Pressure Switch Troubleshooting

The pressure switch is a pressure control device integrating pressure signal detection output, alarm display and other functions. It can measure and control the pressure of various gas and liquid media. The pressure switch mostly adopts the threaded joint or welding installation method, and does not need other objects or methods to assist reinforcement, the installation and use are simple and convenient. However, in daily life, the pressure switch may have some failures, which hinder people's normal use. Next, we will explain several common failures of the pressure switch such as no output signal from the pressure switch, poor sensitivity of the pressure switch, and too fast signal from the switch and so on. Today, I will briefly describe and analyze the above these fault problems and how to deal with them, hoping to help you solve them better.

Common troubleshooting

The pressure switch has no output signal

The micro switch may be damaged, and the micro switch should be replaced in time; the setting value of the switch is too high, and the setting value should be adjusted to an appropriate state; the wire connected to the micro pressure switch is not connected properly, check the wire, and reconnect the line; the pressure-sensitive element is poorly assembled, and there is a phenomenon of jamming. It should be reassembled to make the action sensitive; if the pressure-sensitive element is damaged, and a new element should be replaced in time.

Poor sensitivity of pressure switch

If the friction of the transmission mechanism such as the push rod or the plunger is too large, it should be reassembled to make the action sensitive; the contact stroke of the micro switch is too long, and the stroke of the micro switch should be adjusted; if the screw and the push rod are not adjusted properly, you should adjust the screw and the push rod position; if the installation is uneven or inclined, you should adjust the pressure switch to be installed vertically or horizontally.

Pressure switch signaling too fast

If the damping hole of the oil inlet is large, the damping hole should be changed to a smaller size, or a damper should be installed on the measuring pipeline; if the isolation diaphragm is broken, the isolation diaphragm should be replaced in time; if the system pressure fluctuates or the impact is too large, a damper should be added to the pipeline.

Air pressure problem leads to air leakage

The air pressure is less than 0.65Mpa and continues to decrease, but the gas has been discharged from the vent hole D of the pressure controller. The tympanic membrane of the valve, the tympanic membrane spring or the bleed valve are damaged, and the seal is invalid; the bleed hole C is blocked; the bleed check valve leaks, the bleed check valve spring fails due to damage, and the leather cup ages and leaks. It is necessary to check the sealing condition of the valve tympanic membrane, tympanic membrane spring or deflation valve. If damaged, replace it with a new one to clear the vent hole C; replace the deflation check valve and its spring and the leather cup.

There is an air leak between the upper and lower shells, and air bubbles are generated after being applied with washing powder water. The castings of the upper and lower shells are defective; the sealing ring between the upper and lower shells is damaged or the fastening bolts are loose; the tympanic membrane of the valve is aging, so that air leaks from the adjusting screw. At this time, the surface of the shell needs to be cleaned, and the defect should be repaired with metal repair agent; the sealing ring or fastening bolt should be replaced, and the valve drum should be replaced.

The air pressure is normal, but the air keeps leaking from the pressure switch (pressure controller) vent hole D. The tympanic membrane of the valve is in contact with the deflation valve and the fit is not tight, forming a gap and causing air leakage; the tympanic membrane spring is damaged or invalid, and its valve cannot be pressed tightly. It is necessary to check the sealing condition of the valve tympanic membrane and the deflation valve, and replace the new one. When the air pressure is lower than 0.65Mpa, it means that the screw is adjusted too loosely, the air pressure of the tympanic membrane of the valve is low, and the air release valve is leaking due to aging. The adjustment screw needs to be screwed in to replace the air release valve.

After the air compressor stops sucking air, the hole D or C does not vent, but the air pressure drops rapidly. The intake check valve is aging, damaged, and the seal is not tight and leaks, and the spring of the intake check valve is damaged and fails. It is necessary to check the intake check valve and its sealing condition, and replace it with a new one and the spring of the intake check valve if it is damaged.

The air pressure is higher than 0.70Mpa and continues to rise, but the air does not release from the air release hole D or C. The tympanic membrane spring is stuck; the air hole on the air release valve is blocked; the spring of the air release check valve is stuck; the valve stem is blocked. In this case, it is necessary to replace the tympanic membrane spring, clear the air hole on the deflation valve, replace the deflation check valve spring, and grind or replace the valve stem.

When maintaining the pressure switch (pressure controller), pay attention to keep the seals, joints and air inlet and outlet of the pressure switch (pressure controller) clean to prevent dirt and impurities from entering and causing pipeline blockage or poor sealing. Its internal rubber valve and rubber material are replaced to prevent premature aging of rubber parts and affect safety. After maintenance, the working performance of the pressure controller should be checked and calibrated with an accurate pressure gauge, and it can be used only after the adjustment is qualified.

If the air pressure is higher than 0.70Mpa when deflated, it means that the adjustment screw is too tight, the compression of the tympanic membrane spring is overloaded, and the tympanic membrane deflation pressure of the valve is too high. It is necessary to unscrew the adjustment screw a little to reduce the compression of the eardrum spring.

Alarm problem of pressure switch

The alarm sound is harsh, so it has the function of warning reminder. Therefore, in many safety-related productions, the equipment used will have an alarm function. Once an abnormality occurs, an alarm will be issued to remind. Because the pressure switch (such as air compressor pressure switch 24V) has to work in a high-pressure environment for a long time, if the pressure exceeds the standard, there will be a big problem. Some pressure switches will alarm even when the pressure is normal, even very frequently, which affects normal production. In this case, there is a problem. It is necessary to investigate the problem. Of course, the premise is to find the reason first.

First of all, the problem of the equipment itself must be ruled out. If it is determined that the pressure switch is broken, just replace it with a new one. If the damage can be repaired, it can be returned to the factory for modification. If it is not the problem of the pressure switch, then you can try to replace a larger gas tank, which can reduce the pressure in the tank and reduce the pressure exceeding the standard in the container.

It may be that there is a module used by the pressure switch with strong electromagnetic interference on site. Or the host pressure switch fails at a fixed time or when high-power equipment starts. The field displacement pressure switch module needs to add module shielding device (wrap the module with tin foil).

The above are some common failure problems of pressure switches for your reference. When we find problems during use, we should ask the after-sales personnel of the manufacturer to solve them in time.