Air Conditioning - 3 yr old A/C unit does not cool

Hi, I'm really glad I found this forum! I would appreciate any advice from anyone (I know nothing).

I have a 3 yr. old house w/ a 3 yr. old A/C Heat Pump unit to match. It is a split unit with half of it outside, and half in the attic upstairs. The heater works fine.

Last summer, I noticed the unit was having an awful lot of trouble keeping the house cool. It was blowing semi-cool air, but not able to keep the house below 85 degrees on a hot, sunny afternoon.

So a technician from the company that installed the unit came out to look at it. $50 later, he left telling me that the unit was working properly (temperature drop was what it was supposed to be). Well gee thanks, but that doesn't really help me keep my house cool. This happened to be in the morning when the unit was actually able to keep up.

Well come to ths year, the unit is not working at all. The fan kicks on and it blows out air, but the air is warm or even hot I might say.

I have scheduled an appointment for tomorrow afternoon for a technician to come look at it. But that is gonna cost me $95 the first hour, and $80 / hour after that. That seems expensvie.

Does anyone have any insight as to what the problem may be? I don't want to get screwed over again. I don't mind paying some money, as long as the unit gets fixed.

Thanks alot!

You ask a lot and not much info . INFO INFO helps us to help you. Just what do you have there? Inside fan runs. Outside fan run?? Compressor run outside? Is air filter clean? When unit is running is the big copper line cold and wet small copper line warm to hot outside at the unit??

Sorry about that, it just I don't know much about A/C units, and not sure what information to provide, so I will do the best I can.

The unit is a Rheem Classic heat pump. The inside fun runs yes. To my suprise, the outside fan is not running. It is making a humming noise and smells a little burnt. I'm afraid the fan is going to have to be replaced. I notice that there are three wires coming from the fan, black, brown and orange. The orange wire is not connected to anything (is this bad?).

I am an electrical engineer so if you need me to break out the multimeter, no problem! But when it comes to compressors, I have no idea how to tell if it is running. I just put in a clean air filter.

The unit has been off so i will turn it on, and check the copper lines. How long do I need to wait before I can tell?

Here are some pictures I took of the electrical box:

http://www.kwahn.com/FTP/public/IMG_4044.jpg
http://www.kwahn.com/FTP/public/IMG_4045.jpg

There seems to be a problem with the cylindrical piece at the top of the first picture, with the orange, purple, and brown wires (what is this called?). The plastic piece is cracked and I'm afraid, all the wires may not be making electrical contact.

Contactor..... It does not look to bad. Where is the crack?

The top of the capacitor is cracked off & the other leg of the fan is not connected to common on the cap. Is the compressor running(vibrating)? Disconnect power to the unit put the orange wire back on the common of the cap power the unit up if the fan runs I would amp out the fan motor (operating amps should be on the sticker on the motor) to make sure the windings aren't damaged if the motor check out I would replace just the capacitor.

So I take it that round cylindrical thing is the capacitor? Forgive my ignorance, but which pin on the cap is common? There is a brown, purple, and dark orange wire connected, is one of those common?

Once I get the orange wire connected I will turn on power, and see if the fan is running and go from there.

airman.1994, if you look in picture 4045, you can see that the gray plastic piece is cracked. It is also no longer sits as it should, so I'm wondering if there is electrical contacts underneath there that might be getting messed up.

Had a tech come and look at the unit this afternoon.

He replaced the run capacitor. The outside fan is now running, cool air is coming out the register. There has already been a 1 degree drop in temperature in about an hour.

I found out that the builder may have improperly installed too small of a unit. My house is 1500 sq. feet and I have a 26000 BTU unit. The tech said that is not efficient.

Also, he said I have a 1/4 in liquid line installed, when the 1300 sq ft house next door has a 3/8 in liquid line.

We walked down to the exact same model of house in the neighborhood. They had 31,000 BTU unit installed.

Looks like I will be calling the builder to find out what's up....

Does the unit cool well enough for you? Are your electric bills high? If it cools good enough for you & your bills aren't too high I would run it till it died. Than replace it with 3 ton unit (maybe a 3 ton air handler & a 2 1/2 ton condenser)& a new line set 3/8" & 3/4" refrigerant lines. That unit you have must whistle like crazy with only a 1/4" liquid line.

Mike, first of all, thank you for taking the time to help me. I really do appreciate it.

My electric bill at the most expensive in the winter is around $170, I do not think it gets more expensive than that during the summer, but I do not push the system very hard (thermostat set to 77).

But it still can't keep up on a hot day, so no, it doesn't cool good enough for me to be comfortable.

The contractor told me yesterday that even though it is able to keep up in the winter, it is not running efficiently because the emgergency heat is running more than it should be.

I am going to look into solutions that involve the builder covering the costs for the proper sized unit, installing attic fans, whatever it takes. I am the original owner of this house and they should've got it right 3 years ago.

Although admittedly, it shouldn't have taken me this long to figure out the problem.

Keith

3 years ago, Joe builder, who was the General Contractor for your subdivision sub contracted your a/c - heat to Joe HVAC contractor to put the system in.

This is usually "gravy work" for residential contractors. 1200 sqft house takes a 2 ton unit. They use the rule of thumb, which is 600 sqft per ton.

You have 1500 sqft, equals 30,000 Btu cooling. You have 26,0000. And, you walked down to an identical model home with a unit rated at 31,000 btu.

With the system you have (again, using rule of thumb) you are undersized for cooling and heating, heating is only ok because your thermostat starts electric heat to keep up with the demand for heating.

Now lets go to a smaller nutshell. You indicate, rightly so, that you intend to go back to the builder (General Contractor) to fix this situation.

Step one is to find a company (not the original) to come out and do a Manual J Load Calculation for the house to determine without a doubt what size syetem should be there in the first place. This will be an out of pocket expense for you, but you will have ammunition if you intend to fight the builder.

Now, Joe General contrator is probably going to tell you to pack sand and your off to court.

So, to summarize, your system is undersized. You can't really, I don't think, (lawyer stuff here) go back to the installer as he was subcontracted by the builder.

Get a load calc and go from there.

Chris

I called the general contractor, as you put it, this morning to get the ball rolling. Of course, they told me that the AC was no longer under warranty, but if I suspected they installed the wrong unit, that I should call the HVAC installer company.

Now these houses are cookie-cutter models so they have a pre-determined load calculations for each of the models. I called the installer company this morning and they told me my model was rated for a 2.5 ton unit, which matches the 31,000 BTU rating I've seen on two other houses now, of the same exact model in my same neighborhood.

They seemed willing to investigate this if for some reason they installed the smaller 2-ton unit, instead of the one that was documented. They were not exactly friendly about it, but they at least made it seems as if this is the case, there may be a chance to get the situation rectified.

BTW, you are correct, I work in electronics. The capacitors I deal with are very small, sometimes even surface-mount. They look nothing like the run-capacitor of an air condition, which to me looks like a cylindrical piece of plastic. Although now, I understand they serve the same purpose (to store charge).

As far as capacitors go yours store charge as ours do but the similarities sort of end there. We use start caps (which only stay in the circuit for a few seconds to give the motor a large kick in the butt to get it moving on start up due to high starting torque.

We use run caps to actually move the sine wave forward. This helps the motor run more efficiently and cooler. Without them we would probably all have 3 phase power at our houses.

Back to you, you never gave to model number of your unit only Rheem Classic.

In a perfect world, the installing company would find that the wrong unit was installed in your house and would replace it at minimal or no cost to you.

If you do have the wrong unit, someone else has one that may be too big. Or actually just right.

In cookie cutter houses the house is taken into account for unit size, but not real world conditions. Like orientation, trees and the like. It's all on the architects drawings not based on the lot it sits on.

Good luck, Let us know what happens.

Chris

The HVAC company came out and took a look at my outside unit and agreed that the specs for my house plan called for a larger AC unit than what was installed. They looked at the inside unit and said it was ok.

I asked about the 1/4" liquid line and he said it was acutally 5/16", which he said is ok.

They said it was their mistake, and that they would "make it right". They are going to install the correct 2.5 ton unit within the next few days free of charge!!!

I am very happy that they are doing this and without a big hassle. That is a good sign for the company that takes responsibility for its own mistakes.

I wanted to thank everyone here for all the helpful information. THANK YOU!