Air Conditioning Installation: A Step-by-Step Process

Whether it’s been 15 or 20 years since installing your air conditioner, the time may have come to replace it. That’s a pretty good length of time. Even well-maintained AC’s eventually reach the end of their life. At NEXGEN, we’ve provided air conditioning installation in countless homes and businesses. In this step-by-step guide, we’ll provide a look into our process that ensures your investment pays off.

Step 1: In-Home Consultation

Assuming your current AC isn’t fixable, we’ll send a licensed contractor to evaluate what you have and what type of air conditioner is best for your home. Newer air conditioners tend to be larger to accommodate larger, more efficient coils. Therefore, the location of your existing AC may not be sufficient. A different area may need to be considered.

Another factor is the unit’s cooling capacity. You don’t want an AC that’s too small or too big or it won’t run efficiently. This can reduce comfort and strain the system so it costs more to run and repair more frequently.

Step 2: Removing the Old System

To remove an old AC system, several complex tasks are required. First, the refrigerant must be removed; this involves specialized equipment and a trained technician. By law, only EPA-certified personnel can remove, handle, and dispose of refrigerant, which can be toxic. Coolant cannot be vented into the open air; a sophisticated machine pumps it into a recovery tank.

It's also necessary to protect areas of your home. Air conditioning equipment is heavy and there may be debris to clean up. During this process, installers will cover floors and furniture for protection and also inspect for sealing issues in your home and air duct leaks. These can impact the performance of a new system so must be fixed before installation begins.

Step 3: Preparation

The pad for the old outdoor unit must be replaced to accommodate the new air conditioner. Newer units are larger and wider. The ground may also need to be leveled before the technician can set the new pad. A gravel base should be used to level the area or build it up, while a vibration-absorbing composite pad is preferred over poured concrete that can crack and shift.

The area must be stable, as moving or lifting the air conditioner can cause severe damage. Rigid internal components cannot withstand much motion, while some are pressurized as well. Once the system is connected, it must remain in place, so the pad won’t need repair during the unit’s lifetime.

Before the indoor evaporator coil is replaced, the metal plenum is disconnected. Refrigerant lines, which consist of two copper pipes, may be reused (and first flushed, cleaned, and pressure-tested). However, a technician will likely recommend installing a new line.

Refrigerant lines are often strapped to the bottom of floor joists. Straps must be removed before taking out the line set. Line sets may also be located within ceilings or walls or buried underground. To make things easier, a new line set may be run while the old one remains.

Step 4: Outdoor Unit Installation

The AC condenser is placed on the composite pad and inspected for potential damage. Next, the line set is fitted to the new unit’s service valve, which isolates the refrigerant and the outdoor condenser from the indoor coil. This avoids having to replace refrigerant if a repair is needed. The copper line set and valves are brazed, or welded, together to ensure a leak-proof connection. Then the filter dryer is installed in the condenser, preferably next to the expansion valve, to absorb moisture and provide filtration.

Step 5: Wiring Installation

The new service disconnect box is mounted to the side of your house and wired to the electric panel. An installer may provide a fused box that supports overcurrent protection, or a non-fused box if the existing breaker matches the AC manufacturer’s listed maximum overcurrent protection. High- and low-voltage wiring will then be reconnected; line, or wiring from the panel, and load, a power conduit to the AC, is connected. All electrical installations are installed following the National Electrical Code (NEC).

Step 6: Indoor Evaporator Coil Installation

A cased evaporator coil is preferably installed. It has an insulated cabinet with panels that allow access to the coil and sits on top of the furnace. The coil is then connected and sealed to the existing sheet metal plenum. Uncased coils require additional preparation and installation work before connecting them. Rails must be installed to ensure the coil sits above the furnace heat exchanger at the proper distance, or else the drain pan can melt. But if the opening isn’t big enough or too much air can flow through, the coil will freeze.

Step 7: Refrigerant Line Installation

Refrigerant line sets include two copper lines; the suction line is larger and insulated, while the liquid line is smaller. Rolled into a coil, these are available in lengths of 15 to 50 feet. Lines are set near beams and ductwork, if possible, and secured every 4 to 6 feet with plastic or copper strapping. Once hangers are installed to secure the lines, the suction line is usually installed first and connected to the AC, and run to the indoor evaporator coil. The liquid line is then run along the same path and secured.

Installers will take care not to bend, kink, or otherwise damage the lines. During the process, the installer will push unrolled sections of tubing through a 2” to 2.5” hole in the outside wall near the AC. Just enough line is then pushed out to reach the service valve. When refrigerant is added, special care is taken not to expose it to the air and contaminate it.

Heat protection is then applied and dry nitrogen is used to protect the interior of copper tubing from oxidation during welding. Dry nitrogen also allows the installer to perform a preliminary leak test, collect moisture, and purge some contaminants. A vacuum process is then used to remove oxygen, nitrogen, and moisture that can affect the operation and damage the system.

Step 8: Condensate Drain Line Installation

The primary condensate line runs from the evaporator coil to a floor drain or condensate pump. A PVC pipe allows moisture to flow from your home when the AC is running. Condensate tubing or piping is secured and glued when installed to protect against flooding, and a safety overflow switch is connected to the evaporator coil’s secondary port. It’s also wired to the furnace control, so the system shuts off when tripped.

Step 9: Thermostat Installation

During air conditioner installation, a new thermostat is usually provided. If you keep your existing thermostat, the installer will check the connection between it and the new system. They can also install a separate thermostat if you want a smart system, for example. Your AC installer should also demonstrate how to use your new thermostat.

Step 10: System Testing

The technician will run the air conditioner for up to 20 minutes. During initial startup, the refrigerant will start flowing and the system will start to condition the air. It will feel warm at first. But you’ll soon start to feel the difference. All the while, the unit’s sequence of operation, thermostat function, and a range of parameters will be tested.

Schedule AC Installation with NEXGEN

Our experienced technicians can inform you about different types of air conditioners and what may be best suited for your home. They are trained to install any type of AC unit or brand as well as all necessary components. Comprehensive maintenance plans and warranties are also available. To learn more schedule an air conditioning installation in Southern California today!