A recent blog looked at the choice of hydraulic valves offered by Hydraproducts, all of which are CETOP valves (meaning they are interchangeable with the valves used in most hydraulic equipment), but focused mainly on solenoid valves and their function. Today we will look at relief valves and the importance of their function, as well as why those working with hydraulic equipment need to understand how they work and what they are used for. The pressure relief valve is present in hydraulic equipment to serve the basic yet vital function of limiting and relieving pressure in the system when it is too high – without this function pressure would build up and cause irreparable damage to the equipment, leading to costly replacements and also the potential for serious injury to anyone in the vicinity of the equipment, should the pressure blows. Unfortunately, this knowledge is as much as many operatives have unless they are trained or have a background in hydraulic engineering. Every time the machinery experiences a pressure issue, especially the loss of pressure, the instinctive action to take is to adjust the pressure relief valve and although this may temporarily address the issue, it is not actually fixing the root cause of the pressure issues. When the pressure valve is tampered with by several people over the course of a week or so, and each person thinks they are “fixing” the pressure issue by adjusting the relief valve, it is easy for the valve to be restricted to a dangerous level without anyone realising, until the pressure issues continue and eventually an engineer is called in. By this time there could have been substantial damage to the equipment that cannot be seen until the machinery is opened up, not to mention the risk of explosion. Any loss of pressure in hydraulic machinery should be reported to the person responsible for the maintenance of hydraulic equipment, not just “fixed” by an operator adjusting the relief valve. Armed with the knowledge that the pressure relief valves have probably been adjusted by someone with no training, the hydraulic engineer can check the settings and also the adjustability of the relief valve to see whether this has happened. The relief valve should then be checked to ensure it is still in working order, and replaced if it is not. Once the pressure relief valve has been looked at, it will become apparent whether this is masking a bigger problem elsewhere in the hydraulic machinery that needs addressing; most likely this will be a leak or seal issue that has been causing the drop in pressure that led to the pressure relief valve being tampered with. On returning the hydraulic machinery to working function it is then important to take the further preventative measure of educating operators about the pressure relief valve and why it should not be frequently adjusted in order to address pressure loss issues.