First, the pointer does not move or rarely moves, the reasons may be the following: 1. The checker valve is not open 2. The pointer is loose, and one end of the pointer touches the dial. 3. The center hole of the seal gasket of the calibrator is blocked, and the working medium cannot be introduced into the pressure gauge. 4. The medium in the oil cup of the calibrator is too dirty, blocking the spring tube or transmission channel. 5. The rubber cup at the top of the verifier screw is damaged or the spring tube is broken, causing a large amount of oil leakage.
The second is the pointer backwards. A leak in the calibrator or a non-smooth needle valve on the oil cup caused poor sealing, or a crack in the spring tube. These failures are common and easy to resolve.
The third is the phenomenon of needle jump. The teeth of the sector gear may be rusted, worn, and dirt. Or the pointer shaft is tilted and the curve rubs against the dial on one side.
The fourth is that the pointer does not return to zero, the return error and the tapping displacement are out of tolerance. The hairspring is not tightened or enlarged enough, or the pointer is loose.
