to spin and finding the optimum or central position. The vial then needs to be adjusted by screws located around it so that the bubble is placed in the centre. Remember it is just a rough levelling vial, it does not effect the accuracy of the laser level how central the bubble is along as it is in the circle and the laser rotates. This type of adjustment is best left to those with experience or knowledge of this type of thing and does require removing the housing of the laser level so I do not recommend doing this at home.
As always the Laser Level Review does not take any responsibility for your actions whilst using our guide, if you are at all unsure do not attempt to re-calibrate your laser and send it to a laser level service centre.
Had experience of this model and have anything to add please comment below.
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