A/C not cooling

[Jonathan329]

Hi,

My problem is with our air-conditioner.  We have had it serviced a couple of times now, and are still having problems with it.

In my opinion, it doesn't seem to be blowing enough air.  Cool air does come from the vents, but not really with the amount of force that I would expect it to.  The first time we had it serviced, the service guy said that the outside unit had got sort of crudded up from mowing the grass, etc., and that he cleaned it, etc.  He didn't charge us for the service charge, but did add a bit of freon, and did charge us for that.

I don't know if he didn't close it up properly or what, but shortly thereafter our inside unit was covered in frost and not blowing.  We got a different guy to come, and we were low on freon.  He added more, and it worked great for a while. 

Now, it just doesn't seem to be getting enough air.  We have changed the air filter (and change it regularly).  Even if we pull out the filter it doesn't improve airflow. 

Suggestions?

Jonathan

[Pegi]

For it to frost up has to be low on freon...also has to have a leak to be low on freon...what is the Brand, Model number, Serial number and age of this unit..ice clogging the evaperator will cause low or no air flow....the motor not running fast enough will cause this, could be a bad capacitor or bad motor...suspect capacitor first if the evaperator is not again clogged with ice....could have a broken evaperator blower also...

[Jonathan329]

Oh, I should have specified--

There is no frost now.  The first guy said it was barely low, he put in just a little bit.  I suspect he left something open or something like that, as it *was* low for the 2nd guy.

Now, I don't have frost at all.  Just not enough air. 

Jonathan

[Pegi]

Still do not see a brand, model and serial number and age of the unit.

[Jonathan329]

Indeed. 

You want the brand of the inside part, or the outside part? 

I.e. Will I find that one the box thing outside, or in the closet inside?  Sorry, I know basically nothing about HVAC. 

Jonathan

[Pegi]

Ok, I thought it was a wondow unit....will need for others to help you with central a/c questions...

[Jonathan329]

Inside unit is a Tempstar, outside is a Trane (I think...dog finally hushed, I check for certain later).

jonathan

[hvacdrd]

Need some specific information to help you along. Your turn to work...

1 - General location where you live

2 - Size of home in sq. ft.

3 - Model number of outdoor unit

4 - Room temperature

5 - Outdoor air temperature

6 - Air supply temperature at supply air register as close to the inside unit as possible

7 - If possible temperature insulated line at outdoor unit

8 - Temperature of air coming out of outdoor unit

Note: all measurements should be taken after system has been running 10 minutes...now get after it and we will see what we can figure out

[Jonathan329]

Having a bit of cold snap, so no air conditioner running at all at the moment.  Thus, no temperatures.  I'll have the model number later today.

Cooling aside, there is no heat blowing at all.  The furnace kicks on (we have gas), but nothing comes out of the vent.  (Gets warm in the closet, but doesn't go anywhere).

If I turn the house fan on (with no heat), I get the same sort of weak airflow as from the air conditioning. 

My father in law thinks the compressor has gone out...that sound about right to you all?

Also, after we had it serviced the second time, there was a LOT of air flow coming through the vented door where the inside unit is (worked quite well while it worked), vents worked fine, etc.  Don't feel any of that now.  Also, shortly before it stopped working, the air conditioning was making a small pinging sound.  Much like what it sounds like when it rains if you have a metal chimney, or a very light rain on a metal roof.  Just a slight little pinging sound occasionally.

Shed any light on the subject?

J

[Guest ahammer48]

Hello

Just want to make sure I have this straight. This is a split (furnace and fan section in the house / compressor and condenser outside) central A/C unit ???

If this is true then the A/C and heat use the same fan  to blow air around your house, and right now U believe that the amount of air Ur getting is not enough??

Some things to check:

Is your filter clean? Filter is located either in the furnace section or possibly in the main return air grill to the furnace section. I have seen jobs where a return air filter grill was installed but the contractor didn't relize there was also a filter in the unit so the home owner is changing the filter in the grill but the one in the unit is clogged up with dirt. U only need 1 filter. Make sure its clean.

Jonathan329 wrote

Also, after we had it serviced the second time, there was a LOT of air flow coming through the vented door where the inside unit is (worked quite well while it worked), vents worked fine, etc

From UR post I'm assuming Ur furnace/fan section is in a closet in the house and I'm concerned that alot of air was coming out of the door slots. Thats an indication that a panel was left off Ur unit or theres a big hole in Ur ductwork. On Ur thermostat you should C a switch/button marked fan on/auto. Put the fan to on and open up the closet door to the furance. Do U feel alot of air movement? Find out where that air is coming from and get back to us.

Unplug the furnace and remove the panel that exposes the fan motor and blower assembly. Older furnaces had a fan belt between the mtr and fan assembly. Do U and is it tight? If no belt take a flashlight and look at the fan blades of the blower assembly. The blower assembly looks like a big round wheel with many blades on it. In the trade we call it a squirrel cage(looks like the wheel a hamster runs in). Use a finger and slide it down some of the blades. Are the blades full of alot of caked on dirt? The blades are curved. If they get full of dirt that makes them flat and they lose the ability to throw air. If yes the the blower assembly should be removed from the unit and cleaned by rinsing with a hose.

NOTE:yikes::poison: If U have a direct drive fan assembly( no fan belt) and U clean it Ur self do not get any water in the motor. The motor should be removed 1st.

If all this looks ok then put the panels back on and plug the furnace back in. Start the unit in heat mode and go back to the unit. When U get to it the burners should be lit off(the gas should be on) after a minute the fan should start and stay on . Does it?

Get back to us.

Hope this helps:)

[applianceman18007260692]

from what you said about the noise in the blower you might have a blower wheel sepperating have you checked that?

 

[brandonh]

Hi jonathan, It sounds like you have an airflow problem to me.  This will definitely cause your A/C to freeze or frost.  This could be the result of a few different problems ( dirty evaporator coil, clogged blades on the squirrel cage, dirty filters, or even something partially blocking the return grille, like maybe a peice of furniture).  You can check the temp difference of air entering the system at the return grille versus the temp of air coming out of the supply grille closest to the furnace.  In cooling mode, it is normal to have a temp difference of 16 to 20 degrees depending on humidity, if the difference is more than 20 degrees then you can be almost certain that you have low airflow. 

 

Example:  Air temp entering return=  75 degrees should have a supply temp of between                 59 to 55 degrees, if it is colder have someone come out and check evaporator

                for cleanliness. 

Also make sure that there are no cracks or openings in the joints where the sheetmetal plenum meets the coil that would cause you to lose air directly into the ac closet.