HVAC Systems

HVAC (Heating, Ventilating and Air Conditioning) systems can become unreliable and costly when not functioning properly. There are many benefits to performing routine maintenance on your HVAC system. Take these important steps to help ensure your HVAC system is as efficient and effective as possible.

Regular HVAC Maintenance

Relative humidity should be monitored in all areas of the building, as an indicator of moisture problems. Moisture problems can occur in commercial buildings when there is uncontrolled airflow between conditioned and un-conditioned spaces within the building or between outside air and conditioned space. Uncontrolled airflow can occur wherever there is a leak or break in the air barrier of the building (around pipes, at wall and roof connection points, etc.). When there is a leak or break in the air barrier, any unbalance in the airflow associated with the HVAC system can result in significant airflow into or out of the conditioned space. When the unbalance creates a lower (negative) pressure in the building than that outside the building, then external un-conditioned air, which can be moisture laden in summer or high humidity conditions, is drawn into the wall or roof cavities where the moisture condenses on surfaces that have been cooled by air conditioning.

  • Check the HVAC system balance regularly to ensure appropriate pressures and airflow.
  • Check HVAC response to thermostats, humidistats, and other control systems regularly.

Here are some common causes of HVAC negative pressure and their possible solutions:

Insufficient return air supply. Common solutions include adjusting dampers or installing vents in walls or doors.

Improper balance of ventilation and exhaust systems. This can apply to the combustion appliance venting, laboratory fume hoods, kitchen exhaust, etc. A common solution here is to add the appropriate air makeup and conditioning measures.

Supply duct leaks. The common solution here could be as simple as taping or sealing joints in ducts.

Monthly HVAC Maintenance

  • Inspect your HVAC air filters monthly, or as recommended in the Operations and Maintenance manual. If you don’t know how to access the filters, refer to the manual for your specific unit.
  • When dust and debris are present, replace the filter with an identical filter as recommended by the manufacturer. If the filter is reusable, be sure it is completely clean and dry before reinstalling. Depending on its size, the equipment may have multiple filters that should be inspected or replaced.
  • Inspect all condensate drains and drain pans monthly, especially if your building must provide cooling most of the year. Refer to the maintenance book when inspecting drains and drain pans.
  • Check drain pans to insure they drain freely, are adequately sloped toward the outlets and that no standing water is present.
  • Make sure drain lines are clean and clear of obstructions.
  • If dirt, algae, or other contaminants are found, the drain line should be flushed and the drain pan carefully cleaned (pour a water-bleach solution down the drain line until it flows freely).
  • Inspect for signs of rust, which could indicate a water problem and need for prompt repair.
  • If the line drains to the outdoors, ensure that drainage travels away from the structure.
  • If the condensate drain is located on the roof, check that the drain is not clogged.
  • Rooftop drains should never drain directly onto the roof or over the side of the building.

Seasonal HVAC Maintenance

  • Condensate drain pan overflows frequently occur the first time the unit is turned on in the spring because dust and dirt have accumulated over the winter months. However, overflows can occur any time the drain becomes plugged to the extent that the condenser removes water from the air faster than the drain line discharges the water.
  • Clean prior to first use with compressed air or by pouring a water-bleach solution down the drain line until it flows freely.
  • A float cutoff switch that will shut down the system if the pan doesn’t drain properly is a great safety feature that can prevent a flood from the overflowing drain pan.
  • Inspect ductwork seasonally for cleanliness, insulation, and tight connections.
  • Fresh air supply ducts must be kept free of debris and, if necessary, filtered at the inlet.
  • Inspect filters and ductwork to ensure adequate fresh air supply.
  • Make immediate repairs at the first sign of condensation or rust. Any rust, condensation, or other signs of moisture on ductwork can be a sign of a serious water management problem.
  • Furnace burners should be inspected at the beginning of each heating season, and regularly throughout the heating months.
  • Visually inspect the flame, which should be blue with a light yellow tip. If the flame is not this color, or, if the heating unit does not ignite promptly, contact an experienced HVAC professional.
  • Regularly check combustion gas exhaust components (chimneys, vents and connective pipes) to ensure proper venting of combustion byproducts.
  • Check the heat exchangers seasonally.
  • Cracked heat exchangers can create health, safety and water management problems. If checking these items is beyond the skills of your maintenance staff, be sure your HVAC professional is experienced in combustion appliance operation and safety.
  • Check for backflow of combustion gasses, carbon monoxide levels and other indicators of improper heating system performance.

Annual HVAC Maintenance

  • All air coils should be inspected annually, at minimum, to confirm that equipment is operating at maximum capacity.
  • Follow the manufacturer’s instructions to obtain access to the air coils.
  • Coils should be cleaned of dust and debris by careful brushing or vacuuming, to avoid damaging the coil fins.
  • Keep outdoor condensing units clean from grass clippings and other debris.
  • Condenser units must remain level in order for water to drain properly.

Hiring an HVAC Professional

Many modern HVAC systems are complex and require the skills of a trained professional. If your on-site maintenance staff is not fully familiar with HVAC systems, hire a professional before you are faced with a system failure or water management crisis.

When performing general maintenance on your HVAC system, it is important to choose a reputable specialist. The Institute for Business & Home Safety (IBHS) offers the following guidelines to help you make a sound decision:

  • Hire a company that has extensive experience with your type of HVAC system.
  • Request references to ensure past and current clients are happy with their work.
  • Ask to see proof of a license.
  • Require proof of insurance.
  • Check with the Better Business Bureau to ensure they have a clean reputation.

If your HVAC system needs maintenance or repair following a major disaster, be alert to the potential for fraud. The Federal Emergency Management Agency (FEMA) suggests these guidelines to help avoid being taken:

  • Use local contractors, preferably one with whom you have a prior relationship. If they are not available, ask for recommendations. Consult with several contractors in-person prior to making a choice.
  • Get all estimates in writing and ask about fees before making an appointment. All estimates should include specifics about the work the contractors are expected to perform.
  • Ask for references and follow up with prior customers. Would they hire the contractor again?
  • Ask for proof of insurance. If a contractor is not insured to perform the work, you may be liable if an accident happens on your property.
  • Once you are satisfied with an estimate, ask for a written contract that includes all work to be performed, costs and the payment schedule. Never sign a blank or incomplete contract. For large jobs, an attorney may need to review documents before anything is signed. Get a copy of the signed contract.
  • Ask for a written guarantee, if it’s not already in the contract. Any guarantee should include what is covered, who is responsible for fulfillment and a validation date.
  • Pay only when the work is finished and you are satisfied. Reputable contractors will not threaten you or pressure you to sign anything if the job is not complete or you are not happy with the quality of the work.

Staying on top of routine maintenance goes a long way toward protecting your equipment and your business from the unexpected. For more information about American Family Insurance’s Safety Consulting Services, visit our Loss Control Resource Center.

DISCLAIMER — These recommendations were developed using generally accepted safety standards. Compliance with these recommendations is not a guarantee that you will be in conformance with any building code, federal or state regulation regarding safety or fire. Compliance with these recommendations does not ensure the absolute safety of your operation or place of business. It is the property owner’s duty to warn any tenants or occupants of the property of the safety hazards that may exist. Source: Insurance Institute for Business & Home Safety (IBHS). www.DisasterSafety.org

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Related Topics: Employee Safety , Protecting Your Business