When I try to calibrate the conductivity cells on a Fresenius 2000h machine I get this error: Conductivity Cells Cond less than 15 Failed, press overide calib read 15.49. What could be the problem

For what reason are you calibrating (replaced cells, sensor bd, etc.)? OLC?

Put the machine in a rinse mode then try to
calibrate your conductivity cells. I do not
know why you changed conductivity cells.
Are you receiving a conductivity stable message on the screen and what is your actual
conductivity on your external meter.The H machine will not let you enter a calibration
outside of any of the set parameters so that
is why you are getting these errors. Have you made any other changes to the machine.Was the initial problem a flow problem or a low conductivity problem?
Let us know what is going on?

Thanks for all of your suggestions. I found out it was the small test board. I initially had a low OLC problem. When I would try to calibrate the conductivity cells, I would get that error (however, the meter would display a cond of 13.7 give or take)