The Reset button is a simple push operated button. When you press the reset button, it creates a record of the application while at the same time zeroes the monitor.
The reset button should last for years with normal use. However, over time, it is possible that build-up of material can cause the button to not work, even hinder it from being pressed if the material is hardened.
Check the cabling for cracking or pulled wires as a simple visual inspection should tell you if it is the button itself that is the issue.
Another test is to press F1 on the keypad and see if the monitor resets. F1 on the keypad has the same function as the button. If the monitor does reset and zero out, then most likely it is the button. If the monitor does not zero, then there is another option.
First a couple of question: Do you or are you receiving the data from the monitors? Or are you just using the monitors as a visual reference? If you are not getting the data from the monitor and just use it as a visual reference, then give us a call at 888-222-9828 and we will go from there to fix the button issue.