We have in recent days seen a new development with respect to hydraulic oil heating up and oil tempratures rising. I am not sure if this is due to the fact that elevator contractors are reluctant to add oil into the oil tank (legislative requirement prevents them from doing so without reporting on the oil added) or if there is a pump failure epidemic going on. What we are sure about though is that in some cases, some contractors are approaching building owners after years of normal service to sell them oil cooling devices.
Obviously, if your building is 20 years old and had no oil heat issues, the same rule should apply on a forward going basis unless you have changed the way you operate the elevating device. For example, if your building population density went from 100 passenger to 300 passengers, then one can presume that the building load is due to the new demand which increases the frequency of use. But if the population density is the same and the operation of the elevator (usage) is unchanged, the oil should not heat up unless:
1. The quantity of oil is now reduced which means that there is less oil to disipate the heat, hence the oil temprature would rise; or
2. The pump or motor are faulty and one of them (or both) are on their way out.
So before you rush to buy the oil coolers, make sure that you look at the reasons the oil temprature is increasing.