It is a known fact that few other parts are as vital as a pressure relief valve in a hydraulic system. As a major protection system of your equipment, it prevents your system circuit from being over-pressurized. As a result, it guards against expensive pump, motor, or cylinder failure due to over-pressurization. A failure in a pressure relief valve may lead to very negative system performance, system leaks, system reduced performance, or system blowout.
As a repair shop at Coastal Hydraulics, there are many instances where our clients disregard early signs, which results in costly downtime that could have otherwise been prevented. It’s important to be aware of the symptoms of a bad hydraulic pressure relief valve. The signs that must be recognized before a system is ruined are imperative for anyone who operates a system. The symptoms below are problems we see often!
Overheating Hydraulic Fluid
Excess heat is one of the first things we watch for when diagnosing a faulty pressure relief valve. The main function of a relief valve is to redirect fluid back to its tank when pressure reaches a maximum. If a relief valve is stuck in a position that is partially open or its setting is lower than it should be, it repeatedly forces fluid through a small orifice under high pressure.
This results in the creation of substantial friction, which is then converted into heat. You may have observed that the reservoir gets warm to the touch or that the hydraulic fluid gives off the smell of burnt material. If high temperatures become established, then the hydraulic fluid will get degraded and seal compounds will harden. A malfunctioning relief valve is probably the cause of the problem if your cooling system is working while the fluid gets scalded.
System Noise and Vibration
A properly functioning system will have a steady humming noise, but a faulty relief valve will make different and alarming noises. We have often encountered complaints of a chattering or hammering noise emanating from the valve’s body. This condition, termed hydraulic chatter, happens as the valve cycles or opens and closes excessively as a result of the weak spring inside the valve or due to worn-out internal valve components. Operators should also watch for the signs of a bad pressure regulator valve, which can include unusual system noises and inconsistent operation.
This oscillation leads to vibrations that can resonate throughout a plumbing system. With time, the vibrations can cause fittings to become loose and the metal pipes to crack. If the noise produced by the system while it is under stress is a whine or a beating sound that sounds like a high-pitched whistle, it is time to check the valve assembly.
Inconsistent Pressure Readings
When we connect the diagnostic gauges, we hope that the pressure values will be stable. The opposite will happen when the relief valve sticks or when the seat is compromised, or if there is an issue with the hydraulic pump relief valve. The pressure gauge will oscillate. This is why you may notice the needle jumping all over the place instead of holding a stable position.
However, there may be a situation where the system fails to achieve the required pressure because of the premature venting of the fluid by the valve. Also, if the valve sticks closed, there may be dangerous pressures that are beyond a safe pressure range. This can be a point where the valve fails to control the flow of the fluid.
Slow or Erratic System Operation
Perhaps your equipment is running slow, and you perceive it as lacking the power you know it once had. In this case, the problem could very well be the relief valve. A leaking and early-opening relief valve gives the fluid the path of least resistance, passing the oil around the actuator and directly back to the reservoir, and not to the cylinder to do the heavy lifting.
This creates problems of slow cycle times and a lack of force. This is something our technicians will identify in excavators and presses where machines can no longer lift their rated weight and may be able to move but will fight against resistance, which will signal to the user and the technicians that the hydraulic fluid pressure is being relieved somewhere at the relief valve.
Visible Damage or Leakage
In other instances, the condition will be visible without even having to turn on the equipment. A leakage of oil around the valve body or even the adjustment screw indicates the seal or O-ring has failed. A small leakage point might appear insignificant. However, this can provide a pathway for air into the equipment and for contaminants to reach the oil.
We also check the adjustment mechanism itself. If the lock nut is absent or the adjustment screw appears to be bent and/or stripped, this indicates that a person has overextended this particular valve beyond its rated specifications. A physical damage issue in a valve housing usually calls for replacing it instantly for safe operation.
Protect Your Equipment
A malfunctioning pressure relief valve should not be overlooked. The symptom list: overheating, audible noise, pressure variations, a loss of power, and leaks. That’s a cry for help coming from your equipment.
Do not wait for a failure if you feel that the valve you are currently using is affecting your hydraulic system in a negative way. Learn more about us at Coastal Hydraulics – contact our team today to schedule a check for your issue. We can check, balance, or replace the valve to make sure that your equipment is running properly!