The oil pressure will go up or down based on a couple of things. First, you have to consider the viscosity of the conditioner being used in the lane machine. A higher viscosity will cause the oil pressure to increase while a less viscus conditioner will lower the oil pressure. 

Another cause of an increase or decrease in oil pressure is the volume output of conditioner.  To set your oil pump to the volume per board you wish to operate your machine at, you may need to increase or decrease the motor speed. This will cause the oil pressure to change.  

The weather can also affect into where the oil pressure needle is sitting. Cold weather can cause the oil pressure to increase in the machine. That's why it's a good idea to turn the oil pump on and let the oil circulate in the machine until you get the oil pressure to settle.

An ideal oil pressure is 30psi. To set this you must first go to Oil Calibration Test and dial in your volume per board.

Now that the oil calibration is set, take a look at the oil pressure. The tubing in the below pic can be lengthened to increase the pressure or shortened to decrease the oil pressure.