Buildings that are improperly heated or cooled can result in a variety of issues, including decreased staff productivity and computer faults. Commercial RTU NYC systems that fail mechanically can cause thousands of dollars in damage. Proper maintenance can prevent these events, as well as the bulk of repair calls. Minor changes that indicate the need for a repair call are difficult to see or hear because packaged units are typically positioned on building rooftops. (When you’re out of sight, you’re out of mind.) In addition, well-maintained equipment can reduce overall annual operating and repair expenditures. The maintenance practices listed below will keep your business HVAC system in good working order.
Air filters should be inspected every 3 to 4 weeks and replaced or cleaned if necessary.
- Clogged filters obstruct normal air movement and diminish a system’s efficiency. When normal air movement is hindered, dirt may be carried directly into the evaporator coil, reducing the coil’s heat-absorbing ability.
- Keeping the filter clean can reduce the energy usage of your air conditioner by 5%–15%. If there isn’t enough air over the indoor coil in cooling mode, the coil temperature drops. When the temperature dips below freezing, ice accumulates on the coil, reducing airflow and coil temperature even further. A compressor is a pump that is used to transport vapor. As the airflow through the indoor coil decreases, the heat extracted from the air flowing over the coil is insufficient to evaporate the liquid refrigerant. As a result, instead of vapor, the compressor receives liquid refrigerant, which is referred to as “liquid slugging.”
The cylinder pressure of rooftop unit installation exceeds the design limitations because liquids are not compressible. Valves, pistons, and other internal components are ruined as a result. The unit simply needed a filter repair at first, but now it requires a new compressor. Low airflow causes the heat ex-changer to overheat in heating mode. The heat ex-changer oxidizes at higher temperatures, reducing its life lifetime or cracking and breaking. In either instance, replacing air filters on a regular basis is preferable to replacing a heat ex-changer.
Examine the motor and blower wheel housing.
- Because they draw fresh air into buildings, the blower wheel housing and motor are essential components of the air handling system. Blower wheels that are dirty can reduce airflow, causing the coils to freeze and the compressor to fail, as well as raise the cost of operating the machine. Blower wheels that are dirty might become imbalanced, broken, and cause the engine to overheat. Increased sound when the machine is running might sometimes indicate this.
Although good filtration keeps debris out of the fan, an annual visual inspection is still recommended. Fan efficiency will decline if impeller blades are coated with dirt.
Inspect belts, pulleys, and bearings for wear and tear, and oil motors and bearings as necessary.
- Check for cracks, fraying, and adequate tension on belts. Belts that are too loose can cause sliding, resulting in inconsistent cooling and heating. Excessive tension might put the motor and bearings under a lot of strain. Due to belt slippage, worn drive belts wear a groove in the pulleys, causing the fresh belt to be destroyed in a short period of time. Bearings that are not properly greased will overheat and seize. The bearings break down, and the blower wheel, shaft, and housing are all destroyed.
Replace the drive belt every year
- Blower belts are a common wear and tear item that should be replaced every year. Extensive machine operation may demand further belt replacement on occasion.
- If the finned surfaces of the outside coils are contaminated with dirt, their ability to transfer heat is impaired, and airflow through the condenser coil is reduced. The operating temperatures and pressures of the unit rise when the device’s ability to transport heat is compromised. Because of the lower heat transmission capability, a unit may shut down. The unit shuts down when the operating temperatures and pressures inside it reach the manufacturer’s safe limit. If the unit does not exceed the manufacturer’s restrictions to the point of shutting down, it will continue to operate at a lower capacity and efficiency, as well as having a higher rate of wear due to the increased workload. Examine the indoor drain pan as well as the condensate drain lines.
- If the system has an auxiliary drain pan and line, inspect them as well. If necessary, the service should include cleaning. A unit’s ability to reduce humidity is hampered by clogged drain channels.
Annually inspect the economizer
- Conduct an annual cycle inspection to ensure the actuator, dampers, and temperature sensors are in good working order. Check the dampers and ventilation settings throughout the ducting system. When the outside air is cool, the amount of outside air is raised, and the amount of re-circulated air is reduced to maintain the required supply air temperature. This way, refrigeration-based cooling is avoided entirely at certain periods of the year, and especially at night. Examine all electrical connections, wiring, and relay points.
- It’s critical to double-check the electrical connections for both high and low voltage. A faulty electrical connection can cause serious problems as well as pose a safety risk. The inspection will look for corroded or frayed wires, as well as unsecured wiring or electrical connections. In a commercial structure, a faulty electrical connection could cause a fire.
Check for voltage imbalances
- Unbalanced voltages in a 3-phase system will cause electrical equipment, particularly motors and their controls, to fail. The difference between the highest and lowest voltages should generally not be more than 4% of the lowest voltage. Overheating of components, particularly motors, and intermittent shutdown of motor controllers may occur because of greater imbalances. Unbalanced voltage motors will overheat, and many overload relays will not detect the overheating. Furthermore, many solid-state motor controllers and inverters contain components that are particularly vulnerable to voltage imbalances.
Conduct amperage inspections on a yearly basis.
- Overloading could be a mechanical problem, such as worn bearings or rods, if the equipment is drawing more than 10% of its rated capacity. Excessive suction pressures can also create high amperage, indicating a refrigeration problem.
- During each maintenance visit, conduct a visual inspection. Loose parts can lead to excessive wear, equipment failure, and potentially costly damage to the device. Check for chips or cracks in fan blades that could cause noise or vibration. Flue gas routes, burners, heat ex-changers, coupling boxes, and inducer assembly should all be inspected.
- By far the most important component of your unit is the heat ex-changer. A major health and safety issue could arise if the heat ex-changer rusts or cracks. Combustible byproducts could potentially leak into the building’s air supply through these fractures. This could lead to serious sickness and, in the worst-case scenario, death. It’s conceivable that you’ll need to disassemble some of the unit to investigate the heat ex-changer more completely. Examine the inducer motor for correct operation, as well as the inducer wheel for excessive corrosion, missing blades, and balance.
- Ignition issues include popping, roaring noises, smoke, shaking, and flame rollout (gas heat only). The absence of a yellow color in the flames could suggest a problem with that burner. Inspection of these components is required to ensure the safe and efficient operation of your equipment. A gas leak test should also be performed.
Seasonally, conduct an overall operational check.
- This includes monitoring and adjusting the refrigerant charge as well as testing the gas pressure of the unit according to the manufacturer’s instructions. After you’ve completed all your checks, you should make any necessary repairs or adjustments. Now that we’ve given you an outline of a comprehensive maintenance inspection, we must remind you to double-check that all panels are properly fastened in place after performing maintenance and/or repair.
Using hand tools to remove and replace these little screws can be tedious, which is why after a few repair calls, many panels only have one or two screws left in place. However, unsecured panels result in a leaking unit, which means important chilled air is leaking onto the roof. Don’t over tighten the screws or they’ll peel. To replace missing screws, technicians should maintain a bag of screws on hand, including bigger screws for stripped holes. When you consider all the potential repair/replacement costs, the cost of a regular maintenance agreement is clearly more advantageous.