5 Things You Should Know When Installing an Air Conditioner

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5 Things You Should Know When Installing an Air Conditioner

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With the heat of the summer approaching, you may be looking to buy a new Central air conditioner.

Here are some tips to help you get the job done right! Today’s residential air conditioning systems are not as simple to install as they may appear.

Merely connecting all the tubing and wiring is just the beginning.

Beyond that, there are several important steps in the installation that can either make it or break it for you!

Here are 5 very important things that need to be done properly for your new air conditioner to last a long time.

This is how we do it day in and day out.

Number 1 - The installation of the evaporator coil (usually above your furnace) is a crucial part of a good install.

It must be installed in a way that directs all the air flowing out of your furnace, through the new matching evaporator coil.

This ensures that no air is flowing around it.

Also, the air leaks in the sheet metal work should be sealed with tape or sealant made for this purpose.

In the field, we often see an installation where the coil is mounted so that much of the air is flowing around the coil, which was never right to begin with.

We use 26 Gage Galvanized Metal Angle for this purpose because we come prepared to do it right.

Number 2 - The airspeed needs to be set at approximately 350 to 400 CFM per ton for air conditioning to work as it was designed to.

This is a very important step that is needed later when testing the level of “charge in your new system.

" Also, be sure to know the type of restrictor device your system has.

Is it a piston-type or a TXV (THERMOSTATIC EXPANSION VALVE)? It is not unusual, on a service call, to see that an installer has left the furnace fan speed set in the factory position, which is usually too high and a good indication that the charge was never checked when the AC was installed.

There can be a more negative effect on piston-type systems if the airflow is too high or low.

Systems equipped with a TXV also need to have the “bulb” installed in the correct location and orientation.

So many times, when removing someone’s old system we see the bulb still sitting in the shipping location, which means it was never working right from day one.

Number 3 - With today’s systems running on R410a refrigerant, it is more important than ever to have inert gas such as NITROGEN flowing through the copper tubing.

This is used to move the refrigerant from the outside unit (condenser) through the inside unit (evaporator).

The reason for this is that oxides can occur from the brazing process, and they contaminate the new system before it even starts.

This result can result in poor performance and a short life span of your new air conditioner.

Number 4 - It is important to test your new system for leaks before starting it up for the first time.

This is a two-part process that we follow on every installation.

The first step in this process is to pressure test all the welded joints, and since we are using NITROGEN for brazing, we just leave it connected to your new system.

Then, we pressurize the evaporator and new copper line welds up to 200 PSI for a few minutes.

If there is a leak, it will show on the gauge, and you may even be able to hear it if it's big enough.

It's not uncommon to have a small leak at this time because sometimes the position of the joint is difficult to access.

So by using NITROGEN as a first step, the system can be pre-approved as leak-free.

Number 5 - The final step we take, for all new installations or on any repair calls, is to use a Micron gauge to prove that the new system is 100 percent leak-free.

We pull our vacuums down to 250 microns using a properly calibrated digital gauge.

You cannot pull a deep vacuum, such as this, with any kind of small leak or non-condensable in the lines.

Once we establish the deep vacuum, then and only then, do we release the refrigerant from the new AC condenser that comes with a factory charge, which is usually sufficient for installations.

The final part of the start-up process is to measure the charge to ensure it is within the manufacturers' specifications.

We use digital gauges, which measure all the important things needed to be certain the system is right on the money, such as using a superheat calculation for piston-type systems and sub-cooling for systems equipped with a TXV.

We usually end up either having to add a bit of refrigerant to the system or remove a bit of refrigerant depending on the length of the tubing or other variables to dial in the charge just right.

Sometimes it takes an extra bit of time but now you are ready to enjoy many years of trouble-free air conditioning to keep your home comfortable through the hottest days of the season.

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