Commercial & Industrial HVAC Maintenance

Proper seasonal maintenance is essential for commercial HVAC systems to operate efficiently year-round. Following a structured maintenance schedule helps prevent costly breakdowns, extends equipment life, and ensures optimal performance during peak demand periods.

Spring Maintenance (Before Cooling Season)

• Check and clean condenser coils

  Remove debris and wash coils to ensure optimal heat transfer. Dirty condenser coils can reduce efficiency by up to 30%.
• Inspect refrigerant levels and check for leaks

  Low refrigerant levels indicate a leak that needs immediate attention to prevent compressor damage.
• Test and calibrate cooling controls

  Ensure thermostats, economizers, and building automation systems are accurately controlling cooling equipment.
• Check cooling tower components

  Inspect fill, spray nozzles, basin, and drift eliminators. Clean as needed and check water treatment systems.

Fall Maintenance (Before Heating Season)

• Inspect heat exchangers

  Check for cracks or corrosion that could lead to carbon monoxide leaks. This is a critical safety inspection.
• Test ignition system and burners

  Clean burners and verify proper ignition sequence to ensure reliable operation during cold weather.
• Check steam traps (if applicable)

  Failed steam traps waste energy and reduce heating efficiency. Replace any defective traps.
• Inspect boiler components

  Check safety controls, water level indicators, pressure gauges, and perform a combustion analysis.

Quarterly Maintenance Tasks

Clean HVAC coils are essential for efficient heat transfer and system performance. Regular coil cleaning can reduce energy consumption by 10-25% and help maintain optimal indoor air quality in commercial buildings.

Why Coil Cleaning Is Critical

Dirty coils cause the following issues:

• Reduced heat transfer efficiency
• Increased energy consumption
• Higher operating costs
• Shortened equipment lifespan
• Decreased indoor air quality
• Potential for mold and bacterial growth

Condenser Coil Cleaning Procedure

1. Preparation and Inspection

   Turn off power to the unit and visually inspect coils for damage. Remove loose debris with a soft brush or vacuum. For rooftop units, check for bird nests or other large obstructions.

2. Apply Coil Cleaner

   Use a commercial-grade alkaline coil cleaner appropriate for condenser coils. Apply from the inside out when possible to push dirt outward. Allow cleaner to dwell according to manufacturer's recommendations (typically 5-15 minutes).

3. Rinse Thoroughly

   Use a low to medium pressure water spray (under 600 psi) to rinse from the inside out. Excessive pressure can damage coil fins. Rinse thoroughly to remove all cleaning solution.

4. Straighten Fins

   Inspect for bent fins and repair with a fin comb of the correct spacing (8-14 fins per inch is common for condenser coils).

5. Final Inspection

   Verify all debris has been removed and coils are clean. Check surrounding areas for cleanliness. Allow coils to dry completely before restoring power.

Evaporator Coil Cleaning Procedure

1. Access and Assess

   Turn off power to the AHU. Remove access panels to expose the evaporator coil. Inspect for visible mold, dirt accumulation, and fin condition.

2. Dry Cleaning

   Use a soft brush or vacuum with HEPA filter to remove loose debris. Work in the direction of the fins to avoid damage. For commercial AHUs, compressed air can be used carefully from the exit air side.

3. Apply No-Rinse Foaming Cleaner

   For light cleaning, use a self-rinsing evaporator coil cleaner. These products foam and then drain with condensate, breaking down dirt without requiring water rinsing.

4. Deep Cleaning (When Necessary)

   For heavily soiled coils, use an appropriate coil cleaner and a portable pressure sprayer. Protect surrounding areas from runoff. Create a temporary drain path to collect the rinse water.

5. Apply Mold Inhibitor

   After cleaning, apply an EPA-registered antimicrobial treatment designed for HVAC systems to prevent mold growth.

6. Reassemble and Test

   Replace all access panels, restore power, and verify proper operation. Check for even airflow across the coil surface.

Recommended Cleaning Frequency

Proper air filtration is essential for maintaining indoor air quality and protecting HVAC equipment. Commercial HVAC systems require a methodical approach to filter selection, monitoring, and replacement based on specific facility needs and air quality requirements.

Understanding Filter Efficiency Ratings

Commercial filter ratings generally use the MERV (Minimum Efficiency Reporting Value) scale:

Filter Replacement Schedule

The following replacement schedule serves as a general guideline. Use pressure differential measurements across filters for more precise timing.

Filter Replacement Procedure

1. Prepare and Assess

   Turn off the air handler. Gather replacement filters, disposal bags, and PPE (gloves, mask if needed). Inspect the existing filter condition to inform future replacement timing.

2. Remove Old Filters

   Carefully remove old filters to avoid dislodging collected particulates. Place them immediately in disposal bags to prevent contamination of the surroundings.

3. Inspect Filter Housing

   Check filter tracks, gaskets, and holding frames for damage. Clean the filter housing area using a HEPA vacuum. Repair any bypass issues that would allow air to circumvent filters.

4. Install New Filters

   Verify the new filters are the correct size and MERV rating. Note the airflow direction arrows on the filter frame and install accordingly. Ensure filters fit snugly with no gaps.

5. Document and Monitor

   Label new filters with installation date. Record the replacement in the maintenance log. Reset filter monitoring systems if applicable. Consider taking before/after static pressure readings.

Monitoring Filter Performance

For optimal performance, implement these monitoring practices:

• Install pressure differential gauges

  Measure the pressure drop across filter banks to objectively determine when replacement is needed. Replace filters when pressure drop exceeds manufacturer recommendations.
• Implement filter check protocols

  Create a systematic process for regular visual inspections, especially during seasons with higher particulate loads.
• Monitor system performance

  Track airflow rates, static pressure, and energy consumption. Significant changes may indicate filter loading.

Centrifugal chillers are critical components in large commercial and industrial cooling systems. Proper maintenance of these sophisticated machines ensures optimal efficiency, extends equipment life, and prevents costly failures.

Oil Maintenance Procedures

Proper oil management is critical for bearing lubrication and compressor health in centrifugal chillers.

• Regular Oil Analysis

  Perform quarterly oil analysis to test for moisture content, acidity, metal particles, and viscosity. This helps identify bearing wear, moisture contamination, or refrigerant dilution before damage occurs.
• Oil Filter Replacement

  Replace oil filters annually or when pressure differential across the filter exceeds manufacturer specifications. Inspect the removed filter for metal particles that may indicate bearing wear.
• Oil Change Schedule

  Change oil every 3-5 years or sooner if oil analysis indicates contamination or degradation. Some newer chillers with synthetic oils may extend this interval based on oil analysis results.

Oil Change Procedure

1. Preparation

   Shut down the chiller and allow it to cool. Prepare oil collection containers. Have replacement oil and filters on hand. Verify the oil type matches manufacturer specifications.

2. Drain Used Oil

   Open the oil drain valve and drain oil into appropriate containers. Allow sufficient time for complete drainage. Some chillers may require an oil pump for complete removal.

3. Replace Oil Filter

   Remove and replace the oil filter. Inspect the old filter for metal particles or other contaminants that might indicate internal issues.

4. Clean Oil System Components

   Where accessible, clean the oil reservoir, oil cooler, and oil lines. Flushing the system may be necessary if heavy contamination is present.

5. Fill with New Oil

   Add new oil to the correct level according to manufacturer specifications. Use only OEM-approved oil types. Avoid mixing different oil types.

6. System Check

   Run the oil pump to circulate oil and check for proper pressure and flow. Check for leaks around filter housing and other connections.

Purge System Maintenance

Low-pressure centrifugal chillers require effective purge systems to remove non-condensable gases that reduce efficiency and increase operating costs.

• Purge Filter Maintenance

  Replace or clean purge filters quarterly or when pressure drop indicates clogging. Dirty filters reduce purge efficiency and can cause the system to run longer than necessary.
• Purge Pump Inspection

  Check purge pump operation monthly. Verify proper current draw and cooling. Replace seals and bearings as needed during annual maintenance.
• Monitor Purge Runtime

  Excessive purge operation may indicate air leaks into the refrigerant system. Track purge runtime and investigate increases that could indicate developing leaks.

Tube Cleaning Schedule and Procedure

Heat transfer efficiency in centrifugal chillers depends on clean tubes in both the evaporator and condenser barrels.

Tube Cleaning Procedure

1. Preparation and Isolation

   Shut down and lock out the chiller. Isolate water circuits by closing valves. Drain water from the barrel being cleaned. Remove end water box covers and inspect for scale, corrosion, or debris.

2. Mechanical Cleaning

   Use appropriate tube brushes attached to a rod or drill. Select brush size and material based on tube material and fouling type. Push and pull brushes through each tube several times to remove deposits.

3. Water Flushing

   After mechanical cleaning, flush tubes with clean water to remove dislodged debris. For heavily fouled systems, high-pressure water jetting may be necessary.

4. Inspection

   Use a borescope to inspect cleaned tubes for remaining deposits, damage, or erosion. Document any tubes showing signs of damage or excessive wear.

5. Chemical Cleaning (if necessary)

   For stubborn scale or biological fouling, chemical cleaning may be required. Use appropriate cleaners for the tube material and fouling type. Follow all safety procedures for chemical handling.

6. Reassembly

   Replace gaskets or O-rings on water box covers. Reinstall covers and torque bolts to manufacturer specifications. Refill the water system and check for leaks before returning to service.

Eddy Current Testing

Perform eddy current testing every 3-5 years to detect tube wall thinning, pitting, or cracks before they lead to refrigerant/water mixing. This non-destructive testing is critical for older chillers or those with known water quality issues.