CNC hydraulic pipe bender on the yuken control device control knob role is to control the hydraulic oil pressure range of numerical value adjustment.
Pressure adjustment range (MPa): This series of oil pumps have a number of pressure adjustment range corresponds to different letters, as shown in the example, the letter "B" corresponds to the pressure value adjustment range of "1.2 ~ 7" (other letters correspond to the range see the table below)
The CNC hydraulic pipe bender has this yuken control device knob role is to control the hydraulic oil pressure value adjustment. The range of other letters correspond to the table below)
Representative letters corresponding to the range B1.2~7C1.2~16H1.2~21K2.0~28
Now from your photo yuken controller knob value has been adjusted to the maximum value, which may be a bad habit. Though in the case of the bender equipment model is older, maybe maxing out the pressure value has a bit to do with the age of the equipment as well.
But as long as the bender can still be used normally, do not move this knob, because the old equipment is best not to change. And this knob control value has been the largest, if the role of the equipment has anomalies, and then adjust the knob can only adjust the value of small.