Before I start nosing around what kind of information do you need from me?

I'm thinking it will be:
Size of unit
Sq. ft cooling
Temp coming out of vents
# of returns and vents
Located in South Dakota - yes it gets to 100* here!!!

House:
Ranch, Atrex construction and attic properly insulated, roughly 4,500 sf including finished lower level. So approximately 2,500 sf on main floor. Basic problem seems to be airflow on main floor at one end of the house that has more windows...so last year I split a double wide return that was buried under a desk area that was choked way down with computers, chairs and a waste basket. I followed the space between studs to above the cabinets and opened it up way above clutter and closed down that stud space below the desk....that helped lower the temps in that room by about a degree. This year I've placed a tower fan blowing air from a return that's placed in a corner of the room and there is a noticeable improvement.

I finally discovered that I needed to keep the lower level (finished basement) unit a lot cooler or the hot air from there comes upstairs and adds to the problem.

I tested the air coming out of the ducts accidentally one day and it was easily 10 degrees cooler than the air in the room. (I was cooling my outside remote thermometer unit on a register because it was registering over 100 where I had moved it)

The outside unit coils are clean. The filters are only a few weeks old. Part of me wonders if the coils inside attached to the furnace are dirty...but I have no idea how to get to them.

The blower has been checked and is set to high while running AC.

Now I'll shut up and let you ask me questions.

Pam

 

I haven't had it serviced this year - forgot to add. Also asked last service about the size of the unit and how much it runs - was told it was at its max but should be fine....so I don't allow the inside temp to rise at night when we don't need it running - or it never cools down the next day. (as in the winter when we allow furnace to rest and house to cool....)

Pam

 

Pam, have you adjusted the dampers in the ducts to send more air to the hot end of the house? I have a 1400 sq ft ranch, and my furnace is in the basement at one end of the house. I have the dampers for the room at the other end of the house fully open, while I have the dampers progressively closed down for the rooms moving towards the end of the house that the furnace is in. Also, is the main trunk that feeds the rooms insulated to minimize the heating/cooling loss of the air going to the rooms?

 

To the best of my ability I've done this...unfortunately with a finished basement I have limited access to any dampers at all....I just now checked and there are no dampers. The huge rectangular supply goes straight up into the floor (where I can't see) and another same size rectangular piece comes off that to a 90* curve to to side of the house that has all the windows....

 

Also - I have a good sized ceiling fan in this larger area running at top speed - but in upward flow to send air movement to the entire area. That helps a lot. What usually happens is the thermometer in this area will read about 3-4 degrees highers than the ac thermostat located at the other end of the house.

And oddly enough - the furnace is CLOSER to the end of the house that's hot!

 

Unfortunately, with no dampers, you have no easy way to adjust the airflow to get more to the hot end of the house. I'm not an A/C pro, just an educated homeowner. Perhaps the pros have some ideas for controlling the airflow.

 

Pam, if you could post some pics of the air handler we might be able to help.

 

Now that I have done this I see how it's working. The 90* curve is the main trunk and then it breaks off from there. I need to move some ceiling tiles but it looks like I only have the soft 8" (guessing) diameter ducts coming off the main trunk....the first photo shows it coming off the main trunk and going into the ceiling space. I have old tiles in this room that need to be removed anyway - so I guess it's time to do that so I can see what's going on in there....

Pam

 

Did you measure the air temperature in Celsius or Fahrenheit?

If in F, 10 degrees lower than room temp is not good.

Check the supply and return temps at the furnace, going into the furnace and downstream of the indoor coil. check in two locations for supply in case one is not accurate.

At normal humidity levels, it should be 16 to 20+.

What size is the system? if you can't tell, post the model number of the outdoor unit and full model of furnace.

I would imagine 3 to 4 tons.

 

I will check the temps because that was in F.....but here is the outside unit.

Pam

 

Make sure the damper is closed on the humidifier. 3 Tons built in 1999.

 

Yes damper is closed. THAT one I can visually see.....

When I was outside looking at unit I decided to do a full hosing off of the fins...my fan/top didn't come all the way off very easily, but I was able to prop it enough to hose from the inside out first and then rinse anything else that was still clinging to the fins outside.....

Pam