What should I do if the hydraulic pressure of the groove press machine doesn’t drop?

First, turn on the hydraulic knob switch to raise the groove pressing wheel. Then place the pipe on the base of the groove pressing wheel, rest the other end of the pipe on the pipe support wheel, align and level the pipe with the groove press machine, and tighten the hydraulic switch. Next, turn on the power switch (which has forward and reverse directions), and then manually move the hydraulic rod up and down.