How do you add Freon to your central air... (by 13 users)

How many degrees does it have to be outside to recharge an AC unit?

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.

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.

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.

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.

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.

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.

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

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

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.