a/c system not blowing cool air, just air is blowing

Question

Walter Reeves · Answer

Is the big fan in the compressor out back blowing air or is it still?

Sem I · Answer

Thanks! I just went outside and checked it, it's not working. Only the second fan cooling the rooms upstairs is working.  It's weird because air is blowing from SOME  of the vents downstairs but not all, how is that?

Walter Reeves · Answer

First thing to check is the circuit breaker that controls the compressor. It should be clearly marked in your circuit breaker box.

If it's ON and the compressor still doesn't come on, you need to hire a professional. Could be a problem in the thermostat or the compressor unit could be bad.

Woodbridge Environmental Tiptophouse.com · Answer

As Walter said, you need to check the outside breaker or fuse box on the condenser unit. These are typical causes for outdoor units not working.
Also depending upon the thermostat you have, some have a delay switch built in that prevents the unit from running for a short period of time and if the thermostat becomes faulty the unit never operates. 
Another reason is low refrigerant gas in the system.  If you find that you needed to add gas to the system every year or so a leak may have caused the refrigerant to leak out to a point that the safety pressure switch within the unit has shut it down to prevent damage to the compressor within the system.

Now with the issue of some vents blowing and some not.  I assume you only have one cooling thermostat?  Or do you have more then one?  How many outdoor units do you have also?  If you have two or more cooling stats and only one outdoor unit, your system is zoned. When that happens, one of the zone thermostats becomes the main switch that determines if they are all set for cooling or all set for heating mode.

Normally the one that is located in the dining room or main hall controls the functions of the system.. Be sure that its set to cooling mode and then check again.

Some zone systems require that a switch elsewhere be turned to summer mode, or cooling mode.  This switch is oftentimes found at the top of the basement stairs or next to the heating and cooling system.

So if you have a zoned system that could be the reason why only a few locations are not working as they should.

Provide some more information about the system, such as number of thermostats, number of outdoor units. Age, location of cooling fan, attic or basement/crawl   Is it connected to heating system or independent of the heating system. etc.  Knowing more can help figure out what you need to do before you call a service tech in.

Sem I · Answer

Thanks both, I had checked the breaker when I got the post from Walter and it was off.  Now it's working, we have cool air blowing.

Woodbridge Environmental Tiptophouse.com · Answer

One thing to remember, if the weather is cooler, below 60 degrees and you want AC, the breaker must be on for at least 24 hours as there is a heater located in the outdoor unit that boils off liquid refrigerant from the compressor preventing it from damage when it starts. 
Glad you are up and running!

HouseFixer.info · Answer

HVAC in my opinion is not a task for DIYers.  You have several potentially dangerous hazards for those that are not trained in this trade.  Please call a licensed HVAC Contractor for this.

Sem I · Answer

Can someone tell me why air is blowing (not cool air, just air) from the vents when the hvac unit is not operating, as if turned off. The thermostat is on auto cool.

Sem I · Answer

waiting for an answer, thanks.

Woodbridge Environmental Tiptophouse.com · Answer

SEM I If the fan blower is running and the unit is not calling for cooling. ( temp is set higher then room) and your fan switch is set on the auto position. There can be two things that are causing this. 1. The blower relay is stuck and needs service. Or 2. There is a fan limit and switch control that turns on the blower when the heating system comes on. If the setting on the on side of the switch is set to low just the hot air in the house can be enough to trigger this relay to operate the fan. When this happens it normally runs the fan for short bursts and turns off again until it heats back up again. 
If your system is not running on the fan limit control The relay, or depending upon the furnace or blower that is installed the printed circuit board could be faulty and require replacement. 
In any case this type of repair should be left to the professional. Repairing a printed circuit board or attempting to replace can be difficult if you do not have the necessary experience in this type of repair.

Sem I · Answer

Thanks for the reply. I got sick on top of the house being hot. So here is the situation, the unit outside is not running, the thermostat is on auto and cool, the furnace in the basement is running continuously even when all the thermostats were turned off, and the vents inside blowing air, just not cool air.

Bijan Air Conditioning · Answer

i do not answer you to do the job your self you need to call a licensed contractor please, it cost you cheaper in long run .

Woodbridge Environmental Tiptophouse.com · Answer

Sem I, Your questions are not making any sense. 
Do you have two systems? 
Is one working and one not?
Assuming two units and with both off one keeps blowing air even when everything is off? 
But if the system is on and calling for cool air does the outdoor unit operate?

I think you need to seek and advice of a pro on this. If the breakers are on in the basement, and the fuses have not blown located in the outdoor disconnect switch that connects the outdoor unit to the power supply, you need a pro to find the issue and fix. Other than fuses or breakers there is really nothing you can work on yourself safely.

White Oak Studio Designs · Answer

Air Conditioner Experts….
I have a 950 sq. ft. building built new in 2001 (w/forcedair and a.c) on a cement slab/no basement. I think there might be a problemwith the a/c unit. It does not seem to be removing the humidity from thisbuilding so I am using a dehumidifier 24/7 and that is removing a LOT ofmoisture every 24 hrs. We live in rural MI and have a well, septic/drain fieldsand county drain system (s) here.
We have had a very wet and cold spring/summer in Michiganbut this does not seem right to me.  Myhusband was putting in a fence post and notice that the water is just 3 ft.down this year. Note: we have had spring serious flooding the past four springswith so much water that the county had to extend the county drain and addedditches, culverts and tubes under our driveway to draw water away from our homewhich was surrounded by water for months at a time.
Could a hose be plugged? Or perhaps I don’t have the a/c setcorrectly? I have it set to come in at72 degrees due to the amount of moisture in that building. 
Any suggestions would be appreciated. I’m about ready tocall the heating and cooling contractor for a service but if I could avoid the additionalexpense as a retirees on a fixed income that would make me happy. 
Thank you.

Woodbridge Environmental Tiptophouse.com · Answer

How big is the AC system. Also if your home is leaking air, because of a attic power fan, poor air sealing in attic that will add to the humidity as it pulls the outdoor air into the house. 
Where is the AC system located? Attic? or is it sitting on the cement floor? Is the air blowing up and along the ceiling area or attic with ducts? Or is it blowing down into the floor where ducts might be located?

Over sized AC systems are one of the leading reasons why homes are to humid. They pull the temps down fast, but do so quickly, not allowing the system to run long enough to remove moisture.

If the return ducts are in the attic, or the system for that matter, Outside air can influence the conditioned air in the home. Outside air from within the attic space can be pulled into the system adding moisture that needs to be removed only adding to the load introduced to the system. So if any ducts are located in the attic, be sure that they are sealed using duct sealing mastic, not tape and properly insulated to remove any additional load on the system.

If the AC system is properly sized, No more then two tons or 24,000 btu's at most and the air ducts are sealed. Then the issue can be excessive air leaks into the building. Be sure that any attic fan is off, as most pull air into the living area which can contain moisture that the system needs to deal with, and check in the inground ducts to see that they are not filled with water.

a/c system not blowing cool air, just air is blowing

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