How do you add Freon to your central air conditioner unit?

Install your can to hose. The screw will turn into can-puncturing it and shutting it off. Now disconnect cover from low side. It will always have the large head of the two lines on your outside unit. Install your hose with ac off. Screw it in an turn on ac. Slowly unscrew the ac or stop leak can screw making sure it is upside down feeding the line as the ac is running.

If you are savy smart with understanding in mechanical things it will be a sinch for you.
First you must throw the breaker before you dissemble anything to find where you need to fill your unit. You may not need to dissemble anything in some cases. But you must be on the low side pressure line. The smaller high pressure side can go up to 500 pounds or more pressure. I know a person can be injuried easily. I know of a man here in our area who connected to a high side line and the freon can blew up and removed his nose. So like the man above said strict guide lines must be followed to keep you safe. The low side line is usually about 40 to 60 pounds. This line is used to add freon. You can't just use any freon. You must use the freon made for your unit and most central units are the same. But everything is always subject to change so some study on your part would be worth it for you. Ask around talk to people and get some advice.Someone who has been there can assist you very much. Normally the unit will be turned on running at full speed to fill the unit with freon. And when a certain amount is reach or a certain low side pressure that means add no more. To much pressure on the low side can cause trouble. For most people a qualified service man is far better. But for some it is a piece of cake.

It's not illegal unless you discharge Freon into the atmosphere. Please don't post information without true knowledge of a subject.

how to tell the difference between high side and low side is the diameter of the line high side is the small line low is the small line. u can buy a freon leck detector and it will find the lick. i dont know what the guy was talking about with the nitrogen. i use to install ac in vans. the unit will tell u the low and high side pressures. my home unit is 150 low 300 high. its on the tag. R22 freon will be used in ac for homes. R12 for autos. but 1 thing for sure is that u have a leck u will have to let all freon out. true u r not suppose to do this but if no 1 c u then who knows. but when u repair unit u will have to pull a vaccum to remove all mosture then u can put your freon in. make sure u have the line hooked to the low side. u can probley put a can r 2 in with out turning on unit. then turn on unit and finish filling to proper level r pressure.

Wrong hvac, residential a/c uses freon22, not r12,
and the right pressure at low side is 68.5 psi, this will give you 40 degrees in the evaporator of the unit.
Certainly you have to use special manifolds to check pressure, and special equipment to perform a leak solder, and, for that guy asking if he can solder a leak with the refrigerant pressure present, NEVER EVER ATTEMPT TO DO THAT IS VERY DANGEROUS INDEED, YOU HAVE TO RELIEVE ALL THE REFRIGERANT BEFORE YOU ATTEMPT TO MAKE ANY SOLDER IN THE SYSTEM, IN ADDITION, THE REFRIGERANT MIXED WITH OPEN FLAME PRODUCES TOXIC FUMES THAT CAN BE VERY DANGEROUS OR FATAL IF INHALATE IN MEDIUM CONCENTRATIONS.

first of all freon is a dupont product, what you're looking for less specifically is refrigerant. but you probably don't even need that. 99% of air conditioning problems are dirty coils. first try using a garden hose to spray out the aluminum condensing coil. if somone tells you that your air conditioner needs "topped off" you just got "ripped off" and system is over charged. that is a "hack" way of making you happy and making them lots of money. furthermore if your system is low on a charge and has been leaking, any tech who doesn't locate and repair the leak before charging it is in violation of several federal laws and international ordinances for knowingly releasing refrigerant into the atmosphere. and yes you must have a licence to work on air conditioning. yes it is a bad idea not to reclaim your refrigerant before silver soldering or brazing your line set for a leak. it creates an acid gas that will kill you. no you can't just vent it into the air. air conditioning is not a do-it- yourself project. so for everyone who says " my air conditioner is running but not cooling" take it out and spray it down, dry it out and re-install it. if it still doesn't work call a licensed tech and make him show you his licenses, before he touches it because these idiots most of the time do more damage than good to your system because you have no idea what he's doing.

Bullshit, all it takes is a set of special gauges, knowing where to connect them to the low pressure (=thick) pipe a can of freon and a precious EPA cert which can be (legally) had online for about $30 (after passing a test even a waitress can master) and a lot of common sense, caution and patience. I am so tired of `certified technicians' who could not even get their high-school diploma telling us we cannot do the work ourselves and then screwing us every time they have to do a little check! Charging $15 per # of R22, as well. Illegal my ass!

I'm a certified HVAC Technician. I have been to college and have 12 years of experience in the field, so I may be able to help you with your problem. The problem is, you have a leaking system which needs to be repaired. Recharging a leaking system is just plan stupid! It's going to leak back out! In order to repair the leak yourself, you going to need the right tools. First of all, the R12 needs to be recovered from the system using a EPA approved recovery unit "at about $600 to $800 for the unit" and stored in a recovery cylinder "at about $80 for the cylinder". Next you need to purchase a set of refrigerant gauges at a cost of around $65. After that, the system needs to be charged with nitrogen. A small 2000 pound cylinder of nitrogen is around $60. You must also purchase a set of nitrogen regulators at the cost of about $80. You will then need to purchase a sonic leak detector at the cost of about $125 for a cheap one, to around $250 for a good unit. I like the sonic leak detectors, so that's what I suggest you use. Pump the system up with about 200 pounds of nitrogen and use the leak detector to find the leak. This may take anywhere between 1 to 2 hours depending on the size and the location of the leak. Move slowly and check all your solder joints. Next, if you find the leak and the leak is in a location where it can be repaired, your going to need a set of acetylene torches. You can pick a good set up for about $225 to $350. Next you will need a piece of 15% Silver Solder at the cost of about $3 each. Next remove all the nitrogen from the system and repair the leak with your acetylene torches. Now that you have repaired your leak, your going to need to remove all the air from the system. Your going to have to purchase a vacuum pump. You can get a nice Robinair 5 CFM Vacuum Pump for about $270. Now I can go on and tell you how to pull a vacuum on the system and charging the system factory charge using a set of refrigerant charging scales "at about $165" but, it's a waste of my time and yours. You need to stop listening to all these idiot know it alls, that have no idea what their talking about, and get a PRO to fix it. If it can't be fixed, replace the unit. If you can't afford to fix it or replace it or your just way to cheap for ether, buy youself a nice new fan a Wal-Mart for 10 bucks!

It is illegal - on a Federal level - to attempt to do this yourself unless you happen to be an EPA certified technician. Hire a professional.

Well I am 74 and retired refrg. eng. I have gone through all the phases of refg.Yes I have a license.You must be careful and make surew the right refg. is used. Some jerks will put propane in it. Ask my brother who does auto ac. Any way some mfgs. have a "blend" in their ac's such as puron. You MUST check the name plate and make sure what the refg. is. For the fellow from NC who gave out a lot of misinfo on some home ac's there are no service valves to isolate the system. Do your self a favor and find a reputal heating and ac firm. You might want to check them out with the BBB Have a REAL pro come and check out your ac But you can make sure the inside and out side coils are clean and that the filter is clean and that the blower is up to speed. A lot of times if the unit is low on refrigerant the indoor coil may start to frost over. Check the obvious first. Then call a GOOD pro.

Although it is very dangerous to do this. I will tell you how to go about it.
You should have a set of gauges, called a manifold, there should be a red one and a blue gauge..
The red one is for the high side, the smallest of the freon lines and the blue one is for the low side, the larger of the tow lines going into your unit.
It is possible to connect the freon lines while the unit is running. Connect the red hose to the small freon line and if the ac is running this line should be hot or warm. Then connect the blue hose to the large freon line and it should have some sort of insulation on it and if you feel it, it will be cool if you have enough freon in the unit.
You read the gauges like this. With the ac unit running first look the high side(red gauge and hose) you should have a thermometer set where the outside air is being pulled through the unit by the condenser fan, the fan on top or somewhere in the unit that blows air across the coil. (radiator looking thing)
If the ouside air temperature is 100 degrees you add 32 to that which gives you 132. On the red gauge you will see small numbers below the outer numbers and these numbers are green for freon 22 and other colors for other freons and assuming that you have freon 22 in your ac unit these are the numbers you have to look at.
The outer gauge at an outdoor temp of 100 degrees should read around 296 0r 298 psig (pounds peer square inch)
The low side, the blue gauge, depending on the inside temp of your house should be around 60-65 psig if inside of the house isn't too much over 80 degrees. Any higher temp inside your house it will be higher than the 60-65 degrees.
If the readings don't match and you feel it needs freon NEVER charge the system through the high side (small tube) use the low side and don't turn the freon gas can upside down because you will be sending liquid freon into the compressor and that is called "Slugging" it. A no-no.
The blue gauge will also give you some information. Look at the outer gauge and if its near 65 degrees in your house, look at the smalll green numbers and you will see that the coil temperature is.
Hope this works for you. It is a very involved thing and you really should have an someone with some ac experience near by.

Good luck
Bart

Yes, you can connect the gauges to the unit when it is running. the thin copper line is your liquid line use the red hose. The Larger of the 2 is your suction use the blue hose. The yellow hose is only used when adding freon or when removing moisture and non-condensiables from the lines.
Be Sure you have the correct hoses and don't mix them up r-22 has different pressures and oil than 410-a.
You will need a temperature gauge that can be fastened around the suction (large copper) line.
for r-22 on the suction side of the gauge you will see (psi) and (r-22 in green) if you focus on the r-22 side you will see a temp. if you subtract the difference between the suction temperature and the temperature gauge on the suction side you should get 12 if it is correct. Inside if you take a delta t' the difference between the Return where the filter goes and the supply where the air is forced out of the vents should range from 17-21 21 is the best you will get.
delta t's will range if per say the door has been opened and closed very often cold air is leaving and hot air is coming in. If the outside of the unit is very dirty causing an air restriction of air flow across the condensor coil. If the filter is dirty restriction of airflow to the evaporator coil. So there are a few things you should check before you just start adding. I DON'T RECOMMEND WORKING ON YOUR EQUIPMENY UNLESS YOU ARE TRAINED. If you are not be vary careful there is alot of pressure, power and moving party that could easly cause harm. Tip ALWAYS keep a rag near you when puting on gauges if you SLIGHTLY crack open the other end of the line on the gauges when you tighten down on the shrader valve it wont spray so much. Becareful and don't release freon into the atmosphere!!

steps are these...get the hvac pressure gages from local store ~ $65 bucksget the freon from wherever you canclamp ampmeter on the compressor electrical supplyadd gas until you see the compressor reaches the full load amps listed on the unit name platehvac places pretty much all rip you offanymore you might as well just replace the units with a high enough SEER rating to get the tax credit

In order to purchase refrigerants commonly called freon a license is required. Home AC units use two types of "freon". R-22 which is what is in the older units and R410A which is the new refigerant that replaces R-22 which is now being phased out due to its effect on the enviroment. They both do the same job but are totally different. In a nut shell R410A is a much higher pressure "gas". You need different equipment to work on R410A then you need for R-22. So a licensed service tech now must have 2 of everything to work on residential AC's. Basically the manifold, recovery tank, revovery unit and refrigerant. So be for we all get bent out of shape on a service call pricing lets consider what your and my friends at the EPA have mandated.
In order to repair leaks you HAVE to remove the refrigerant first!!! Think about it. What do YOU think will happen when you start heating a soder joint that has pressure behind it ? Its going to blow all of your solder out of the joint. Ask any service tech as we all have tried it when we first started out in the business. It did not work for us and it won't work for you either!!! You may also want to consider that we call them solder joints but they are not made with plumbers solder they are made with as stated in an earlier response with silfos. You can not mix the two. In other words one will not stick to the other no matter how much heat you throw at it. In regards to leaks....Leaks happen and they are sometimes very hard to find. They are the curse of every tech. You can spend hours looking for them. I have 4 different leak detection sytems on my rig. They all cost big $ and they all find leaks but they also all have their strengths and weaknesses. But in order for a system to hold a charge you have to have a tight system...NO Leaks. So the question is how do you fill it ? On a residential AC you will have 2 schrader valves at the condensing unit. That will be the part that is sitting outside with the fan in it. The schrader on the smaller line is the high side access. Your red hose goes on that one. The schader on the larger line is the low side access. Your blue hose goes on that one. So now what do the numbers on the manifold tell You. Exactly nothing unless you understand that it takes alot of time and training to understand what is going on in a modern air conditioner. There are a lot of so called techs that do not understand what is going on. If you called someone out to repair your system and it is not working right. Call them back and insist that they do it right. It's tough out there but we want happy customers. Look at it this way...sometimes it might be better to have an idiot that knows a little bit about somthing working on your equipment as opposed to an idiot(that would be you) that knows nothing at all.

you can not add/service or purchase refrigerant for central air system unless you are epa certified. witch it is very evident you are not. To correctly charge a system with refrigerant requires a pipe clamp thermometer and stick thermometer, gauges, and psychrometer, you also need to know what type of metering device you have (txv or fixed meter a.k.a. orifice). as far as bottle position it depends on the refrigerant and your knowledge, 410a must be added as a liquid. r-22 can be added as a gas or liquid, but adding liquid can kill your compressor by slugging it, liquid dose not compress!!!!! and in some/most circumstance it is illegal to add refrigerant without a repair or the leak first, witch meaning you will also need torches, vacuum pump, recover machine and a recovery tank. have fun ; )

these steps are best preformed with equipment running and out door temps above 65 degrees
1. hook up your gauges
2. attach pipe clamp
3. get indoor wetbulb
4. get outdoor drybulb (temp)
5. reference factory chart, line up indoor wet bulb and outdoor dry bulb
6. add charge to match superheat or subcool reading deepening on type of metering device (txv= subcool, fixed meter a.k.a. orifice= superheat)


so in other words call a N.A.T.E and EPA certified service tech

Do you have to vacuum down a central ac unit when replacing it

Yes, you must clear refrigerant from the lines to repair a leak. What none here have mentioned including the "certified technician" is that the refrigerant can be pumped down into the outdoor unit and locked in there (atleast I know it can on R22 can't remember on R410 as I only ever worked on 1 of them). That makes your life a whole lot easier unless your leak is inside the outdoor unit as when you pump it down its still in the condensor coils and such outside. On another note stop calling it Freon. Your house does NOT use Freon. Freon is a Dupont trade name for R12. Oh, and auto ac's don't just leak unless they are the older R12 systems. EPA licensing is for the purchasing of refrigerant not working on ac units. In the state of NC for example I was able to work on ac units under the small business owners state license but not buy refrigerant myself cause I didn't have the EPA license. License or no it is always illegal to vent to the atmosphere

Another thing, I saw someone say he didn't know what the guy was talking about with the Nitrogen. When we checked for leaks we pumped the refrigerant down to the compressor and trapped it there. Then we pressurized the lines with Nitrogen and checked our leak that way. Nitrogen is an inert gas, it doesn't carry condensibles (moisture) and it can be vented back off into the atmosphere legally as our atmosphere is mostly Nitrogen anyway. with this method we didn't have to worry about the refrigerant after we found the leak and saved as much as possible.

FIRST FIND THE LEAK. THIS IS THE ONLY WAY TO START AS THESE UNITS ARE SEALED AND DO NO JUST LEAK AS AUTO AIR DOES. THE UNIT MAY NOT BR REPAIRABLE AND ADDING FREON MAY NOT HELP AND ANY ADDED TO A LEAKING SYSTEM IS LOST ANYWAY