Air Conditioning System Installation Process From Start to Finish

Air Conditioning System Installation Process Start to Finish
Installation
Air Conditioner

Air Conditioning System Installation Process From Start to Finish

04-27-2020
Joshua Rodriguez

I am the Install manager at Fire & Ice, since 2017. I have spent 28 years in this business and have experienced nearly every aspect of HVAC from Industrial, commercial, and residential buildings. From design, install, service, or sales, if it moves air, I’ve touched it.

One of the most common questions asked by customers who are replacing their central air conditioner is, “what all is involved when I get my central air conditioner replaced”? Most homeowners don’t realize how precise this process is.

In this article, we are going to cover the entire installation process, from start to finish! 

Before, during, and after the completed installation of a new central air conditioning system, several processes must be performed. These processes must be completed with precision in line with the highest standards according to local codes, manufacturers specifications, and industry standards.

If you fail to follow these processes, you will be left with an unpredictable, energy-wasting, and comfort robbing trash can in your backyard. However, if installed by a good HVAC company that adheres to these processes, your new central air conditioner will provide years of comfort, efficiency, and reliability. Your air conditioner can last 20-25 years with proper maintenance.

Planning the Replacement or New Installation of Your Central Air Conditioner

Most air conditioners replaced today are between the ages of 8 to 30 years old. Imagine how much has changed in the world around you in the past 8 years let alone the past 30.

Modern air conditioners are 20% to 50% larger in height, length, and width. Allowing for a larger coil, in turn, making the air conditioner more efficient. Because of the larger size of modern air conditioners, the current location of your existing air conditioner may not accommodate the new one. Sometimes the air conditioner must be relocated. In most cases, this creates additional costs. 

Consideration for clearances required for air and service accessibility is needed in case of relocation. Clearances from obstructions on all sides and service panels, along with distances from utility meters. These are common amongst most manufacturers.

Modern air conditioners are also significantly quieter than their predecessors. This is great news If your existing air conditioner is by a window, on a patio or deck, and you don’t have the option of relocating.

Collecting Information During the Home Estimate Prior to Installation

During the in-home visit, the estimator has the responsibility of reviewing the existing air conditioning system. Important information needs to be collected so they can provide you an accurate proposal. This information would then get passed on to the install team.

The install team can then make sure that they are prepared with the proper equipment and required supplies before heading to the job for the day. Having the proper information before the day of install increases the chances of the job being completed successfully and in a timely manner.

The Arrival of Install Team, Review, and Safety

On the day of install, before the install team arrives you will receive a phone call or text message letting you know they are on their way. Good HVAC Companies will send pictures accompanied by bios of the install team that will be working at your home ahead of time.

This is an additional safety and comfort factor before a stranger enters your home. 

Before the install begins, the lead Installer will share and review with you a packet containing the job information. This packet contains the equipment information, accessories to be installed, and any special instructions by you given to the estimator prior to the sale.

It’s important to allow a few moments for this review. This will prevent costly and aggravating mistakes from happening during the install. Communication is a key component to a successful installation. 

While you are reviewing the job details with the lead installer, the second on the team in most cases uses this time to start laying down floor protection and getting tools and equipment in place. They will also start a safety process that includes turning off electrical circuits and gas supply to the existing HVAC equipment.

Removing the Existing Central Air Conditioner

Your existing air conditioner contains a refrigerant that needs to be removed before a new central air conditioner can be replaced. According to the EPA standards, it is unlawful to openly vent this refrigerant in the atmosphere.

You can learn more about the EPA's prohibition on venting refrigerants on their website.

A recovery machine must be used along with a recovery tank to safely and legally remove the refrigerant in the existing central air conditioner system. This is the only process that allows for the safe removal and proper handling of the refrigerant.

Any individual handling any refrigerant, or equipment containing refrigerant must have an individual EPA certification. An EPA certification only certifies the name listed on the certification. Therefore, each member of the install team, service team, or anyone who would handle refrigerant or equipment containing refrigerant are required by law to have their own individual EPA certification.

Once the refrigerant is recovered properly, the high-voltage electric wiring, low-voltage electric wiring, is then disconnected from the existing air conditioner. The high voltage wiring comes from the electrical panel to an equipment service disconnect box located near the air conditioner. From the disconnect box, a “whip” (flexible electric conduit) carries the power to the air conditioner. 

The service disconnect is there to interrupt power between the electrical breaker supplying power and the air conditioner. A service disconnect is code for servicing and safety in case of emergencies to shut down the air conditioner unit. Good HVAC companies replace the disconnect and the whip when replacing an air conditioner.

If there is not currently a service disconnect installed with your air conditioner, one is required by code to be installed with the new air conditioner. There are specific installation guidelines for sizing and wiring the disconnect properly.

The circuit breaker should be turned off in the electrical panel before any work is to be done inside the service disconnect. Once all the existing connections are safely removed, the existing air conditioner is ready to be removed and loaded in the truck. 

Preparing the Area for the New Central Air Conditioner

In most cases, the existing location of the air conditioner will require some prep work to be done before the new air conditioner can be set in place. This prep work includes the removal of the existing pad and leveling the ground for a new pad the new air conditioner will set on.

New air conditioners are larger and taller than their predecessors. There are also times where the ground has sunk. So, before the new pad can be set the ground must be leveled. Good HVAC companies use a gravel base to level out or build up the area where the new air conditioner will be placed.

Air Conditioner Sitting On Unleveled Concrete BlockAir Conditioner Sitting On Leveled Composite Pad

Some people think that it is better to have a concrete pad poured for the new air conditioner to set on. A concrete pad is not necessary and can crack and shift drastically. When this happens, it is very difficult to repair or remedy. Instead, a composite pad is preferred by Good HVAC installers. The composite pad is purposely designed to be outside and last the lifetime of the new air conditioner.

Once the new air conditioner is installed it cannot be moved or lifted safely without damage in most cases. The copper refrigerant lines are not flexible. They are rigid and the refrigerant inside is pressurized. Moving it after it is connected could permanently damage the system. A thick composite pad with a flat surface is suitable for the air conditioner to set on. A composite pad can avoid damage to the air conditioner if it needs to be leveled in the future. 

Removing the Existing Indoor Evaporator Coil

The indoor evaporator coil is the other half of your air-conditioning system that sits above the furnace. If you have a “down-flow” application, it will sit below the furnace. This is what the other end of the refrigerant lines are connected to.

The indoor evaporator coil has two variations. One is cased and the other is uncased. In either application, the sheet metal plenum must be disconnected before the new coil can be installed. This process can be complicated when access to the coil is restricted.

Furnace, Cased Evaporator Coil, and Plenum

The most common restrictions are rooms built around the system such as closets or finished basements. This prevents access to all sides of the coil or plenum. An additional charge may be added to the cost of the job based on difficulty. Because most indoor coils are more efficient, they are taller. Additional prep work to the supply plenum may be required before the new coil can be installed.

Removing the Existing Copper Refrigerant Lines (Line Set)

Now that both components (air conditioner condenser and the indoor evaporator coil) have been safely disconnected, the existing refrigerant line set can be removed. This is a set of two copper lines, one supply, and one return, that the refrigerant travels from the outdoor condenser then back into the indoor evaporator coil.

The refrigerant line set is usually strapped to the bottom of the floor joists. These straps are removed, and the line set is taken down. The line set must be replaced in every case that it is exposed and accessible. The replacement of the line set is the most recommended practice.

Refrigerant travels through the lines along with oil. In older air conditioning systems, the oil in the existing line set is different from the oil found in the new air conditioner. These oils cannot be mixed without damaging the new air conditioning system.

Sometimes the line set is concealed by a ceiling or in a wall, or maybe it is buried underground or in concrete. Sometimes providing access is not an option or possible. In these cases, you have the option of finding a new location to run a new line set or reuse the existing line set remains. If the existing line set must be reused, before it is connected to the new equipment it must be flushed and cleaned properly, then pressure tested. It is never recommended to keep an existing line set if it, in fact, can be replaced.

Installation of the New Indoor Evaporator Coil

There are two options when installing a new evaporator coil for any new air conditioner system. The preferred option is a cased coil because it comes in an insulated cabinet with removable panels on the front that allow access to the coil inside.

The cased coil is also designed to sit on top of the furnace without any modifications. It comes with rails that the coil sits on inside for ease of replacement or servicing when required. In most cases, it will be painted and matches the color of the furnace. The biggest benefit of using a cased coil is to the consumer as the coil itself is already installed in an insulated manufactured case, making the failure rate from an improper install highly unlikely regardless of the skill level of the installer.

Cased Evaporator Coil Cut-Out

When using a cased coil, it is already “installed” by the manufacture and merely needs to be placed on the top of the furnace. The final step at that point is to connect and seal it to the exiting sheet metal plenum. There is less labor, and it provides a cleaner overall look when completed. A cased coil is available in all variations of the install application. These variations are up-flow, downflow, and horizontal (right or left) airflow requirements of the furnace.

A second option is an uncased coil. The uncased coil is merely just the coil without the insulated cabinet. They have more installation requirements and longer preparation time. They are available in the same variations as the cased coil.

Uncased coils are typically more difficult to install, you lose the insulation factor around the coil, and unless a custom door is built, there is not any accessibility to the coil for service. However, an uncased coil will provide the same comfort and be just as efficient as a cased coil when installed properly.

Before the coil can be built into the existing sheet metal supply plenum, there is specific preparation required. All manufactures requirements are found in the installation manual for the specific coil being installed. These guidelines are to protect not only the coil but the furnace it is being installed on top of as well. Failure to follow the installation manual’s guidelines may result in damage to the furnace as well as the coil.

The drain pan on the coil is plastic, so rails need to be fabricated by the installer to make sure the coil is sitting the proper distance above the furnace heat exchanger keeping the drain pan from melting. If the drain pan melts into the furnace it could permanently damage the furnace, or in the most severe case cause a fire.

Once the rails are built and installed, the coil can be installed into the supply plenum. If the plenum is larger than the coil, a sheet metal pan must be built with an opening provided below the coil. This opening needs to mirror the bottom opening of the coil for proper airflow from the furnace going through the coil.

If the opening is not big enough, or too much air goes around the coil instead of through it, the coil will freeze into a block of ice. This can damage the coil and cause a refrigerant leak by cracking the tubing carrying the refrigerant. When the ice melts, it falls into the furnace as well as the floor. This could cause damage to several electrical components inside the furnace.

Once the coil rails, and pan if required, and the coil is installed in the plenum the final step would be building the front of the plenum. It is possible to build an access panel type of door into the plenum to cover the coil. It is not required by any code or manufacture specification, so it would be up to the installer on how they would build the cover. In all scenarios, the cover must have holes provided for the refrigerant lines, and then also for the condensation lines to be connected.

The type of coil chosen is mostly based on the install application. Some applications won’t allow for a cased coil. For example, a cased coil may be too tall, and an uncased coil will be the only option that would fit. In any case, if the coil is installed per code and manufacture specifications to the existing duct system, can drain properly, and is sealed from air leaks, you will enjoy the same level of comfort. There is no difference in warranty or life expectancy between either type of coil.

Installation of the New Copper Refrigerant Lines (Line Set)

The new refrigerant line set is a combination of two individual copper lines. One line is always bigger than the other and is insulated. The bigger line is called the suction line, and the little one is called the liquid line. They come packaged together rolled in a coil. It is available in multiple selections of lengths from 15ft up to 50ft. It is very rare that you would need more than 50ft of line set in residential applications.

You want to install this line set with minimum turns or bends and as a solid piece when possible. For this reason, it is made of a soft copper so it can be formed as needed, sometimes by hand, and in tighter spots with a tubing bender. 

Installing the line set as close to beams or trunk ducting is common. Securing it at least every 4-6ft is recommended. When choosing strapping or hangers to secure line set, choose plastic or copper if possible. If a metal strap or clamp is used, make sure to protect the copper it may touch by wrapping the point of contact with tape or armaflex insulation to prevent galvanic corrosion.

Galvanic corrosion (also called bimetallic corrosion) is the breakdown of the metal when two dissimilar metals come into contact. This does take some time to occur based on a variety of conditions. Nevertheless, if allowed to occur it could eventually reduce the integrity of the copper refrigerant line over time until it causes a leak.

After at least most of the hangers are installed, the line set can now be put in place. Typically, you would start with the suction line (the bigger line that is insulated) and roll out one end about 3 to 4 feet, leaving the rest of the roll in a coil. The unrolled section would get pushed through a hole drilled through the band board of the house to the outside near the placement of the air conditioner. Enough of the line should be pushed out to reach the service valve of the air conditioner. It’s always better to have a little extra.

For now, it can be left sticking straight out of the house until both lines are run. They will be formed later when hooking up to the air conditioner. The hole size should be somewhere between 2-2.5” in diameter based on the actual line set diameter being used.

After you push what you need outside by the air conditioner, then the line is secured by a couple of hangers nearby the hole and then another hanger back a couple of feet. The line is then carefully uncoiled and formed along the floor joists up against the trunk line ductwork or a beam, as straight as possible until long radius turns or bends are needed. Along the way, it gets put into the hangers that have been installed previously securing it in place.

The line-set will run from the air conditioner outside to the new indoor evaporator coil on top of the furnace. After the suction line has been installed and secured, the smaller uninsulated liquid line is run along the suction line, secured in the same hangers. A line set should be new, installed as one piece, free from any sharp bends or kinks, and secured with an appropriate hanging system.

At some point, there will also be a small low voltage control wire that runs from the furnace along the line set to the air conditioner outside. The small existing wire coming from the thermostat to the furnace sends a low voltage signal to the air conditioner to turn on and off when a call for cooling is needed or has been satisfied.

Setting the New Air Conditioner Condenser

Now we have a pad set, leveled, and in the proper location. Our refrigeration lines, and our electrical disconnect ready to hook up to our new air conditioner condenser.

Removing the new air conditioner from its crate and just setting it on the pad is the first step in getting the new air conditioner connected. After the air conditioner is uncrated it should be inspected for any damage. Sometimes from shipping or handling, the louvered panels could be damaged or even the coil itself. If visible damage is found, the installer should immediately notify you.

If a dent has occurred, it does not mean there is any real damage to the unit and how it will perform. Your install technician can assist you with any questions or concerns. You do have the right as a consumer to not accept the damaged unit and ask for another one. If everything is fine, the unit will get set on the pad and the hookup phase begins.

The new line set that was installed is formed and fitted to the appropriate service valve located on the new air conditioner. The service valves provide a connection point for the line set to connect to, while also isolating the refrigerant contained inside the unit until it is time to release it. Service valves also allow for the outdoor condenser portion of the air conditioner to be isolated from the indoor coil and line set for future service or repair needs when needed. Isolating the refrigerant keeps you from having to replace it with all new refrigerant in case of a repair in the future.

After the line set is fitted to the service valves, they must be brazed in. Brazing is a process using two gasses (oxygen and acetylene) and a filler rod made of an alloy metal and silver to join the copper line set and service valves. Like welding two metals, the valves are heated to a minimum of 1200 degrees Fahrenheit or until the filler rod will flow to welding the connection. If this process is completed properly, the copper line set, the filler rod, and the service valve are all melted together for a tight leak-free connection.

Filter Dryer Installation

When installing a new air conditioner condenser, you must always install a liquid line filter drier into the refrigeration system. Most new air conditioner condensers come with a liquid line filter drier for you to install. These are required to be installed into the new line set.

Manufactures recommend the filter drier be installed close to the TXV valve at the indoor coil, as often as possible. This keeps the expansion valve (TXV) protected and keeps the filter drier from being exposed to weather where it could rust. There is also an arrow for flow direction. This arrow must always be in the direction that is going into the indoor coil.

Filter driers are a key component in the refrigerant system. Filter driers serve two main functions. The most important function of a filter drier is to absorb moisture. Secondly to provide physical filtration.

Any contaminants in the refrigeration system are harmful. Water or moisture is the worst. Moisture is entered into the system in different ways.  If a system is not evacuated properly, moisture will exist in air molecules not evacuated. Moisture also can come from leaks or motor windings. The water can cause corrosion and create failure in metallic parts. Water or moisture can also react with the POE oil in the refrigerant system. This is called hydrolysis which forms acids in the system. Acids, moisture, or any other contamination in the lines will be extremely dangerous to the integrity of your new air conditioning system.

All good HVAC companies have strict processes in place for their install teams to prevent failure as much as possible. Any time a refrigerant line is open to the atmosphere it is vital to install a new filter drier. Whether it’s a new system being installed with a new line set, or a service refrigerant repair to your existing system, a filter drier must be installed in the liquid line. 

This brazing process is the same for connection to the indoor evaporator coil. Sound easy? Maybe. If you have been trained properly, then it is easy. Only trained professionals should ever attempt to braze air conditioner units, coils, or components.

The gasses used are explosive. There is an open flame outside and inside the home. It can be dangerous to the installer, the homeowner, and the home, causing permanent damage without proper training. Before the brazing process takes place, manufacture instructions and industry standards call for certain processes to happen before during and after the brazing process, and before the new refrigerant can be released into the new lines.

The following process for brazing and preparing the line set for refrigerant is the most important step when installing an air conditioner. None of this process should be skipped or modified. Sadly, this process is unknown or not followed to most install teams. This process requires specific tools and equipment to complete.

Not all companies are equal in training or processes. Not all install teams are equipped with the proper equipment. Sadly, this process is failed on a regular basis. A good HVAC company will have all the tools and processes needed to install the air conditioner professionally.

After the line set is fitted properly into the service valves and indoor coil, heat protection needs to be applied. Heat protection can be a heat-absorbing paste, wet towels, or rags. Anything that would keep the heat spreading into either of the coils is acceptable. The service valves on the outdoor condenser contain rubber O-rings that will melt if not protected. If the valves are overheated and the O-rings are damaged, the refrigerant will leak past the valve into the line set, losing the factory charge.

From the factory, the air conditioner condenser is prepared, cleaned, and the refrigerant is added. If the refrigerant is exposed before the process is completed, it becomes contaminated, along with the condenser coil. All the refrigerant would need to be recovered and the condenser coil would need cleaned and prepared again before any refrigerant could be added.

Most indoor coils have a metering device called an expansion valve that will be damaged if not protected from the heat during brazing. If these get too hot, or any contaminants are introduced the expansion valve will be compromised and fail to operate.

Once the heat protection is completed a tank containing a gas called dry nitrogen is hooked up to a regulator and possibly a manifold gauge set. This is to allow for nitrogen to be purged while brazing. The nitrogen protects the inside of the copper tubing from oxidizing during brazing. The oxidation produces a scale, if that scale gets into the system it will cause severe damage. The damage will not always be present immediately. The HVAC industry requires brazing with nitrogen every time to prevent the opportunity for the scaling to be present.

Brazing with nitrogen, when done properly, will give the system maximum opportunity for performance, reliability, and dependability. After the system is brazed in both the indoor and the outdoor components, it must be checked for leaks using the same dry nitrogen, to a maximum of 150psi of pressure. Using the dry nitrogen to pressure test the system achieves 3 main goals. It’s a preliminary leak test, the dry nitrogen will pick up moisture and purge some contaminants out of the system upon its release. It is very important to verify with the installation manual provided by the manufacture what they recommend for pressure. Most systems are designed for 150psi when testing.

If there is too much pressure added, it would be too high for the service valve O ring to hold back. If any dry nitrogen gets past the O ring seal on the service valve it will bleed into the refrigerant contaminating it. All the refrigerant contained in the condenser from the factory will be compromised and will have to be recovered, then the coil cleaned and prepped for more refrigerant.

If the preliminary leak test with nitrogen holds for a minimum of 10 minutes, then it’s time to move on to the next crucial step. This next step is vacuuming the system to a minimum of 500 microns typically. The manufactures recommended vacuum is found in the installation manual. Refrigeration systems are designed to operate with only oil and refrigerant flowing through them.

Our atmosphere is made up of oxygen, nitrogen, and moisture. These are enemies to the system's operation and may enter the system during install or servicing. Removal of these, along with air or other non-condensable products is required. This is achieved through the vacuum process when installing the air conditioner. The vacuum process can take no less than 30 minutes and up to an hour or more depending size of equipment coils and length of line set.

This is a crucial junction during the install process. Failure to provide a dry, moisture-free atmosphere before introducing the refrigerant into the rest of the system will in all cases promote inconsistent operation, and eventually permanent failure of the system.

To achieve a successful vacuum on an air conditioning system there are several key tools and equipment that must be used.

  • Reliable vacuum pump
  • Micron gauge
  • Manifold and hoses
  • Vacuum rated core removal tool

The vacuum must achieve 500 microns or less in the system and hold the vacuum for this to be successful. This is also the second and final leak test. If a system does not hold a vacuum, then there is a leak somewhere.

Once a proper vacuum is achieved and has proven to hold, the air conditioner from the service valve, the entire line set, and the indoor coil are all ready to have refrigerant introduced to them. Refrigerant is the only product that can “break” the vacuum. If hoses are disconnected from the system before the refrigerant has been released into the system, the atmosphere will break the vacuum. If this happens the vacuum process must be redone before refrigerant can be introduced.

With the hoses still connected to the service valves of the air conditioner, the refrigerant is released into the system essentially breaking the vacuum by opening the suction side service valve first followed by the liquid side second. 

Installation of the New High and Low Voltage Wiring

For the air conditioning system to operate the high and low voltage wiring must be reconnected. Using the existing power supply from the electrical panel inside the home that is run out near the air conditioner, a new service disconnect box will be mounted. The disconnect is mounted securely to the side of the house using appropriate fasteners, based on the type of surface it is being mounted to.

There are two main types of disconnect boxes that are used. One is a fused type and the other is non-fused. They are both outdoor rated. A fused disconnect allows the proper over protection required by the manufacture. This type is most common and required when the main circuit from the panel exceeds the maximum required overcurrent protection. It also allows for additional safety to the air conditioner condenser.

A non-fused disconnect may be used only in cases where the breaker matches identically to the manufactures listed maximum overcurrent protection. There is a minimum and a maximum required overcurrent protection. You must be within these guidelines. It will not pass code requirements if they are not. For example, if you have an existing 40-amp circuit that supplies the disconnect, but the listed overcurrent protection is only 30 amps, you must use the fused disconnect and install 30-amp fuses with it to properly protect the air conditioning condenser. If the amperage from the breaker matches the maximum or the minimum over current protection, a non-fused disconnect is acceptable.

The service disconnect has specific locations for the high voltage circuit from the panel to be connected and specific locations for the power to get to the air conditioner itself through the electrical whip. They are clearly identified as “Line” (wiring from the electrical panel) and “Load” (the whip that takes power to the air conditioner). This allows the pull inside the service disconnect to break or disconnect the power supply to the air conditioner without having to shut the breaker off from the main panel.

Because the air conditioner is outside, it would be cumbersome to run in and out of the house to turn the power on or off in case of emergency or servicing. The service disconnect is required by state and local code requirements.

There are also requirements for placement of the air conditioning condenser. It boils down to making sure there is proper accessibility. All the electrical connections should be made according to the NEC (National Electrical Code). The low voltage control wire is connected directly into the air conditioning condenser at the proper locations according to the air conditioning condenser install instructions.

This is the “signal” from the control board in the furnace sent through the wire to the air conditioner when the thermostat calls for cooling. The low voltage control wire is what allows the air conditioner to cycle according to the parameters set regarding temperature and humidity inside the home. The low voltage wiring is connected to the control board inside the furnace on designated terminals.

Installation of the Condensate Drain Line

The moisture removed from the home during the cooling process travels down a plastic P.V.C pipe. It must be connected to the primary side of the evaporator coil. The evaporator coil has a primary and a secondary drain location. The primary condensate drain line will travel from the indoor evaporator coil to an appropriate floor drain or condensation pump.

A condensation pump is used where a proper floor drain does not exist in the home. There are also other reasons where a condensate pump is required or may be most beneficial to install. The important thing to remember if a condensate pump is used is that it will require a minimum of biannual cleaning to maintain performance.

Any condensate tubing or piping should always be secured and glued with the proper cement. A trap and an overflow safety switch must also be installed in the condensate system. This is to protect the equipment and the area from flooding due to a restriction. The safety overflow switch is connected to the secondary port on the indoor evaporator coil and wired into the furnace control to shut down the system when it is tripped.

Startup Commissioning Process

The startup and commissioning process is done after the system is completely installed and ready to operate. The system is turned on and must run for 15-20 minutes. This will allow the refrigerant to flow through the system and start the air conditioning process.

Upon initial startup of the new air conditioning system, the house should be very warm or have a “load” with a warm enough temperature inside the home to allow for the minimum potential to charge the system accurately. A temperature above 75 degrees Fahrenheit is recommended in most cases. This allows the components in the air conditioning system to be in full operation to allow maximum cooling potential during charging.

Sometimes running the furnace to heat the house up is a common practice to provide the necessary load on the home. After the 15-20 minutes of operation, the system can now be commissioned. A check out of thermostat operation, system sequence of operation, and multiple measurements are done with the information recorded. While the system is operating, the following data is important to collect to ensure proper operation within manufacturers' specifications. The following data should be collected and adjusted if necessary, to be within manufacturer specifications of optimum cooling.

  • Suction and liquid line pressure
  • Suction and liquid line temperature
  • Superheat
  • Subcooling
  • Outdoor ambient dry bulb temperature
  • Indoor ambient dry bulb temperature
  • Indoor wet bulb temperature
  • Return air temperature
  • Supply air temperature
  • Static pressure from return side, supply-side and then total static readings
  • Temperature drop calculated
  • High voltage current reading
  • Amperage on the blower motor, outdoor fan motor, and compressor
  • Low voltage current reading
  • Line set length
  • Amount of refrigerant if any, added to system
  • Distance above or below the outdoor unit is in relation to the indoor coil
  • Blower speed tap/CFM recorded

This is the basic list of the proper data that should be known, adjusted if necessary and then the final reading recorded. This is the only way to know for sure how the system is operating and if it is within manufacturing specifications. If any of these do not fall within manufacture specifications your system may not be warranted by the manufacture.

There are multiple benefits to doing a commissioning report. The benefits to you are that you receive a properly set up and adjusted system for maximum comfort, efficiency, and dependability. It also ensures the manufactures warranty will be in full effect. The benefit to the company installing the system is that it gives a baseline of operation in case of any issues that may arise later.

It also gives the installing team confidence that before they leave, your system is in perfect operation. It is very common for systems to be installed and started up without much consideration for proper commissioning.

Unfortunately, most companies turn it on and walk away the moment cold air is coming through the vents. Proper commissioning is a specific process that requires training and special equipment to perform the process correctly. It also requires additional time on a job-site or labor. Commissioning is the only way to know for sure exactly how well your system is operating. Skipping this process would cost a company less, which in turn could offer a lower estimate price. That is not doing what is right for you and your home. A good HVAC contractor will have trained install teams that will properly commission your air conditioner before they leave the job.

Clean up and Closing Process

The cleanup process is simple. All material and old equipment should be loaded up and taken away from the home. The floor protection should be rolled up last, keeping all debris from the install inside the drop cloth.

All areas should be swept and free of any materials or debris. The area would be expected to be left in the same or better condition than it was found. A walkthrough of what was done during the install should be completed with you. Going over all the safety, maintenance, warranty, and all special instructions are expected.

A visual inspection of the work completed should be offered. Finally, a review of the commissioning, and thermostat operation. After the final walkthrough, final signatures and payments are collected. 

Installation Completed Professionally

The job is now complete!

Are you looking for a good HVAC company to install your new Air Conditioner system? There are many procedures in the installation process that need to be followed. This includes Manufacture install guidelines and national, state, and local codes. Multiple details need to be addressed before, during, and after the installation to assure a high level of comfort, efficiency, and a long-lasting product.

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