SPX Closed Circuit Cooling Tower Troubleshooting: A Comprehensive Guide
There's a certain confidence that comes with owning SPX cooling equipment. Whether it's a Marley, an Aquatower, or any of the other brands under the SPX Cooling Technologies umbrella, you're working with gear that has over a century of engineering behind it . These towers are built to last—I've personally seen Marley units from the 1980s still running strong with proper maintenance .
But let's be honest: even the best equipment has bad days. Maybe you've noticed your outlet temperatures creeping up when they should be steady. Perhaps there's a new rumble that wasn't there last week. Or maybe you're just seeing a persistent mist blowing off the top that's costing you water and money.
Whatever brought you here, you're in the right place. This guide is your field manual for SPX closed circuit cooling tower troubleshooting. We're going to walk through the most common problems, figure out what they mean, and get your tower back to peak performance. No corporate speak, no fluff—just practical advice from someone who's been in the trenches.
Safety First: The Golden Rule Before Troubleshooting
Before we go anywhere near that tower, we need to have a serious conversation about safety. SPX themselves hammer this point home in every manual they publish, and for good reason .
Lockout/tagout is non-negotiable. Always make certain that mechanical equipment is inoperable during periods of maintenance—or during any situation of possible endangerment to personnel . If your electrical system has a disconnect switch, lock it out until the period of exposure to injury is over.
Here's your pre-work checklist:
- Disconnect power to the fan motor and pump motor
- Lock and tag the disconnect switches
- Wear appropriate PPE: gloves, safety glasses, and boots with good grip
- Use proper ladders—the top of the tower is not a working surface
- Be aware of fall hazards and use fall protection where appropriate
Got it? Good. Let's dig in.
Reading the Signs: What's Your Tower Telling You?
Here's the thing about cooling towers: they're constantly communicating with you. You just need to learn the language. Before you grab any tools, stand there for a minute and observe.
Is the outlet temperature climbing? That's a heat transfer issue. Hearing a rhythmic thumping? That's mechanical. Seeing a constant mist blowing away? That's a drift problem. Define the symptom first, and you're already halfway to the cure.
Problem #1: Poor Cooling Performance (High Outlet Temperatures)
This is the big one. Your process is heating up, and your SPX tower isn't keeping up. When cooling efficiency drops, the culprit is almost always in the spray water, the airflow, or the coil itself.
The Spray Water System: Is Your Coil Getting Proper Coverage?
Pop open that access door and look at what's happening inside. You should see a nice, even curtain of water covering the entire coil. If you see dry spots or uneven streams, you've got distribution problems.
Nozzle Blockages and Distribution Issues
Those spray nozzles are designed to distribute water evenly, but they're magnets for sediment, scale, and biological growth . When they clog, you get dry patches on the coil, and heat transfer plummets.
Solution: Inspect the spray system for proper operation and correct as necessary . Remove the nozzles and clean them thoroughly. You can soak them in a mild descaling solution and flush them with clean water.
Spray Pump and Strainer Problems
Check the suction strainer on your spray pump. If it's clogged, your pump is starving, and your spray water flow drops. Clean that strainer regularly—it's a simple task that prevents major headaches.
Also, verify the pump is actually moving water. If you're seeing low flow, you might have a pump issue. SPX notes that overpumping—exceeding the design water flow rate—can actually hurt performance too .
Airflow Restrictions: Can Your SPX Tower Breathe?
Your tower needs massive amounts of air to create that evaporative cooling effect. If it can't breathe, it can't cool.
Fan and Drive System Performance
Take a look at those fan blades. Are they clean? Do they all have the same pitch? SPX emphasizes that all blades must be pitched the same . If the pitch varies, you're losing efficiency and potentially creating vibration issues.
Also check motor current and voltage to be sure you're getting the correct power to the fan . If the fan isn't pulling enough air, you may need to repitch the blades.
Clogged Louvers and Obstructions
Walk around the base. Those inlet louvers are designed to let air in while keeping debris out. But over time, they become catch-alls for leaves, plastic bags, and general industrial flotsam. If they're clogged, your tower is suffocating.
Check to see if nearby structures or enclosing walls are obstructing normal airflow to the tower . Sometimes recirculation of discharge air—where hot exhaust gets pulled back into the intake—can kill performance.
Heat Exchanger Coil Scaling and Fouling
Take a good look at that heat exchange coil. This is the heart of your SPX closed circuit tower. Does it look crusty? Like it's been dipped in a mineral bath? That's scale—calcium and other mineral deposits from the spray water .
This acts like insulation on your coil. You're trying to reject heat through a blanket of rock. Scale formation happens when there's insufficient blowdown or a water treatment deficiency .
Solution: Consult a competent water treatment specialist . For existing scale, you may need a professional chemical clean. Prevention is everything here—maintain proper blowdown and water chemistry.
Problem #2: Unusual Noises and Excessive Vibration
If your SPX tower sounds like it's trying to become an airplane, you've got mechanical problems. SPX troubleshooting guides are full of solutions for noise and vibration issues .
Fan and Blade-Related Issues
Blade Rubbing Inside Fan Cylinder
If you hear a scraping or thumping sound, the fan blade might be hitting the inside of the fan cylinder. This is bad news—it can destroy blades and damage the cylinder.
Solution: Adjust the cylinder to provide proper blade tip clearance .
Deposit Buildup on Blades
Over time, fan blades accumulate dust, pollen, and grime. This buildup changes the aerodynamics and, more importantly, throws the fan out of balance. An unbalanced fan creates vibration that travels through the entire drive system.
Solution: Clean off deposit buildup on blades . It's amazing how much smoothness returns with clean blades.
Geareducer (Gearbox) Problems
The Geareducer is the heart of your SPX tower's drive system. When it talks, you'd better listen.
Geareducer Noise Diagnosis
New gearboxes can sometimes be noisy during the first week of operation—this may be normal break-in noise . But if the noise persists, you've got problems.
Grinding or rumbling usually indicates bearing wear. Gear noise might mean incorrect tooth engagement or badly worn gears. If you hear knocking, check for broken or damaged teeth .
Oil Level and Quality Checks
Low oil is a death sentence for a gearbox. If the Geareducer is noisy, try draining, flushing, and refilling with fresh oil . Sometimes contaminated or degraded oil is the culprit.
Driveshaft and Coupling Issues
Unusual fan drive vibration can come from an unbalanced driveshaft or worn couplings. SPX recommends making sure the motor and Geareducer shafts are in proper alignment and that "match marks" are properly matched .
Solution: Rebalance the driveshaft by adding or removing weights from balancing cap screws. Repair or replace worn couplings .
Problem #3: Motor and Electrical Problems
Electrical issues can be frustrating because they're not always visible. But SPX troubleshooting guides give us a solid roadmap .
Motor Won't Start or Reaches Speed Slowly
If your motor drags or takes forever to come up to speed, you might have low voltage at the motor terminals because of line drop .
Solution: Check the transformer and setting of taps. You may need higher voltage on transformer terminals. In some cases, increasing wire size or reducing load inertia helps .
Also check for broken rotor bars—look for cracks near the rings. A new rotor may be required .
Wrong Motor Rotation Direction
This is embarrassingly common. If the fan is turning the wrong way, you'll get almost no airflow.
Solution: Switch any two of the three motor leads . It's that simple—but you'd be surprised how often this gets overlooked.
Problem #4: Water Leaks and Excessive Drift
Finding water where it shouldn't be is never good. Let's track down the source.
Basin Leaks and Float Valve Malfunctions
Check the cold water basin and all connection points. Sometimes a leak is just a loose drain plug or a failed sealant bead. More often, water level problems come from the float valve.
Solution: Check the float valve periodically for proper operation and proper water level . If the valve is stuck or misadjusted, you'll either run the basin dry or overflow constantly.
Coil Leaks: The Serious Scenario
If you see a steady drip from the coil itself, that's a pinhole leak. This is serious business. Coil leaks usually come from corrosion—either from the inside (poor water treatment in your closed loop) or from the outside (constant spray water attack).
Solution: Small pinholes can sometimes be repaired, but it's tricky. You must drain and isolate the coil first. If the coil is old and corroded, replacement is the only safe option.
Drift Eliminator Failure (Visible Mist)
Is there a constant mist blowing off the top of your tower, even on calm days? That's "drift," and it means your drift eliminators aren't doing their job .
Causes: Faulty drift elimination, damaged eliminators, or eliminators that aren't properly installed.
Solution: Check to see that the eliminators are clean, free of debris, and installed correctly . Clean if necessary. Replace damaged or worn out components .
Problem #5: Water Quality Issues
Water chemistry problems are silent performance killers. You might not notice them until significant damage is done.
Scale Formation and Insufficient Blowdown
Scale or foreign substances in the circulating water system usually come from insufficient blowdown or water treatment deficiency .
Solution: See the water treatment section of your manual. Consult a competent water treating specialist . Blowdown—the continuous discharge of a portion of circulating water—is essential to control the concentration of contaminants .
Biological Growth and Contamination
SPX takes biological contamination seriously—and you should too. Any evaporative cooling tower must be thoroughly cleaned regularly to minimize the growth of bacteria, including Legionella Pneumophila .
Solution: Inspect for bacterial growth at least once a week during operating season . At a minimum, clean and disinfect with biocides twice a year. Systems with biofouling or positive cultures of legionella may require additional cleaning .
The Freeze Factor: Winter Protection
If you're in a cold climate, winter can wreck your tower if you're not careful. Water expands when it freezes, and it will split coils and pipes like an axe splits wood.
When the system is to be shut down for an extended period, SPX recommends draining the entire system—cooling tower, system piping, heat exchangers, and so on . Leave the basin drains open.
During shutdown, clean the tower and make any necessary repairs. Pay particular attention to mechanical equipment supports .
Preventive Maintenance: Your Best Troubleshooting Tool
Here's the truth: the best troubleshooting is the kind you never have to do because you caught problems early. SPX offers comprehensive service and maintenance packages for a reason .
Weekly and Monthly Checks
- Weekly visual inspection during operating season
- Check for bacterial growth and general operating conditions
- Inspect louvers, drift eliminators, and basin trash screens—remove any debris or scale
- Check belt tension every two to three weeks during peak season
- Check makeup float valve for proper operation and water level
- Check blowdown for continuous water discharge during operation
Annual Deep Maintenance
- Drain and clean cold water basin and suction screen
- Lubricate motor according to manufacturer's instructions
- Check all bolts in fan and mechanical equipment region—refer to component manuals for torque values
- Inspect tower thoroughly—check structural bolted connections and tighten as required
- Inspect metal surfaces for evidence of needing protective coating
- Clean and disinfect with biocides (minimum twice yearly)
Conclusion: Keeping Your SPX Tower Running Strong
Look, troubleshooting an SPX closed circuit cooling tower isn't about magic or luck. It's about paying attention, following a logical process, and doing the little things before they become big things.
SPX Cooling Technologies brings over a century of experience to their equipment . These towers are designed to provide years of reliable service when properly maintained. But they need you to be their eyes and ears.
Keep that spray water system clean. Maintain proper water chemistry. Listen for unusual noises. Address small problems before they escalate. And for heaven's sake, follow the maintenance schedule.
Your SPX tower is built to last. With a little love and attention, it will keep your process cool for decades to come. Now go give that tower some attention—it's earned it.
