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Frequently Asked Questions

Rex AC will answer any serious question you may have about maintaining your HVAC system to help you prolong the life of your equipment. Here are the long versions of answers.

If you have a question about your HVAC systems, it is likely that someone else has the same question. If you ask a question and we post it here, others can bennifit from your querry as well, as I will post both your question and my full answer here.  See the Rex Recommends page for quick answers.

How often should I change my filter?

Different environments have different needs, so it would depend on the amount of dust and pollens that are in your area as well as the type of filter you are using. HEPA filters trap very tiny particles and therefore would need to be changed more often than standard filters. Also there are filters designed to last longer and filter more air, these range from 1 to 4 inches thick. Your equipment determines the size filter you use, so if you're equipped for 1 inch filters, you should probably change them once a month. Electronic and UV light filter systems are also available and require special handling.

Why does my heater smell funny.

Properly installed and maintained equipment should provide you with clean filtered air with no contaminates and no smells beyond those of normal living. If you smell anything other than fresh air, it is an indicator of something wrong.  Leaking fuel can be dangerous and debris on the heat exchanger can produce noxious gasses. If you have flame blowback from outside wind or improper ventilation to the exhaust vent you may be getting exhaust fumes in your living area. If you smell any burning smell coming from your furnace or AC, turn off your unit and call a professional.

How long will a new furnace last?

As with all things, quality matters as does proper maintenance; the average life span of a furnace with yearly maintenance is about fifteen years, but this can be different based on the materials used, the processes used for assembly and other factors. I have been working on AC and Heating systems since the 1970's. I have seen systems fail in just three years, and other systems that have lasted over thirty. The difference is generally in the details, and in the maintenance schedule. I personally recommend Trane units as they have a longer lifetime than other systems I've seen and I recommend bi-yearly maintenance, in the Fall for heaters and in the Spring for Air Conditioning.

What is the proper way to fire up my furnace?

All furnaces produced in the last thirty years have electronic, automatic starters. If your furnace is not working, there is likely a safety trigger preventing it from starting. There are numerous sensors in a furnace which monitor the temperature, the electronics and power distribution to the blowers. A fault in these sensors will prevent the furnace from starting. This could be due to any number of causes.

If my heater quits will it cause my water pipes to freeze?

It can take an unprotected 1 inch water line about four hours to freeze at 30 degrees outside if there is no flow in the pipe. When water freezes, it expands, this will burst a standard pvc water pipe. If your furnace quits and you are afraid your pipes will freeze, turning on the flow of water, even just a slow trickle, will prevent the water in the pipes from freezing, but this will waste water. You can turn off the water at the source, and then open all of your water valves to allow the freezing water to expand without bursting the pipes. Once heat is restored, you can turn the water flow back on and close all the valves.

How is a swamp cooler winterized?

Water freezes and when it does it expands. Since swamp coolers work off of evaporating water, there is a water line going to your swamp cooler, and a drain coming from the coolers reservoir. The reservoir contains about twenty to thirty gallons of water. If this water is allowed to freeze, it can damage the cooler pan and the water level control system. To properly winterize your cooler, turn off the water supply to the cooler and drain the line if possible. Remove the pads and dispose of them or store them if they are reusable. Open the drain in the reservoir and remove all the water . Let the pipe drain and cover the unit with a winterized covering to protect it from the elements. A rubberized or plastic tarp cover, tightly sealed around the base of the unit is best. If you have it place the wind block over the swamp cooler vent or close the adjustable vent cover to prevent loss of heating through the open swamp cooler ducting.

Is the insulation on the copper pipes for my AC critical?

The insulation is to stop condensation from forming. Condensation occurs anytime moist air comes in contact with a colder surface. If your pipes are exposed to the air, condensation can occur and if there is enough moisture in the air, the condensation can gather and create a small flow of water. As these pipes generally run through the attic and walls of your building, such condensation can gather, and flow along the pipes, until they drip off at a low point. Therefore, in a place where you don't want water dripping such as indoors, they should be continuously insulated. If the insulation is torn, it should be repaired or replaced.

How do I effortlessly raise the humidity in my home?

Small one or two gallon humidifiers are available in most drug stores and department stores, but these systems are uncontrolled, and require constant human interaction. The amount of moisture added to the air by these systems are dependent entirely upon area they are expected to cover. So they may be great in a 30 x 30 room, but in a 10 x 12 they may produce too high a moisture level for comfort and health. With an in-system humidifier the air is constantly monitored and kept at a comfortable moisture level inside regardless of the humidity outside.

Do I need to winterize my air conditioning unit.?

Properly installed air conditioning systems are closed loops. The components that reside outside the home are designed to withstand most environments. If you happen to be where there is a lot of snowfall, and you have an outside air conditioning condensing unit, you may want to cover the condensing unit to protect from heavy snow, as it is possible to have heavy snow bend the fan blades on the condenser unit, but this is rare.

What AC unit brand do you recommend? And Why?

Trane. During my 45 years experience repairing air conditioning and furnaces, I have worked on nearly every brand, my favorite, for dependability and quality is Trane. They generally outlast other brands by 30 to 50%. They are built in Tyler Texas and they understand dealing with the heat. Trane sets a level of reliability that others don’t even aspire to.

What are the warning signs that my Air Conditioning or Furnace system is failing?

A properly built and installed Air Conditioning system is generally very quiet, and the air quality should be much cleaner than that of the outside environment. Some systems bring in outside air, but generally this is only about 5 to 8 percent of the total air quality, the rest is recirculated interior air, and unless you are performing some activity that is producing strange smells, your air should always smell clean and fresh, if you are smelling strange smells, you should shut down your system and have it inspected. Strange sounds are even more destructive, and could indicate imminent catastrophic failure. Shutting down the system prevents further damage

Doesn’t a dirty air filter work better than a clean one?

No. Air filters collect dirt and pollen particles from the air, as they do so, the air flows around the collected particles. This is why filters generally build up a very even layer of dust. As the areas where air can flow is blocked by dust grow, the amount of air flowing through is reduced, at the point where the air flow is reduced by 10%, you are now cleaning only 90% as much air as before, so less dust and pollen are actually being moved through the system. When the filter is blocking 20% of the air flow, the coils are more likely to cause condensation, as condensation increases, air flow is reduced even more, and could lead to coil freeze up. Filters should be changed as soon as air flow is noticeably affected.

My AC unit outside has a fan in the center, so the outer edges are not important, right?

Air conditioning works by moving heat from one place to another, this is done through the condenser unit outside your home. As the cooling chemicals move through the condenser, air is blown across the fins surrounding the tubes, this removes the heat, which causes the chemicals to change from a gas to a liquid, which is then pumped inside your home to similar coils, giving you cooling. If the coils around the unit are blocked by weeds, grass, pollen, spider webs etc., the amount of cooling is reduced, and more power is required to accomplish the desired comfort level. This in turn reduces the usable life cycle of your equipment.

Can I power-wash my coils?

Never use high pressure washers on your air conditioning unit. The coils which transform the cooling chemicals from a gas to a liquid are made of aluminum and the fins on those coils are also of aluminum and very thin. The fins are required to transfer the heat from the coils to the air. It takes very little pressure to bend these fins, and once they are bent, they prevent the flow of air across the coils. There are special brushes and soaping formulas you can use to gently clean the fins, and even tools designed to help reposition bent and altered fins, as it is the most critical part of your cooling system.

Do I need to have my ducting cleaned?

If you live in an area with a lot of airborne dust and pollen, you likely have a collection of such dust in your ducting. No more so than would happen on your furniture, less even as the moving air through your ducts likely moves some of it out through your vents. But, how often do you get inside and dust your ducts? If your unit is more than ten years old, you likely have a thin layer of dust accumulated in your duct work and may want to consider having it professionally cleaned. If your unit has been run without a filter, then the dust level is likely to be much worse in the ducts. An easy tell is if there are dust tracks around your registers.

Why should I use a programable thermostat?

It is much less difficult to maintain a temperature than to change the temperature. If you allow your home to drop twenty degrees before attempting to change the temperature, it takes more energy to reach comfort level, than it would have had the house been kept at the comfortable level. If you are going to be gone for many hours, it is not efficient to keep the home comfortable when no one is there, a programmable thermostat can bring the house to comfort level starting just before you are scheduled to arrive. With internet enabled thermostats you can control your home environment from anywhere you have internet access, from a computor or a smart phone.

My swap cooler has salt buildup, how do I fix it?

Swamp coolers work by evaporating water from your home tap water. This is just like boiling water on your stove, as the water evaporates, the salts become more concentrated. Putting white vinegar in the water will help break down the salts, but, that is not enough, after about an hour you need to then drain the salt and vinegar water out of the unit, and clean it. Then refill the reservoir with fresh water. When you begin to see the salt beginning to accumulate on the panels, clean the reservoir using white vinegar and replace the water again. You can also add an inline filter on the water supply line.

Do I need to have my unit checked yearly?

Air conditioning and furnace units are complex mechanical and electronic devices, which like your car or any other complex machine can over time and with use have certain parts wear out, get out of alignment or simply short out. If these parts are allowed to continue functioning while in a failing state, they can damage other components. Examples are capacitors failing, fan motors becoming unbalanced, exhaust lines becoming blocked, coolant leaking, flame jets becoming fouled, limit switches failing, air flow sensors getting clogged, wires getting damaged, and many others. Catching these things in their early state can prevent greater damage at a later point.

Can I cover my floor vents?

Proper air conditioning and heating systems are calibrated for the size of home or office they service. This means a mechanical designer/engineer calculated the airflow needed for each room of your home and calculated the proper size of ducting, register, air flow and heating or cooling ability to provide an equalized environmental condition. Most registers are adjustable, to allow reducing the amount of airflow to each room based on the fact that different people enjoy different levels of comfort. But, cutting air flow in one area will increase the air flow in other areas, so, unless an area is completely unused, it should still have some air flow. Also, if you are adjusting registers to make your system work properly, you likely need your system checked.

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