Home AC Freon (1 Viewer)

[Chris Huber]

Hey guys, I was wondering about home AC. Some poeple have told me that ACs are a closed system, and you shouldn't need a freon re-charge. If you do, then you have leak. other have said that you can actually use up the gas particales, making them less effective at cooling.

Lately, with this hot weather, my trane XE1000 just doesn't seem to be putting out the coldest air I've felt, and it takes forever to cool off the house in this weather.

What have you guys heard about home AC re-charging? Is it needed ever 5 years or something?

 

[Dheiner]

All systems leak. It's a question of how much. If your AC unit has not been seviced in five years, I'd bet that you need a charge. It's a good idea to get your furnace and AC serviced once a year, and included in that should be a pressure check. There are limits as to how much refrigerant can be charged into a system. I would get an HVAC guy to take a look at it if I were you.

 

[ChristopherDAC]

You need to have your AC system looked at annually. Unless there is something seriously wrong, you shouldn't be losing refrigerant, because its molecular weight is much greater than that of air and the system is tightly sealed. You may well be losing cooling power from another cause.

The refrigerant cannot "wear out", because its properties are physical ; it would be like wiring wearing out from conducting electricity. On the other hand, the motor can wear out, the coils can get clogged up, all manner of things can happen to reduce the effectiveness.

 

[Dheiner]

Umm, molecular weight??? Do you mean molecule size???
But, nevermind, neither really matters in this case. You lose refrigerant, over time, due to it being at (much, in some spots in the cycle) higher pressure than atmospheric.

 

[Clinton McClure]

It sounds silly but make sure you also change your air filter at the return air vent when it gets dirty. Depending on local weather conditions, this is anywhere between 30 and 90 days. I second the annual service. For the time being, you can try shutting off the power to the AC unit at the breaker (this is VERY important), removing the fan cover and using a water hose with a pressure nozzle to blow out the coil. Make sure you blow it out from the inside, then clean off the outside, then work on the inside again. Keep alternating until there is no more debris leaking out of the unit vents. Over time, the coil gets clogged with dirt, grass clippings and other debris and can literally smother the AC unit. Think of it as your car's radiator: If it can't breathe, it works a lot harder to cool and can cause problems ranging from taking a long time to cool your house to burning up the compressor altogether. I actually did this yesterday with my AC unit along with my parents' AC unit. Both were considerably dirty and took about 15 minutes each to clean.

Another possibility is your thermostat going out, but wise money would be on having a certified HVAC technician giving your unit a thorough exam. While they're cleaning and checking, they should also clean your furnace vents. Soot and corrosion builds up on them and causes the same problems a dirty coil does for the AC.

 

[ChristopherDAC]

No, molecular weight. The higher the molecular weight, the slower the diffusion of the species. Now, helium has a higher diffusion rate than hydrogen despite its higher molecular weight, because it is a monatomic gas and its atoms are infinitesimally small (even for atoms), but that is a special case.

Helium can escape through brazed joints and the walls of copper tubing, but you need an actual leak for any significant quantity of Freon to escape in anything less than centuries, high pressure or no.

 

[JoeyR]

check my posts here, I'm a commercial HVAC technician

YOU DO NOT HAVE TO HAVE YOUR FREON ANNUALLY REFILLED OR CHANGED OUT, sorry about the caps but thats how mad this makes me. It has nothing to do with molecular weight, density, etc. I have seen a/c's run for 10 years and never need freon. Usually if you have your system maintained you will lose some freon everytime the technician hooks up his gauges. By federal law a technician must use "low loss" fittings to assure that only a small amount is loss. Anyway the freon loss is minimal and you only lose freon when you have a leak.

Now if you arent having your unit serviced that could be part of the problem dirty evaporator(inside) blower or condenser(outside). Your outside unit will get dirty alot faster than inside as long as you use a filter and change regularly. Cheap Wal-Mart filters(2 weeks to a month), Pleated filters(1 to 3 months), any of these special super duty metal 7 ply filters people like to sale will KILL your compressor. Depending on who installed your system and how much they care about the job you do even pleated filters will put a strain on most residential units. I would get a preventive maintenance pulled on my unit but beware you have waited to the heat of the summer, turnaround time may be slow and the price will probably be high.

Also units are made to run up to 95 degrees outside air TOPS. For every one degree above 95 it is outside, your unit loses a certain percentage of capacity so even a perfectly designed and working system could seem problematic on really hot days.

Change your filter and make sure someone comes to do a maintenance on your unit. Air conditioning and heat is usually the most forgotten or nonmaintained item unfortunately when cost wise over time it could cost you more than most breakdowns on other things.

 

[BrianW]

Joey, that's just crazy talk. Next, I suppose you'd also tell me that I don't have to go to the Chevy dealership to have the air in my tires changed out twice a month.


Seriously, Joey, thanks for the informative post.

 

[JoeyR]

np if anyone needs any help hit me up

 

[Chris Huber]

Thanks Joey!

It's been 100 degrees here during the day, so thats prolly why I am seeing a strain. I have the AC setup to turn off at 8:00 and come back on at 4:00. It takes a long time for the unit to cool the house back down. Today I just sprayed out the coils/radiator part around the fan, not much of an improvment...

 

[mylan]

What about servicing Puron units? We opted for Puron when we built in 2004, at least for the upstairs, and we are very pleased overall. We keep the temp at 77 or 78 during the summer, any lower and it freezes us out/

 

[JoeyR]

Chris didnt notice this in your original post, are you cutting the unit completely off or are you setting the temp back and to what

 

[Mark Paquette]

Joey,

Is it normal for an AC unit to pretty much run all day when it's over 100 outside? I live in the south east, new house and last week the highs ranged from 102-108. On those 100+ degree days my AC runs continuously all day. It was able to hold the inside temp at 75-76 and started cycling after about 9:00 PM in the evening.

 

[Mort Corey]

Just an aside, but if your AC unit it only five years old then it likely uses one of the newer refridgerants vs "freon". If it's old enough and does use freon (and you have a leak) be prepared for an EXPENSIVE repair. "Freon" is really expensive in the US since it was taken off the market.

Mort

 

[aaron campbell]

"FREON" which is R-22 for central air is still in production and will be until 2020. In 2010 no new R-22 equipment is allowed to be produced. R-22 will be available for years to come, but will be more expensive in future years. 30 lbs. of R-22 is currently $119.00($4.00 a pound)

 

[aaron campbell]

Joey,

Is it normal for an AC unit to pretty much run all day when it's over 100 outside? I live in the south east, new house and last week the highs ranged from 102-108. On those 100+ degree days my AC runs continuously all day. It was able to hold the inside temp at 75-76 and started cycling after about 9:00 PM in the evening.[/QUOTE

Mark, very normal. If you have 100+ outdoor temps, with 75-76 indoor, I would say you have an optimal system.

 

[Mort Corey]

I guess "freon" was being a a little generic in terms...R-12 (I think that's the number) was used in older AC units up until the ?mid 90s? and, though still available somewhat, it's really expensive. My AC guy was saying that it has to be recaptured vs exhausting it into the air.....should you be replacing a unit.

Mort

 

[aaron campbell]

R-12 was used in automobile air conditioning, but mostly refrigeration
R-22 air conditioning (still in use)
R-134a replacement for R-12
R-410A (Puron) replacement for R-22

As I said before, R-22 is still cheap at $4.00 a pound
R-12 on the other hand is $40.00+ a pound

 

[JoeyR]

What Aaron said is right on

Units are designed to maintain 75 inside on a 95 degree outside day, so if you are seeing + 95 you can plan on your unit running all day