#construction Archives - United CoolAir

October 14, 2020 by Matt Hanson

Compressor Failure and the Effects on Warranty

Identifying why compressor failure is subject to many variables and is important to understanding warranty implications. Although compressors fail for a multitude of reasons, poor installation and maintenance are the most common causes. However, for the vast majority of compressors returned for claims, rarely is it due to a defect in the manufacturer supplied part.

Determining why a compressor has failed is a challenge for contractors of light commercial cooling systems. The mere fact that installation and maintenance procedures are key factors means that most compressor failures are preventable. Therefore, it is of the utmost importance to understand the various ways in which these failures occur.

Following OEM guidelines for installation, startup and service are critical for installers of both ducted and ductless systems. For instance, the act of completing a compressor changeout can introduce contaminants to an HVAC system. Conversely, there is the rare occurrence of natural causes such as lightning or line voltage fluctuations that happen. On the other hand, proper routine maintenance improves the long-term reliability of the system.

This allows technicians to identify issues before they can cause a catastrophic failure. For instance, a dirty outdoor unit coil will result in the inability to reject heat, thus increasing compressor operating temperatures. When this happens, the compressor forces more expended energy while providing less capacity. Therefore, regular routine maintenance is key to keeping a system running well and avoiding compressor breakdown.

Other factors that affect compressor life

When it comes to compressor endurance, keeping refrigerant lines free of moisture or oxidization is very important. When refrigerant lines become contaminated it causes the internal lubricant to become acidic, which can eat away at internal windings.

Another factor contributing to compressor failure is incorrect refrigerant line sizing. When this occurs, it affects pressurization and evacuation to ensure the absence of leaks. It is also important to have correct minimum unit clearance and refrigerant charging procedures. These factors are critical to longevity and the life expectancy of the compressor.

Overheating is yet another variable that causes compressors to lose their operating capabilities. This usually happens when there is not enough refrigerant in the system. When overheating happens over an extended period it will cause the breakdown of winding insulation. Symptoms of overheating may include compressor short cycling due to increased trips on protection devices. This reduces heating and/or cooling performance, and an increases current draw.

Training and Startup Procedures

Contractors can help mitigate the chances of compressor failure by adhering to each manufacture’s startup procedure. This is because each manufacture has unique steps that must transpire in order to keep equipment running smoothly. Finally, attending a manufacturer training session is a good step in achieving longevity in HVAC systems.

April 9, 2019 by Matt Hanson

Business Owners Guide to Commercial HVAC

When business owners are in need of a new or replacement HVAC system, there may be many questions that arise. First and probably most importantly is the cost. However, cost not only pertains to the price of the equipment, but to the installation cost as well. Equipment cost will vary from one brand to another and between companies performing the install. Since most buyers are usually not HVAC experts, they often defer to the expertise of the engineer or contractor and may not search or understand that there are alternatives.

When it comes to Commercial HVAC systems many can be quite large. Furthermore, in many cases they were installed when the building was under construction. Typically, an HVAC system consists of condenser section placed on the rooftop or outside the perimeter on the ground. While outdoors these units are susceptible to weather damage and vandalism. Next, the installation of an evaporator section takes place, usually inside a mechanical room where it cannot be easily relocated.

How Replacements can be Made Easier

Generally, HVAC units need to be replacement after just a few decades. However, replacing an existing unit can be a very involved process. Installers routinely tell building owners that replacing the unit would be a daunting task. To complete the retrofit installation, it is often recommended to remove some of the walls or part of the roof. The reason is although the old unit can be chopped up and removed, it is very difficult to get a replacement unit in the space. Additionally, a crane is often needed to hoist the replacement unit into place, especially if the height of the building is several stories.

The total cost of an installation is broken down into separate categories; labor materials, and tasks. Installation companies will compute hourly wage times how many laborers it will take to complete the change out. Other expenditures could include permits, insurance, supervision, warehouse, crane rental, and delivery.

The selection of the proper HVAC system is yet another consideration. Owners, architects, engineers, and contractors have the choice of chilled water, refrigerant direct expansion, packaged, air-cooled, water-cooled, and VRF systems. Will the system be a central or floor-by-floor method? Each of these will have pro and cons and can be one of the more difficult decisions to be made. Sometimes decisions are based on building codes. Historic districts usually have restrictions on placing units outdoors or on the rooftop.

There is a better way!

For retrofit installations, the design of United CoolAir (UCA) products helps avoid all of the unnecessary costs that can occur. This is due to United CoolAir’s design that involves a complete indoor installation. This factor alone saves the unit from weather damage and potential vandalism. Additionally, UCA units are built as modular units that fit through doorways, meaning there is never a need for expensive rigging or demolition of the building. UCA units can also fit into historic buildings, thus avoiding the aggravation of code restrictions. Additional permits or non-allowance for outdoor equipment. United CoolAir HVAC units not only save in installation cost but their units last longer over the competition.

November 8, 2017 by Matt Hanson

A Flexible Alternative for Portable Environmental Control

The remediation industry has long relied on traditional equipment like mechanical dehumidification and desiccant systems. This is for the removal of excess moisture from flooded and fire-damaged buildings and environmental control. In many cases, these are the better choice for drying out the high moisture situations in preparation for later renovations. Still, a controversy persists whether or not air conditioning can is useful as effectively as a dehumidifier.

The answer is most definitely yes, but it depends on the unit type and application of environmental control. However, moisture removal is only one of the reasons why portable air conditioning should be a serious contender for remediation projects. Just as important as moisture removal is space conditioning during the renovation phase of the project.

How Mechanical Dehumidification Works

Portable air conditioning is not just for cooling outside tents and temporary facilities. When using the right type of portable air conditioner, it will not only dehumidify the facility but should also condition the space for the repair phase of the project.

In simple terms, dehumidification is the removal of water vapor from the air. This occurs by lowering the air temperature to its dew point, where it condenses for easy removal. Efficient dehumidification relies on two basic concepts. First, the air must be chilled as low as possible in order to effectively remove the moisture that is in the air.

This happens through the refrigeration cycle of both dehumidifiers and air conditioners. Air cooling happens as it passes over a cooling coil and a drain pan captures the moisture from the air as it condenses on the coil. Second, the ambient room or space temperature should as high as practical so that it can absorb the maximum amount of moisture from the space. This occurs by reheating the air as it returns to the room, and is done differently by air conditioners and dehumidifiers. This cycle continues until spaces have reached the desired temperature and humidity levels.

Dehumidification Versus Air Conditioning Systems

A key difference between dehumidifiers and air conditioners is how the heat from the refrigeration cycle is processed. Dehumidifiers use the heat generated by the refrigeration cycle to immediately heat the air re-entering the space. This results in dry, warm air leaving the unit.

Air conditioners, on the other hand, reject the waste heat away from the space, usually to an external air-or water-cooled condenser. The conditioned air returns to the space dry but cooler. Since maintaining a warmer ambient is important for dehumidification, good quality portable air conditioners are available with supplemental electric heating coils. This is also true in heat pump models to reheat the cooler, dry air.

The temperature is controllable with accurately for efficient dehumidification, and the availability of heating and/or cooling is useful during the reconstruction or renovation phase. Another key difference between dehumidification units and air conditioners is the way they control sensible and latent heat. Sensible heat is essentially the air temperature within the space and latent heat is the additional heat in the form of moisture in the air, the relative humidity (RH).

An air conditioner measures and controls temperature, cooling the space until the thermostat reaches its set point. A dehumidifier removes moisture until the humidistat reaches the desired RH level.
The sensible-to-latent heat removal ratio for a dehumidifier is 50-50 while an air conditioner is closer to 70-30. In other words, dehumidifiers ring out more moisture, but they generally have poor to no control of space temperature. Air conditioners have great control of space temperature but remove moisture at a lesser rate.

Which System Is Better?

If your only interest is maximum moisture removal in the shortest time, straight dehumidification is probably the better choice. But when moisture removal is lower and spaces will require renovation or some type of post-construction, a portable air conditioner should be your number one selection.

Portable commercial air conditioners can easily reach 2,000 CFM for a five-ton unit when in the cooling stage. However, to improve the moisture removal characteristics, lowering the fan speed by up to 50% improves its dehumidification performance. By slowing the warm, moist room air traveling over the cold evaporator coil, additional moisture can be removed.

Portable air conditioners are available in a variety of configurations and sizes as high as 30 tons for even the largest of buildings. Smaller units can have wheeled bases making them easy to transport and position. Additionally, their narrow cabinet design will pass through a standard 3/0 door opening without modification.

The Additional Benefits Of Portable Air Conditioning

The key to any job site is to maintain Indoor Environmental Quality (IEQ) during reconstruction and renovation. Portable air-conditioning systems offer the restoration and remediation industry an excellent tool to assist in the safe and efficient completion of restoration projects.

It’s commonplace during renovations to seal the affected area by turning off the air conditioning and isolating the airflow from the rest of the building. The goal is to maintain a negative pressure in the workspace (or positively pressurize other areas). This is to prevent the migration of air contaminants from work areas to occupied areas.

Portable air conditioning units will retain a controlled environment by maintaining specific relative humidity and temperature conditions, and they can also effectively filter the circulated air. That means the same unit that removed the initial moisture also provides an ideal workspace environment. Worker productivity maximization and space conditions improve through dust control.

The Importance of Conditioned Spaces

Conditioned space is critical for building materials and finishes applications. The installation of hardwood floors and wood paneling requires the normalization of materials at the right temperature and humidity to prevent warping or later expansion/contraction.
Controlled humidity will protect metal surfaces from oxidizing and help wall coatings dry faster and more completely. Renting a single unit for moisture removal and space conditioning is generally less expensive and requires less set up time.

Equally important is the prevention of mold and fungus. Molds like Aspergillums can grow on modern building materials such as gypsum board and ceiling tile if allowed to remain wet for more than 72 hours. Spores become airborne during repair and/or disturbance of the building and have low settling velocities, remaining in the air for long periods of time. A portable air conditioner continues to dehumidify the space and filter the return air as long as space conditioning occurs.

Selecting the Portable Air Conditioner That’s Right for Your Application

Portable air conditioning units are available in a variety of sizes and configurations. The purpose-built dehumidifier units are available through rental distributors are generally small in capacity. As an example, quality manufacturers like United CoolAir Corporation offer one of the largest selections of portable systems. These units have multiple capacities capable of conditioning even the largest of commercial spaces.

Portable horizontal air conditioning systems are the most popular and have the widest range of sizes and arrangements. These smaller horizontal units provide needed flexibility and are useful for indoor or outdoor installations. Typical cooling capacities can reach as high as 15 tons and include the option for electric heating.

Narrow Design Aides in Mobility

Since mobility is paramount for these units, they are narrow in design to navigate doorways and entrances. This includes integral unit-mounted forklift pods or casters for easy mobility. For the really large projects or where it makes sense to replace multiple smaller systems with a single unit, consider a larger, high capacity system. With sizes ranging up to 30 tons of cooling, these units include up to 80 kW of electric heating.

Narrow in design, they are easily positioned using the built-in lifting pods are stacking is possible if necessary. Trailer-mounted units are also an option for outside installation. Also available are vertical portable air conditioning and heating units. While not as popular as horizontal models, they offer both bi-directional free blow and ducted operation. Most find this a great application in large open spaces.

Typical sizes can range from three to 30 tons with up to 60 kW of heating. These narrow footprint units are easy to transport and move into position using the forklift pod. Installation can be inside or out as conditions allow.
With the right manufacturer, you can select from standalone in-line blowers and heaters. These units work in conjunction with larger tonnage portable air conditioners for more reheat capability and longer flexible duct runs.

The Future of Environmental Control

Today’s portable air conditioners are easy to install with features like Camlock power connections, duct collars, built-in circuit breakers, and more. Many include multiple ducting options with high static pressure for long duct runs. Quality units are also equipped with an internal thermostat and offer an option for remote control if required.

Always choose a reputable portable air conditioning brand with a proven track record of performance. They are your number one source for getting a unit that best fits your application. However, not all portable air conditioning units construct to the same standards. It is not uncommon to find traditional building air conditioners, or even rooftop designs, modified for portable use.

Summary

These units exist for stationary installation and cannot withstand the continuous movement and transportation requirements necessary for portable equipment. When used in portable applications, they are prone to refrigerant leaks, component failures, and reduced life expectancy.

Finally, it’s also important to evaluate the suppliers of portable air conditioning rental equipment available in your area. While most will be helpful in getting you started, choose one that will help you select the right size, type of equipment, and accessories for your application. Technical support exists in the event of a malfunction, and if they carry an inventory of equipment should it be needed quickly.