I have two AC Units. One for upstairs and one for downstairs. The upstairs one works just fine but not the downstairs. So, i did a test by turning both units on and went outside to compare the two units. The upstairs one works fine and blows out warm/hot air, but the downstairs one seems to blow out cold air compare to the working unit. These two are not heat pumps. They are both AC units. Anyone know what is wrong with my downstairs unit? BTW: I had the HVAC guy come out to check it 3 years back, and he added refrigerant into the system. It worked for a week or two after he left, then it's back to warm air again. Would this be a leak of some sort? Because of the need to capture the refrigerant and licenses to get the refrigerant in most places, this typically isn't a DIY job. The fact that the outside unit is running and air is blowing inside suggests that it's not a problem with the thermostat. Check the breaker, air filters, and any other easy to access components for obvious problems.

Beyond that, there are a lot of possible issues: No refrigerant or not enough Controller has failed or wiring has become disconnected Inside coils have frozen over Since the first two are the most likely and either will need a professional to repair, you may as well get one out to diagnose the problem for you. It's either a dirty unit or a capacitor problem. If the unit is very dusty you need to clean out the dust to let it breathe. If the capacitor went bad, when you look at it the top will be bubbled up. Most likely it's the capacitor. Change your filters: a dirty filter is what an AC mechanic loves; it's money in the bank for him.Browse other questions tagged repair hvac air-conditioning or ask your own question.Now that we have seen how an air conditioner does the work, let's look at the mechanics involved. We can see that there are two main systems in a roof top air conditioner, the sealed refrigeration system, and the air handling system. In addition to these systems, there is, of course, the control system (thermostat and fan switches).

For the sealed system, all brands, Coleman, DuoTherm, Carrier, Intertherm, and others, work the same, using the basic principals of refrigeration. In the sealed system, the main component is the compressor- which, by itself, is not serviceable, but there are some components that are external to it which are serviceable. For now, let's look at the most common and easily repaired problems.central air conditioning unit not cooling problem The one major compromise that roof top air conditioners all have in common is the fact that they all have to route both the return and supply air through a standard 14" by 14" cutout in the roof. air conditioner unit won't workThis is even more amazing when you realize that the average 13,500 btu air conditioner has just over 1 ton of cooling capacity- a 15,000 btu model is around 1 1/4 tons. portable ac units for your vehicle

A motor home or large trailer that has two 15,000 btu air conditioners has 2 1/2 tons of air conditioning- or enough capacity for many houses. The two most common complaints are "Not cooling enough" and leaks. Let's look at "not cooling" first. Not blowing cold air. The first thing to determine is if the compressor is coming on. If it isn't, it is likely a control problem with the thermostat or relay board (if you have a wall mounted thermostat). If the compressor is coming on, then you need to look into the airflow of the unit. Whether or not the compressor is coming on, you need to check the voltage. Like every appliance on board, the air conditioner needs adequate power to operate. If the voltage is 110 volts a.c. or below, the effectiveness of the unit will start to suffer. After verifying correct voltage, we need to look at how the air conditioner does it's job- it requires adequate air flow over both the inside (evaporator) and outside (condenser) coils. If the air filter is clogged refrigerant will not be able to pick up enough heat from the inside air, and if the condenser coils are blocked by leaves, it will not be able to give off enough heat to the outside air.

Most RV rooftop air conditioners have washable filters, which can be vacuumed or rinsed off in a sink to clean. If you are in summer weather where the air conditioner is running 24 hours a day, the filters should really be at least vacuumed once a week. Note that if the filters have been neglected, the evaporator coils probably need cleaning as well. These can be seen when you remove the air filters, and possibly the inside air box. Likewise, the condenser coils can be seen after removing the upper shroud. Note that some air conditioners draw air in from the back, and some blow air out the back. You will need to determine which your is, or just check both sides of the condenser. An unavoidable drawback to being able to mount an air conditioner in a 14" by 14" roof vent cut out is that both the supply air and the return air are in very close proximity to each other. This can be a problem if the two are not sealed well from each other- if the cold supply air can recirculate into the return side, the evaporator coil can easily freeze up, plus that is cold air that is just going to waste.

Note that this is normally more of a problem with ducted type air conditioners than the standard exposed air box type, but it is something that you need to be aware of, in all cases.A fairly easy way to check is to simply, carefully put your hand into the return air duct and feel for cold air. If you can feel cold air, you need to take care of the air leak. The last problem we will talk about is heat gain. One compromise that most RVs make is in the insulation department- after all, if they had 6" thick walls for good insulation, there wouldn't be much living room left, so.. In very hot weather, and direct sun, the amount of heat that the RV will pick up may be greater than the amount of heat the air conditioner will pump back out. In this case, shade is the answer! Whether you use an awning, or an oak tree, in very hot weather, keeping the direct sun off of the RV will greatly increase your comfort.There’s nothing worse than sitting in your home and realizing that your air conditioner is blowing hot air--especially during the sickeningly hot summer months.

Even though It’s not summer yet, you don’t want to look for answers for why your air conditioner isn’t working when you’re burning up inside your home. It’s best to know the reasons ahead of time so you’ll know how to avoid them or when to call a professional. So why is your AC blowing hot air? Here are 4 common reasons: Ok, this might be a huge “duh” but if you’re getting hot air, you might have accidentally flipped your thermostat to “heat” mode. It happens to all of us. If that’s the case, switch it back to “cool” and you’re good to go. Chances are, your thermostat is set to cool, and you’re still getting hot air. The cause could be a dirty evaporator coil caused by a dirty air filter. This keeps your air conditioner from properly cooling your home. You can change the filter, but you'll need a professional to clean the evaporator coil. Walk outside and look at your air conditioner’s outside condenser unit. What do you see?

Is there anything blocking the condenser coils air flow? Are they blocked with dirt and debris? If so, this seriously impacts your air conditioner’s cooling ability. Cleaning the condenser coils needs to be a regular activity during the summertime. This is the usual culprit. Your air conditioner needs a proper refrigerant (usually Freon) charge to cool your home. So a Freon leak can leave you feeling the heat since you’ll have a complete loss of cold air. You can tell if your air conditioner doesn't have enough Freon if ice forms on the inside and outside units. Getting a Freon charge is best left to a professional. Keeping an eye on these problems will not only will this keep your air conditioner from blowing hot air, it will also prevent a costly breakdown. And the last thing you want is a breakdown during summer. So it only makes sense to get preventative maintenance done during the spring before it gets too hot. If you live in the Atlanta, Georgia metro area, give Coolray a call.