When the sun sets, the most important tool on some jobsites becomes a light tower, especially during those times of the year when daylight is shorter and deadlines are looming. Without a source of light, work can’t continue. Light towers are reliable and have a compact design to
perform their duty without taking up a lot of space. However, if not properly maintained, a light tower might turn off the lights and shut down work on nighttime jobs.
Fortunately, light towers don’t require a lot of work to keep running. However, users should still familiarize themselves with the machines and take precautions to keep their light towers running properly.
“Before operating the light tower, contractors should read the operator’s manual,” says Fred Pickett, a generator field service technician with Ingersoll Rand. “Be familiar with the operator’s manual first. Usually, it’s the last thing contractors look at.” The operator’s manual will highlight safe operating and maintenance procedures. Knowing what to look for will mean less downtime when a problem occurs.
There are three things contractors should check on a light tower at the start of every work day: air filter, oil level, and coolant level. Inspect the air filter before starting the engine — remove the air filter and knock any dust out of it. Before starting the engine, check the oil and coolant levels. Checking the oil on a light tower is similar to checking the oil in a car — remove the dipstick, wipe it off, replace it and then remove it again to see the oil level. Coolant containers are clear, so checking the coolant level requires only a visual check to make sure there is enough coolant in the container.
The most basic maintenance concerns are oil and air filters. For most light towers, including the Ingersoll Rand LightSource light towers, it’s recommended that the oil be changed every 200 hours. Air filters should be changed every 500 hours. These recommendations will change based on the environment where the light tower is being used.
While light towers are used in special event applications such as concerts or sporting events, the equipment is most often found on dusty construction sites. The dirt in the air takes a toll on light towers, and contractors need to make sure they are changing the oil and the air filter as required when working in these conditions. When working in dirty environments, the air filter should be changed with the oil.
“A dirty air filter on a diesel engine is going to make the engine lose horsepower because
it can’t get any air. As soon as the light tower is in a dirty environment, the air filter will last only 100 to 200 hours,” says Jack Wright, also a generator field service technician with Ingersoll Rand.
“The best maintenance a contractor can do with light towers is to regularly change the
filters when they need to be changed and to use new, clean fuel,” says Pickett. “Using clean fuel keeps the engine running with better efficiency. Fuel that has been sitting in a tank for a long period of time may collect dirt or water. The longer fuel sits in a tank, the lower the rating on the fuel will be.”
The need to change light bulbs will not occur as often as oil or air filters. Under optimum conditions, high-pressure sodium bulbs have a lifespan of 24,000 hours, metal halide bulbs will last 12,000 hours and tungsten bulbs have a life of 2,000 hours.
These lights are very hot and should not be changed when the engine is running. Shut the machine down and give the bulbs proper time to cool. Use gloves to remove the old light bulb and to screw the new bulb in.
Take care of the decals on the machine on a monthly basis to make sure they have not become damaged or illegible. It’s important to make sure the decals are intact — they contain important safety and operational information that operators need to know.
“Never perform maintenance with the engine running,” says Pickett. “If changing parts, the battery should be disconnected so there is no possibility of the engine starting. If you’re working on the battery, wear protective clothing and eye protection.”
It’s a good idea to keep track of your tools, especially when working with the battery. Never lay a tool on the battery when working on the machine. Leaving tools on the battery is an unsafe practice because the amps that get drawn on the battery when shorted by a misplaced tool can be hazardous. Tools should always be kept off the machine. It’s easy to forget where a tool has been placed, and any tool left on top of the engine, radiator or generator could fall into the machine when started and cause major damage.
Let There Be Light
Light towers are primarily designed to tackle one task — provide light on the jobsite. If contractors need to power other components, getting a generator onsite should be considered. Use only OHSA-approved, three-pronged plugs in the receptacles. Make sure the cord on the component that is plugged into the receptacle is not damaged and never put any stripped or bare wires into the receptacle.
Pickett has seen contractors try to use the light tower to power a jobsite trailer, a function the machine is not designed to perform.
“The Ingersoll Rand LightSource has a 6-kilowatt generator. When the four lights are running, they consume 4.4 kilowatts. That leaves 1.6 kilowatts to use for auxiliary equipment,” says Pickett. “Most contractors don’t realize that 6 kilowatts are not available when the lights are running and end up overloading the machine.” Instead, use a generator to power other equipment.
Properly starting the machine is another key to keeping the light tower running correctly. Before starting the machine, make sure all the breakers, switches and lights are turned off. If the
light switches and the breakers are on, the machine is starting under a load. Starting under a load is rough on an engine and decreases engine life.
Before starting the machine, Pickett recommends walking around the light tower to make sure there are no loose items on the engine, generator or the mast and that wire connections to the light fixtures are tight. Most light towers have plug-in wire connections that should be checked before starting the machine.
Other checks to perform before starting the light tower include making sure the fuel tank has not been damaged, testing all belts for proper tensioning and inspecting the battery and connections are in place. Light tower cabling should also be checked every month. When a cable has become frayed or damaged, it needs to be replaced.
The same goes for shutting down the light tower. Turn off all lights, switches and breakers before turning the engine off. Let the engine run and cool for two or three minutes after the lights and breakers are off.
The Speed of Light
Before towing the machine, do a quick inspection of the light tower to make sure it is in condition to be transported. Check the lug nuts on the wheels to make sure they are tight. The undercarriage should be inspected to make sure there is nothing broken and that nothing is under the machine that might damage it. Harness wiring should not be damaged.
“Use the proper size hitch and be sure to use the safety chains,” says Wright. “Don’t exceed the speed limit rating on the machine. The instructions show how to put the safety chains on and show the recommended speed.”
For example, the maximum speed an Ingersoll Rand light tower can be towed is 65 miles per hour. And never tow the machine with the mast extended, even if it is just to a different location on the jobsite. The machine is not designed to be transported with the mast extended and doing so may cause damage.
When you finally reach the jobsite, there are three things to remember when it comes to raising the mast: use the outriggers; keep the machine level; and be aware of wind speed. The outriggers should be fully extended and locked, and the machine should be level before raising and lowering the mast. Some light towers, such as the Ingersoll Rand LightSource light towers, have a bubble level on an enclosure near the mast to help contractors make sure the machine is level.
All light towers have a wind rating — Ingersoll Rand models can be used in winds up to 65 miles per hour. Usually the light tower will not be used in high winds, but any time a contractor suspects that winds are near 65 miles an hour, the mast should be lowered as a precaution.
Turing Out the Lights
When it comes time to store the machine for an extended period, such as over the winter, the mast should be lowered and locked in place. Coolant is the most important thing to check on the machine.
“Add diesel fuel conditioner to the fuel and make sure the coolant can protect the engine,” says Wright. “Test the coolant. A machine with weak coolant will freeze the engine block over the winter.”
When a new light tower leaves the factory, it typically has a 50-50 solution of anti-freeze and water. This mix will protect the engine down to minus 34 degrees Fahrenheit. However, osmosis and any leaks that may have occurred sometimes cause contractors to add more water to the machine. This is why the coolant should be inspected, to make sure there is enough of a balance to keep the water from freezing. It’s also suggested that any ground wire be removed from the battery when storing the machine for the winter.
Not a lot of work is required to keep a light tower maintained. By regularly performing required maintenance and operating the machine safely and in a fashion recommended by the manufacturer, you can expect a long life from a light tower.
“If maintained properly, 22,000 to 24,000 hours on a light tower is possible,” says Pickett. “I’ve seen some machines get into the 30,000-hour range.” A well-maintained machine will keep the lights running and keep the work continuing through the night.
Eric Morse is a technical writer for Two Rivers, Des Moines, Iowa.