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.“Let comfort be your guide,” says Tom Hutchinson of Hutchinson Plumbing Heating Cooling. Air conditioning is all about comfort, so the simplest way to evaluate your system is to ask: Am I comfortable?Air conditioning and HVAC units don’t last forever — 12 years is an average lifespan — and the moment they fail is usually when you need them the most.

The good news is that not every system malfunction spells total doom. Many nuisances are so cheap and easy to fix, you’ll kick yourself for not doing them sooner.Possible cause: Often, the most likely culprit is the easiest to remedy: The thermostat isn’t set correctly, or power isn’t reaching the AC unit.The fix: Make sure that the thermostat is set to AC or “cool,” that the temperature setting is correct, and that the battery is fresh. ac unit for roomSecond, check the circuit breaker: It could simply be a tripped fuse. prices of ac unitCost: FreePossible cause: ”Airflow is paramount to comfort,” notes Hutchinson. best a/c unit for floridaIf you aren’t comfortable, the problem usually can be traced to issues with airflow.The fix: Change the filter.

(You should do this as part of regular HVAC maintenance anyway.) Depending on the quality of the filter, the amount of people living in the house, and if there are pets, the filter should be changed every 30-60 days. Outdoors, make sure there’s at least 24 inches of clearance on the sides and 5 feet on top of the unit. Also, check to make sure there are no obstructions to the home’s cold air returns and registers.Cost: $5 to $20, depending on the filter.Possible cause: A spike in operating costs typically signals inefficient operation. After a dirty filter (warning sign #2), the most likely culprit is a choked condensing coil. Located within the outdoor unit, the coil has countless cooling fins — much like a car radiator — that can accumulate dust and debris. The fix: Call out a pro for a spring tune-up.Cost: $75 to $150Possible cause: Rattling, buzzing, or ticking? The good news is that the cause might be little more than a loose screw. The bad news is that it could be caused by a bum blower motor (indoors) or bent fan blade (outdoors).

The fix: If you’re lucky, a simple tightening here and lubricating there will fix the problem. If not, you might require a new fan motor or fan blade.Cost: $75 to $150 for an inspection and tune-up; $150 to $750 for a new blower motor.Possible cause: Improper placement of the thermostat can wreak havoc on one’s comfort. The unit might be in direct sun, too close to a register, or near a hot oven. Also, a remodel might have you spending more time where the thermostat is not.The fix: Relocate the thermostat.Cost: Free if you’re handy (and plan on reusing the same unit); up to $250 for a new programmable unit, plus another $90 for an electrician to install it.Possible cause: During normal operation, the system generates moisture in the form of condensate. That water collects in a pan and flows out a line either into a floor drain or condensate sump basin. An accumulation of water signals a blockage or disconnection of the tube.The fix: Inspect the tube for crimps, clogs, and disconnections.

Also, if the water flows into a sump basin, ensure that the sump pump is in good working order.Cost: Free to clean out blockage; $20 to replace the tube; $40 to $110 for a new condensate sump pump.Possible cause: The refrigerant lines aren’t insulated.The fix: The outdoor unit is connected to the indoor system by two copper refrigerant lines, which should be covered with insulating sleeves. Make sure that they are. Also, the system may need its refrigerant re-charged.Cost: $5 for insulating sleeves; up to $150 for a system re-charge.Possible cause: Burnt-out compressorThe fix: If the compressor fails, the unit won’t run. The only fix for this is a costly replacement of the equipment, which includes various small parts, new Freon, and labor.Cost: $600 to $1,900. It might be wise to replace your air conditioner if it’s more than eight years old, or if the estimated cost of repair is more than 50% of the cost of a new unit.There is ice on my AC unit. May 26, 2012   Subscribe