1. Insufficient Pressure
Symptoms: Pipe ends cannot fit tightly during welding, the flange is too small or asymmetrical, and the weld zone is not fully fused.
Common Causes:
Hydraulic pump wear or internal leakage, output pressure does not reach the set value;
Damaged relief valve, broken pressure adjusting spring, or stuck valve core, causing the system to fail to build pressure;
Insufficient oil in the tank or blockage in the inlet pipe, causing the pump to suck in air;
Leaks in the hydraulic system (e.g., loose joints, aged seals).
2. Excessive Pressure
Symptoms: Heating plate is difficult to remove, pipe is severely deformed, and may even damage equipment structural components.
Common Causes:
Relief valve pressure adjusting handle is mistakenly set to too high a position, or the pressure adjusting spring is too tight;
Pressure gauge malfunction, incorrectly displaying a high-pressure state;
Oil pump check valve seal failure, causing oil backflow and continuous pump operation for increased pressure;
High ambient temperature, hydraulic oil volume expansion causing pressure rise.
3. Unstable Pressure (Large Fluctuations)
Symptoms: The pressure gauge pointer jumps frequently, and the pressure fluctuates during welding, affecting the consistency of the weld.
Common Causes:
Air mixed in the oil, leading to increased compressibility and pressure fluctuations;
Wear of the relief valve core or fatigue of the spring, losing stable pressure regulation capability;
Hydraulic oil contamination, clogging the damping orifice or control valve passage;
Accumulator failure, unable to absorb system pulsations.
4. Slow Pressure Response
Symptoms: After the operating handle is actuated, the clamp advances slowly, and the pressure rises lags behind.
Common Causes:
Hydraulic oil viscosity is too high or oil temperature is too low, resulting in poor fluidity;
Insufficient oil pump speed or insufficient motor power;
Partial blockage in the pipeline or partial blockage of the throttling orifice.
