Are there any A/C guys here?

[Yossarian]

My A/C in my home seems to be struggling a bit this summer. Mind you the house is only about 2.5 years old or so. We keep the house pretty cool at about 70-71, but lately we're getting some upper 90's outside and the house heats up to about 73 during the day, regardless of if the thermostat is set to 70. The A/C seemed to stay right on point last year. I change my filter regularly, and spray out the outside unit to clear grass and dirt, but that's the only maintenance I've done. Could it be a little low on Freon?

[Brownpatch]

I'm not a licensed HVAC guy but I did stay at a Holiday Inn Express last night. Seriously though, it possible it could be low on freon as was our house when it was a couple years old the company we hired for the tune up said when they install the new units sometimes they don't fill them properly so they end up settling and a little low. Also the coil could be dirty and unless you use the foaming coil cleaner it's difficult to get it clean. I have access to some through work and clean mine twice a year. It's always mind blowing how dirty it is. I'd recommend spending the $99 service charge most places have for a "tune up" which they should clean the coil and put a set of gauges on to verify proper pressures. If they want to add freon, ask how much per pound and make sure it seems reasonable to you.


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[KenFen]

I had this issue and while freon was fine, but as Brown stated, the condensor/coils were dirty. I would get a commercial grade cleaner and try that. Many HVAC companies end of overfilling freon levels just to make the customer happy and that is just as bad as being low.

[BoatDrinksQ5]

Most likely if your system/house is 2.5yrs old... coils indoor/outdoor couldn't be that dirty. However did you have this problem the last two summers?

Is there any ice build up on the furnace/AHU visible? Frost on the lines right near coil inside?

Double check that filter... also turn off system and let it possibly thaw (indoor coil could have frozen solid...). Check dampers and vents to ensure you system is having enough flow.

How many BTU's or Tons is your AC unit outside (usually a sticker in back will tell you)....how many square feet is house?

Sounds like you might need to give the HVAC contractor who did the install over to take a look it. Could be under manf warranty still if something is failed.

[LoneRanger]

I know quite a bit about HVAC, but I'm no licensed professional. The only reason there would be a loss a refrigerant, is if there is a leak. You need to call a qualified and licensed technician. There are many old timers still in the game. You can't teach an old dog new tricks. Freon is a trademarked brand name. Most likely your systen is charged with R-410A. Either way, refrigerant will need to be evacuated and a specific amount charged to the system by weight. Make sure your technician uses a scale to weigh in the refrigerant. He will also need a set of calibrated guages and temperature sensors. If there is a leak, it will need to be repaired first.

All that being said, how long has this been going on?

[dfw_pilot]

^^

[Yossarian]

I haven't had this problem the last couple of summers. No freezing on the outside line and the filter is clean. I'll go up in the attack and check out the inside lines. I may pay to have someone come out and give it a once over.

[Tony alony]

Yossarian, another issue that turns up regularly in newer homes, is the fresh air intake volume. In the almost totally sealed homes nowadays, fresh air intake is a major design feature. Perhaps you should have a qualified air conditioning technician take a look at the entire home comfort system( for lack of a better word), and have them check if the system is within tolerances. As you know, even the small amount of fresh air intake, with its associated humidity, has to be balanced with the overall performance of the system. There is much more to be considered as well. Have it checked by a professional, even though, in homes, static pressures is rarely a major consideration on performance, due to the smaller units, it can still make a big difference in comfort.

[Tony alony]

Yossarian, by the way, I've seen cinder block walls collapse from too much static pressure on room-to-room return air systems. So, hire a professional to check your system.
Good Luck!

[Overfloater]

If you have airflow coming from the vents then the coil cannot possibly be frozen over. I had a coil brick up once in Florida when my wife decided that the house needed to be 68 and the system ran all day without turning off.

Anyway, where are you located because that can be an important clue.

In the north, central a/c is generally sized to run at peak efficiency when outside temps are in the mid 80s. If temperatures go much above that, especially if it's humid, the systems can have a hard time cooling down the interior. This can be compounded by air leaks inside your house, and poor ducting installs.

I would start by checking your vent temps with a thermometer. Start at the plenum just after the coil and then check individual vents.

That will tell us if there is really a problem and point you in the right direction.

You should see a 15-20 degree drop in temp from ambient just after the coil. A smaller drop is normal at the registers.

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[Tony alony]

+1 Overfloater. Your advice to check temperatures at the vents would be beyond the scope of a normal homeowner. The key to success for any homeowner, regardless of their mechanical abilities, is knowing when to hire a qualified professional to help them learn. After learning what they are able to understand, there is still a limit to understanding all that is technical in any particular field. Some of the tips to learning can't be explained on site. Much of what you learned, was probably from formal training.
You can't teach the average homeowner everything you know; right?

[Overfloater]

I'm a technical crew chief with an airline by trade. I've had no formal training in HVAC. I have a background in mechanics. Everything I've learned, I've taught myself. HVAC systems are simple once you understand the basics.

But anyway, he sure can check the vents. Just stick a meat thermometer in there. Most people have those lying around the house.

There is a chance that his system is working perfectly fine since it's so new.

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[killerv]

I'd bet on a small leak somewhere on a system that new. It should still be under warranty. Buddy had a new air handler put in and they've already added 10 lbs of freon since the initial install. Took 3 trips before they found the leak.

[Tony alony]

Another thing to check is to take a look in the attic. Today's homes have tin foil ducts hung by plastic string straps. There may be a broken strap or sagging duct, or possibly a torn duct. Note: I'm using the term "duct" loosely, ha ha. In my own four year old home, I just pay the annual fee to have it serviced since the builders 10 year warrantee on mechanicals includes only the furnace. The air conditioning unit only has a 5year warrantee though. Go figure: in one of the hottest, and possibly one of the most humid climates. I jokingly asked the builder prior to move in, why isn't there a humidification unit for winter heating season. His reply : "this is Houston, not Chicago, you'll never need it". LOL

[Overfloater]

Problems with ducting can be detected be measuring register temps and comparing them to the plenum temp.

I wonder, has the original poster even been back to read this thread?

[ Post made via Android ]

[bassadict69]

I know house is only a couple years old, but how is your attic insulation? Did they properly insulate to begin with?

[Yossarian]

Our insulation is really good. I had a guy come out and we ended up being a few pounds low on freon. The rest of the system appeared to be in good shape. The tech didn't think that there was a leak. The only thing he could think of was a very slow leaks at the valves where freon is added. It's cooling well now, so we'll see.

[Overfloater]

2lbs is quite a lot. How many pounds does your system hold?

Sounds like you have a leak. Only time will tell how bad it is.

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[LoneRanger]

Yet another unqualified technician providing disservice to the customer and public.

[HanLawn]

Our insulation is really good. I had a guy come out and we ended up being a few pounds low on freon. The rest of the system appeared to be in good shape. The tech didn't think that there was a leak. The only thing he could think of was a very slow leaks at the valves where freon is added. It's cooling well now, so we'll see.

Find a better tech going forward......a "few pounds low" is quite a bit on any system,much more so on a 2 year old system.A true pro would have used a electronic leak detector and found the exact source of the leakage,then repaired the leak,before refilling the refrigerant.What you got was a "down and dirty" "gas and go"......the problem will continue,and you will pay over and over for future "gas and go" visits.If it turns out to be a leak at the evaporator or condenser,the time to find out is NOW,while it is still under manufacturers warranty,as either will be a large expense.