What should you do if your central air conditioner is not working properly? You can fix some problems yourself. will need the attention of a heating and cooling contractor. If your central air conditioner will not run at all, here are three troubleshooting steps you should take before doing anything else: These are simple steps, but they can save you an embarrassing and potentially expensive service call. Here are a few other common central air conditioner problems: Like most equipment with several moving parts, AC units can make several noises, some louder than others. For instance, a grinding noise can mean a problem withA rattling noise could be caused by something minor like loose cabinet screws, but it can also be a sign of a worn compressor. And a slight hissing noise could be a sign of a refrigerant leak. Improper airflow due to a dirty filter can cause the air conditioning unit to freeze. Dirty filters can cause a variety of problems, so it is important to clean or replace your filter regularly.

A damaged blower fan can also cause the coils to frost up, as can a faulty control relay. If your central air conditioner is low on refrigerant, chances are good that it has developed a leak. If it is leaking, simply adding refrigerant will not solve the problem. You will need a trained technician to repair the leak and refill the refrigerant. To perform efficiently, a refrigerant charge should conform to the manufacturer's specifications. This is another problem that can be caused by dirty filters. If your central air conditioner is not producing enough cold air, the first thing to do is check the filter and clean or change it, if needed. Another possibility is that your unit is low on coolant. If so, you’ll need to contact a licensed repair technician to check for leaks and recharge the system. There are a few possible reasons for this problem. A unit that runs for a very long time may be too small for your house or may not have beenAnother possibility is that the thermostat is on the wrong setting or needs new batteries.

A bad relay switch or a unit that is low on refrigerant can also prevent it from shutting off. And yes, a dirty filter can contribute to this problem, as well. Usually, keeping the A/C components clean can help to prevent many problems. Dirt may make the compressor or fans fail before they should. clean or replace dirty filters to keep your unit functioning properly. should an ac window unit be levelAlways keep the manufacturer's manual handy and if you don't have one, requestwhat size ac unit for 100 square feet one from the manufacturer.what's the best ac unit for a home 4,217 posts, read 5,568,110 times 2,148 posts, read 2,369,904 times Originally Posted by NorasMom When I lived in an apartment some years ago before I got married, the unit had a heat pump/with an air conditioner.

When it was low on freon it would not produce cold air - maybe cool - for a while anyway, until it was serviced. How long has it been since the unit has been serviced? Do you need to change your filter? I think it needs to be looked at. The AC should work to keep you cool inside no matter how hot it gets inside. I would shop around and do some homework if you end up buying a home of your own - and get something efficient and in proper working order. There's no reason it shouldn't manage if operating properly. Now I'm not trying to get mine super low. I'm happy with 77. But I can easily get to 77 on the hottest 90+ days (we hit 100-ish yesterday) and it still cycles on and off as usual and gets to that temp easily. And actually, because of how I have the air vents opened or closed, some rooms get cooler than that, like the bedroom I sleep in. Is it running constantly and never getting down to the set temp? FYI unless the thermostat itself is broken you won't get it cooler any faster by turning it lower.

If it is running constantly and never getting to the set temp then it needs to be serviced most likely. If it gets to where the thermostat is set and cycles off, but it's still warm throughout the house then the thermostat may be way off and then at least cranking it cooler would be good for something. If it gets to the set point and cycles off but only certain extremities of the house are hot, then you should try closing certain vents off that are closer to the thermostat so that the cold air blowing out doesn't shut the A/C off prematurely. It's amazing how often that little detail is overlooked. No matter what an A/C checkup from a qualified tech is a good idea. Since it's a rental, I would take it up with the landlord. Really, it should work. There's no reason it shouldn't cope even with the hottest days. My house gets no shade from the south so sun beating all afternoon and still cools down. If a properly functioning and adjusted A/C still doesn't cool the house, it's most likely too small for the conditions.

8,923 posts, read 33,173,370 timesMy house was built about 30 years ago and appears to be decently insulated given my low gas heating bills compared to some friends I know with older houses. It's easier to heat than A/C though apparently, or just more expensive to A/C I guess. I guess my thought though would be I find it difficult to believe everyone mentioning this problem has a poorly insulated house. Really depends upon the age though I guess. Older houses would be more suspect unless someone has specifically remedied the problem. I was surprised to learn that a house in Massachusetts built in the late 60s still didn't have any insulation in the walls (dunno about attic). Apparently even then nobody thought it would ever cost significantly more to heat (it heats with oil). I grew up in a house circa 1972 in West Virginia; that house had fiberglas insulation throughout the walls and attic.Posted on Oct 16 2009 by It's important to provide a path for air that wants to get back to the furnace.

Installed in a bedroom ceiling, this grille is connected to a similar grille in an adjacent hallway by a large-diameter duct. The jumper duct provides a pathway to help bedroom air find its way back to a large return-air grille in the hallway. The sign explains the purpose of jumper ducts to potential home buyers visiting a model home in a Pulte development in Las Vegas. In homes with a single central return-air grille, return air often struggles to find its way back to the furnace. The result: room-to-room pressure imbalances that lead to uneven room temperatures, comfort complaints, higher energy costs, and even moisture problems in walls and ceilings. When a furnace comes on, heated air is pushed through supply ducts to registers in each heated room in a house. If the forced-air system is properly designed, the house includes return-air ducts to convey air back to the furnace to be heated again, in a kind of continuous loop. While most HVAC(Heating, ventilation, and air conditioning).

contractors install ducts and registers to deliver conditioned air to every room in a house, they often neglect to provide an adequate return-air path from each room back to the furnace. Most rooms don’t have a return-air grille; instead, there’s often just a single large return-air grille in the living room or a central hallway to serve the whole house. That means that all of the air needed by the home’s forced-air system has to be pulled through that single grille before it can be heated by the furnace or cooled by the air-conditioning system. Isn’t one big central return good enough? Here’s what can happen when a forced-air system doesn’t have adequate return-air pathways: When the furnace is operating, it pushes conditioned air into each bedroom. If the bedroom doors are closed, there’s no easy way for the air to get back to the return-air grille in the hallway. As a result, each bedroom becomes pressurized, forcing air into cracks in the bedroom walls and ceiling.

During the winter, this humid interior air can contact cold surfaces in the wall, leading to hidden condensation and even mold. Meanwhile, the big return-air grille in the hallway is starved for air. Since the hallway and living room are now depressurized, air is pulled from the attic into the hallway through cracks in the ceiling. This New Door Design Solves an Old Problem Return to Sender – HVAC Return Pathway Options Perfect Balance Makes the Cut New Green Building Products — March 2011 Jim Cummings, a senior scientist at the Florida Solar Energy Center (FSEC), has measured pressure differences arising from unbalanced forced-air systems in over 200 Florida houses. “The typical positive pressure in a bedroom with a closed door is on the order of 15 pascals — ranging from a low of plus 5 pascals to over 45 pascals,” said Cummings. “That’s a tremendous amount of pressure. Air is being pushed out of these rooms into the attic and through the walls towards the exterior, while the central zone of the house is depressurized and pulls air in from the attic.

A lot of this uncontrolled airflow is actually an exchange between the house and the attic.” During the winter, the air that is pulled from the attic is cold, and the cold air increases the heating loadRate at which heat must be added to a space to maintain a desired temperature. During the summer, the air that is sucked indoors is hot and humid; this infiltration increases both the sensible and latent loadCooling load that results when moisture in the air changes from a vapor to a liquid (condensation). Latent load puts additional demand on cooling systems in hot-humid climates. on the air conditioner. There are three possible ways to solve the pressurized-bedroom problem. Each bedroom needs either: A return air grille ducted back to the furnace; A through-the-wall transfer grille connecting the bedroom and the adjacent hallway; A crossover duct (a jumper duct) connecting a ceiling grille in the bedroom with a ceiling grille in the hallway. The best of these three solutions is the most expensive: install a return grille ducted back to the furnace in every conditioned room of the house.

Through-the-wall transfer grilles are a cheaper solution, but they have a major drawback: noise transmission. Homeowners don’t want people in the hallway to hear what goes on in the bedroom. Most contractors who bother to address the pressurized-bedroom problem install crossover ducts. As typically installed, a crossover duct connects a ceiling grille in each bedroom with a nearby ceiling grille in the hall. Although a crossover duct will transmit sound, it provides more muffling than a through-the-wall transfer grille. However, crossover ducts have all of the disadvantages of any attic duct. To prevent unacceptable heat loss or heat gainIncrease in the amount of heat in a space, including heat transferred from outside (in the form of solar radiation) and heat generated within by people, lights, mechanical systems, and other sources. See heat loss., it’s best to limit the installation of crossover ducts to homes with cathedralized attics — that is, homes with insulation that follows the roof slope.

A variety of methods have been proposed for sizing transfer grilles and crossover ducts. According to Cummings, a transfer grille should provide 70 square inches of free area per 100 cfm of supply air ducted to the room; Cummings’ recommendation is sometimes called the “FSEC guideline.” Cummings says, “That guideline is based on calculations, confirmed by experiments in the field.” Some engineers prefer larger grilles. According to Paul Raymer, the chief investigator at Heyoka Solutions and former president of Tamarack Technologies in West Wareham, Massachusetts, a manufacturer of through-wall transfer grilles, it’s best to add 40% to the FSEC guideline. “We figure that with two grilles, instead of 0.7 square inch per cfm of supply air, you need one square inch, to account for the resistance of the two grilles,” said Raymer. Armin Rudd, an engineer at Building Science Corporation in Westford, Mass., advises that transfer grilles need only 54 square inches of free area per 100 cfm of supply air.

While Cummings prefers to keep room-to-room pressure differences at 2.5 pascals or less, Rudd is willing to accept room-to-room pressure differences of 3 pascals. (The 2.5-pascal standard has been mandated by the Florida Building Code since March 1, 2002; in almost every other state, building codes are silent on the issue.) Rudd’s rule of thumb assumes that the average bedroom door has a 1/2-in. by 32.-in crack at the bottom — a crack that contributes to solving the pressurized-bedroom problem. According to Rudd, a 6-in. round jumper duct is adequate for a bedroom with 75 cfm or less of supply air. An 8-in. duct can balance a room with 120 cfm of supply air; a 10-in. duct balances 175 cfm of supply air; a 12-in. duct balances 225 cfm of supply air; and a 14-in. duct balances 300 cfm of supply air. Why can’t I just undercut the door? Undercutting a bedroom door won’t solve the pressurized bedroom problem. Raymer points out that even a very large gap — a gap of 1 inch between the finish floor and a 30-inch-wide door — can handle only 47 cfm of return air at a maximum 2.5 Pascal pressure difference.

That’s adequate for only a tiny room measuring about 75 square feet. There’s another problem with door undercuts: they’re not under the control of the HVAC contractor. The final gap depends on the choice of finish flooring and the way the door is hung; these details are usually determined by the finish carpenter, long after the HVAC contractor has left the job site. Two product manufacturers have come up with solutions that allow air to be transferred through an interior door; the products are the Perfect Balance grille and the VanAir Design door. First, design the system; Of course, even well-designed jumper ducts will only work properly if the forced-air system is set up properly. When the HVAC system is commissioned, the supply airflow to every register in the house should be verified and individual balancing dampers adjusted, to be sure that the system meets the design air flows shown in the Manual D calculations. Although residential HVAC system commissioning should be routine, it is, alas, still rare.