Chiller Maintenance Checklist for South Florida Buildings

A chiller in Ohio gets a winter off. A chiller in Fort Lauderdale does not. Ours run ten, eleven, sometimes twelve months a year, in high humidity, with cooling towers pulling in salt and dust from the air. That is why maintenance schedules written for northern climates do not fit here. You need to do more of it, and you need to do it on a calendar that does not assume a long shutdown season.

This is the checklist we use for water cooled chillers in commercial buildings across Broward, Miami Dade and Palm Beach. It is not a substitute for the manufacturer's manual, and it lines up with the approach in ASHRAE Standard 180, which covers inspection and maintenance of commercial HVAC systems. Think of it as the version a building engineer can actually work from.

Daily: keep a log, and read it

The single best maintenance habit is a daily log. Write down, or have the building automation system record:

• Chilled water supply and return temperatures

• Condenser water supply and return temperatures

• Evaporator and condenser refrigerant pressures or saturation temperatures

• Approach temperatures on the evaporator and condenser

• Compressor amps or percent load

• Oil pressure and oil temperature

The numbers by themselves do not mean much. The trend is what matters. If the condenser approach creeps up a degree or two over a few months, the tubes are fouling. If the evaporator approach rises, you may be low on refrigerant or have a fouled evaporator. A log turns a surprise breakdown into a planned repair.

Monthly

Walk the plant. Look and listen. Check for oil leaks, refrigerant leak signs, unusual vibration and noise. Look at the sight glasses. Verify the flow switches work, because a chiller that loses water flow without tripping can freeze an evaporator tube and that is an expensive day.

Check the cooling tower too. In South Florida, the tower is where most of the trouble starts. Look at the basin, the fill and the drift eliminators. Confirm the water treatment system is feeding chemicals and the conductivity controller is bleeding off. Clean strainers.

Inspect pumps and motors. Bearings, couplings, seals and amps. A pump that is drawing more current than last month is telling you something.

Quarterly

Pull an oil sample and send it for analysis. Oil analysis shows wear metals, moisture and acid before they cause a failure. It is cheap compared to a compressor.

Check refrigerant charge and run a leak check. Larger systems are subject to EPA leak repair rules under Section 608 of the Clean Air Act, and newer rules under the AIM Act extend leak management to many HFC systems. Your technician should know which rules apply to your equipment and keep the required records. Either way, a leaking chiller costs money every day it runs.

Verify controls and safeties: low pressure cutout, high pressure cutout, freeze protection, motor overloads. Calibrate temperature sensors. A sensor that reads two degrees off can waste a lot of energy or cause nuisance trips.

Annually

Clean the condenser tubes. In South Florida, many buildings should do this at least once a year, and some plants with hard water or tower problems need it more often. Fouled tubes drive up head pressure and energy use. While the heads are off, inspect the tube sheets and gaskets.

Eddy current test the tubes on a regular cycle, often every few years depending on the age of the machine and what earlier tests showed. Eddy current testing finds thinning and pitting before a tube leaks. A tube leak in a water cooled chiller can put water into the refrigerant circuit, which turns a routine repair into a major one.

Inspect the evaporator. Closed chilled water loops stay cleaner than condenser loops, but they still need water treatment and periodic inspection.

Check the motor. Megger test the windings, inspect the starter or variable frequency drive, tighten electrical connections and look for heat damage. An infrared scan of the electrical gear feeding the chiller is a good idea while you are at it.

Do a full controls review. Check setpoints, reset schedules, staging and the interface with the building automation system. A lot of plants are running the same setpoints someone typed in years ago.

Cooling tower and water treatment

We put this in its own section because it is the number one source of chiller problems we see. A cooling tower in South Florida is a giant air scrubber. It catches pollen, dust, leaves and salt, and the warm water is a perfect home for biological growth.

Good water treatment controls scale, corrosion and biological growth. Scale on condenser tubes acts like insulation. Corrosion eats tubes and piping. Biofilm reduces heat transfer and can harbor Legionella. ASHRAE Standard 188 sets out how building owners should manage that risk with a water management program, and many owners follow the CDC's toolkit for developing one. Your water treatment vendor, your mechanical contractor and your building engineer should all be working from the same plan.

Clean the tower basin and inspect the fill at least once a year. Many buildings do it twice. Check fan blades, gearboxes or belts, and motor bearings. Look for leaks and damaged casing.

Seasonal planning for hurricane season

Before June 1, make sure the chiller plant can come back after a power loss. Will the chillers restart automatically after a generator transfer, or does someone have to reset them? Does the building have a plan for securing tower components and rooftop equipment? After a storm, debris in the tower and damage to fans and fill are common. Inspect before you restart.

What we see go wrong most often

Most of the chiller failures we get called for were not sudden. The condenser approach had been creeping up for months. The oil analysis was never done. The cooling tower treatment pump had stopped working and nobody noticed. The flow switch had been jumpered out. These are not exotic problems. They are maintenance problems.

If you have a chiller plant and you do not have a log, start one this week. If you have a log and nobody reads it, that is the next step.

Need help with your chiller plant?

We maintain and repair chillers and cooling towers for commercial buildings across South Florida. Read more about our chiller services, or call 954.577.7923 and request service.