When is it time to change your elevator’s dry hydraulic power unit?

We recently took over a group of buildings that had a lot of aging ESCO dry power units that had been passed over for replacement over the years.  The other elevator equipment had been modernized over the last 15 years; Controllers, fixtures, door operators.  The power units had been forgotten and patched with some new valves.  So when is it time to replace your power unit?  And, how important is your power unit?

What does my power unit do?  Your hydraulic power unit has a motor, pump, valve and hydraulic fluid in it.  The power unit pumps and regulates the oil floor to the piston which allows the car to level into the floor correctly.

When is it time to replace your power unit?  This is a great question.  Every building will be different.  Some building’s power units can last 50 years, some buildings last 10-15. The major wear point on a hydraulic power unit is the control valve. Maxton and EECO the two major valve manufacturers suggest replacing your valve every 10-15 years.  Here are a few variables that determine how long your power unit will last.

Usage – Busier buildings will most likely need a valve replacement sooner than a sleepy building. 

Machine room environment – a temperature controlled environment that keeps the oil cool will allow for a longer life of your control valve

Oil maintenance – If you keep your oil clean, have it filtered, or have it replaced your valve will work longer.

Valve maintenance – When required, have the valve seals been replace?

If you take a closer look at the picture above you will see two old ESCO power units, you will also see fans pointed at the controllers, you will also see a dirty machine room.  This elevator room is very warm/hot coupled with age and a less than ideal machine room environment equals poor longevity of valves.  

At some buildings power units are left as the last item to be modernized.  We always encourage buildings to replace their valves on a regular basis when there are signs of wear so we can have safe and reliable running elevators.  While the power unit is typically one of the more resilient components it is also a component that the building needs to listen to their elevator company on to make sure replacement and service items are addressed quickly.

What does a new submersible power unit look like?  The great thing about a new submersible power unit is that everything is in the tank so there are no more leaks to worry about.  A submersible power unit will work for 95% of all hydraulic elevators, be aware that depending on usage, travel, capacity you may need to look into retaining a dry unit.

[New pump motor and valve are in the black box, no more leaks]

[Nice new Maxton valve and air mufler]

If you have any questions or would like additional information feel free to contact me at CraigZ@colleyelevator.com or 630-766-7230 ext. 107.

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