Service work is no day at the beach. In fact, at times it can be downright dangerous.

Tom Hickey, for one, has witnessed firsthand the consequences of bad installations and poorly maintained equipment.

“Two guys in this town lost half their faces and needed reconstructive surgery after a stainless steel [filter] lid hit them on the way up,” says the owner of Hickey Custom Pools in Tucson, Ariz. “Exploding filters are one of the biggest dangers we have as technicians.”

There are many “hot spots” around the pool where service technicians are advised to exercise caution. Here industry veterans review four of the most common trouble areas, and offer advice on how to keep potentially dangerous conditions in check.

The filter

Manufacturers over the years have developed better locking mechanisms and internal air bleeds, making the process of relieving air pressure in a filter much safer. However, older filters still must be bled by hand.

Though less common today, the combination of a dirty filter, air leaks in the hydraulics and plugged internal air bleeds can create an explosive situation.

“It almost has to be a perfect storm,” says Steve Bludsworth, owner of All-Pool Service & Supply in Orlando, Fla.

Still, accidents do happen. An exploding filter lid earlier this year resulted in a broken arm for a tech Bludsworth knows in Texas.

So how does one diffuse this potentially dangerous scenario? By eliminating excess air. Air leakcx`s can enter the hydraulics through a number of different sources. Among the most common culprits is the pump, where, for example, an O-ring can become unsealed.

To detect such leaks, try crafting a piece of vinyl tubing into a makeshift stethoscope. While placing one end to your ear, move the opposite end around the suspect area until you detect a hissing sound.

Also, check the hose on a suction-side automatic cleaner for breaches. Any holes or cracks will allow air to flow back into the system.

If air does begin to build up in the filter, take extra caution when releasing it via the external air bleed. Never put your head over the filter or anywhere near the locking mechanism holding the filter together.

“Keep your free hand between the lid and your head,” Hickey advises. “While you may not be totally protected, it’s far better to break an arm than crack open your head.”

Finally, you should routinely monitor the internal air bleed on newer filters to ensure it’s not damaged.

The heater

Heaters are another potential source of danger when they’re improperly installed.

Because of their popularity and design, gas heaters are the most pressing concern.

The solution? Prevent gas buildup. On gas units, leaks tend to occur most often around the unions, says Don Pollard, owner of The Pool Pro in Glendora, Calif., who recommends these parts be checked and replaced as needed.

Gas buildup also may result from a broken heater. If you suspect this is the case, begin by testing the inlet gas pressure while the heater is in use. A drop in static pressure usually means a gas valve is open, and when that occurs, the heater should fire. But if the heater isn’t turning on, the gas is still flooding the unit.

“If there’s flow and the heater still doesn’t fire, you’d better shut that thing off immediately,” Hickey says.

Also note that propane gas is heavier than air, and generally will collect in low spots around the equipment pad.

And while heaters can malfunction at any time, the problem may be traced to simple, poor installation.

“We’ll go behind other people where guys have bypassed the safety features of the heater,” Bludsworth says. “They’ve taken the high-limit or pressure switch out of the loop in order to get the heater to fire. It’s kind of like disconnecting the air bags on your car.”

Remove these safety measures, experts warn, and the heater will fire almost without limitation. The last place you’d want to be, in this instance, is near the equipment pad.

Perhaps the best advice is expect the unexpected. Bludsworth once discovered a gas heater that was retrofitted into a propane gas line. While natural gas operates on low pressure, propane gas uses high pressure. The variance in pressure means there was a significant size difference between the openings of each heater type. As expected, the installation didn’t last long.

“[The heater] was like a flamethrower,” he recalls. “It burned the whole side of the house, and it melted the vinyl siding.”

So use caution: You never know when you may be working behind a hasty builder or inexperienced tech.

The wiring

Though rarely lethal, electrical shock probably is the most common hazard for service techs. It can originate from a range of sources — chewed wires, poor installations, faulty GFCIs and plain bad luck — which often makes identification difficult.

Some situations are nearly impossible to foresee. What’s the answer then?

Recognize bad wiring. A homeowner, or prior technician, may mistakenly connect a hot wire to a ground lug, which would energize the entire pump. Or, hot wires may be hooked up to bond wires, energizing the surrounding yard.

Pool lights can be another source of danger, particularly during installation and testing. Older lights are especially tricky. Case in point: A GFCI may not be present in light niches installed before the 1990s.

With no safety device present, it may be best to simply steer clear of the repair.

“We won’t even touch them,” Bludsworth says. “You have to have an electrician bring the fuse up to code before we change a bulb.”

Finally, if there’s a lighting panel box, make sure it’s a safe distance from the pool. On older pools, these often are installed just beneath a diving board.

The rubber coating that protects the wiring won’t last forever, and heavy rains or splashout can cause big problems.

“Once the rubber seal wears off, water gets into the wiring — which leads to electrocution,” Pollard says.

And that’s why, after so many years in the business, Bludsworth usually refers any unconventional wiring around the pool to a certified electrician.