Shelton’s Pride takes great care and time designing and installing all different types of duct systems. We train all of are technicians and installers through several different outside agency to allow the best mentoring possible.

Most homes are equipped with new construction or builders grade duct systems, which most of the time are incorrect and are costing you extra money and less comfort in your home. Shelton’s Pride can usually use most of the ducting that is provided from the builder. We usually just need to make some modifications to make sure there is enough return air and that we can get enough air pressure throughout the duct system. We can achieve this by adding balancing dampers and correcting the return air ducts or increasing the return air grills on vertical units. We take out  remote plenums or triangle boxes in the structure to insure correct air flow. These are used to save money for the builders. The builders do not want to run straight ducts runs with dampers, because it is more expensive for the ducts.

All duct system should be designed according to the ACCA Manuel D. In basic terms all of the ducts are designed according to pressure drops. Every duct has its own psi drop depending on friction loss, length, turns, grills, etc. After designing your duct system you need to match it up with the proper blower fan with the correct static pressure  ability to overcome the pressure drop in the duct system.

Most builders due provide Manuel D calculations, but do not test the systems after installing them. This is crucial because no duct system is installed in a lab atmosphere, it installed in a home with framers that don’t even take in  account the duct system.

To sum it all up, you should have an air diagnostic test on your home or structure to insure you are getting the correct airflow that was promised by the builder. This should be performed by air balance certified technician with the correct tools. See blogs about who is qualified to perform there test.

The two most common ways for a do-it-yourselfer to find a leak is to (1) visually inspect the system for telltale oil stains, or (2) add a can of “leak detector” to the system and then look for the presence of the colored dye around hose connections and fittings.

When refrigerant leaks from the system, it immediately evaporates into thin air leaving no trace except possibly the compressor oil residue that leaks out with it. Wet oily areas around hose connections and fittings and/or greasy streaks radiating outward around the compressor clutch or on the underside of the hood just above the compressor are good visual clues to where the leak is.

Leak detecting dyes will often reveal tiny leaks that might escape visual detection. Some are fluorescent and require illumination with a special light before you can see them. Even so, even dyes can fail to show you where a leak is if the leak is in the evaporator (located inside the heater/defroster plenum under the dash) or in a hard-to-observe or hidden location.

Most professionals use an “electronic” leak detector that reacts to the presence of refrigerant in air. Such detectors are extremely sensitive and can detect leaks as small as 1/4 oz. of refrigerant per year!

Fixing Leaks

Once a leak has been identified and pinpointed, it should be fixed. Don’t waste your time on “stop leak” products because they seldom work.

Leaks should be fixed for three reasons. One is because leaks allow air and moisture to enter your A/C system. Moisture can react with refrigerant to form corrosive acids and sludge that can damage the compressor, plug up orifice tubes and/or eat pinholes in evaporators and condensers. Another is because refrigerant is expensive. It may seem cheaper to keep recharging your system with additional refrigerant instead of having the leak fixed, but in the long run it won’t be as the cost of R12 refrigerant continues to rise. Third, R12 refrigerant is an ozone-depleting CFC. When it leaks into the atmosphere, it drifts up into the stratosphere and destroys ozone that protects us from the sun’s harmful ultraviolet radiation.

Before any attempt is made to repair a leak, any refrigerant that’s still in your system should be recovered and recycled. All service facilities that do A/C work are required by law to have such equipment.

Once the old refrigerant has been pumped out of your system, it can be opened for repairs. The desiccant (crystals that absorb moisture and help protect the system against moisture contamination) in the accumulator or receiver/drier should also be replaced if the system has lost all its refrigerant or must be left open for more than a few hours for repairs.

After the leak has been repaired, the system must be connected to a vacuum pump to purge it of all air and moisture before it is recharged with refrigerant. Leaving air and moisture in the system will greatly reduce the cooling efficiency of the system and will lead to the formation of damaging acids and sludge.

It’s also important to replace any compressor oil that was lost due to leakage or parts replacement. Use the type and quantity specified by the vehicle manufacturer.

CAUTION: Using the wrong type of compressor oil or too much or too little oil may result in compressor failure