< 1 2 3456789 > 1 posts, read 151,253 times Originally Posted by ByteRider I have been in the industry for more than 15 years on the Gulf coast and i totally disagree. Not just anyone can replace a compressor. First how do you know it's the compressor? Second, what caused the failure? Was it a burnout? Why would I need to know if it was a burnout? What must I do if it was a burnout? Not to mention the possibility of electrocuting yourself. Next you use 15% silver solder not 50%. What are the dangers of soldering? What happens with oil residue in the refrigerant lines? What happens when flame is introduced to freon and freon residue in the lines? Ever heard of phosgene gas? What about the Oxygen Depletion Potential of freon? What about how inhaling freon causes heart arrhythmia? What about refrigerant recovery and disposal? What about evacuating the system? A/C systems, are very susceptible to moisture and other non condensibles. How are you going to purchase replacement freon with no EPA certification?

What about the life threatening dangers of freon? How much freon do you add? You just can't go by the factory charge on the nameplate. You have to take into account many factors and then calculate your super heat and subcooling in order to achieve a proper charge. There are so many things to consider before trying to tackle something like this. If injury or death doesn't deter you, then the fact that you did it yourself will probably void any warranty that come with your $1000 compressor should. I can look up how to do an appendectomy online and get step by step instructions but I'm pretty sure most people would agree to just get someone who has been properly schooled and trained to do it. This is not like changing a fuse or the oil in your car. You could die or even possibly kill someone else many different ways if you don't know what you are doing and I would never recommend a compressor change out as a DIY project for a novice. 16,739 posts, read 46,615,361 times 1 posts, read 151,139 times

9,224 posts, read 34,826,474 times Originally Posted by archcolin By yesterday's standards, a 2ton unit would probably be OK. By today's standards there no telling without a physical inspection of the home. Calculating a house for A/C requires a Manual-J worksheet. There are a lot of factors that are used in the calculation- # of doors and windows. Wall construction and insulation. compass direction (solar gain), etc. Then there's the Manual-D for the duct system. and finish all your calculations with a Manual-S. Today, there is no reason to guesstimate. By doing a thorough calculation you will have a system that works at peak performance with minimal operating expense. 2,398 posts, read 4,448,953 times Actually a license is only required if your system uses R22 freon, which of course most old systems do. If you have or are replacing with system with a R410-A refrigerant, no license is required. So long as your not touching a R22 system, your fine.

If your replacing a R22 system with a R410-A system you need a licensed HVAC contractor to recover the R22 refrigerant from the old system before removing it. Originally Posted by ComfortZone1971 If you haven't mastered the mysteries of the circuit broker or equipment disconnect, you probably shouldn't be doing anything yourself. Pretty much anything you touch now a days voids the warranty. dual split system air conditioner priceI wouldn't mass with the R22, but I wouldn't let a little thing like voiding the warranty stop me from working on it.average cost 3 ton ac unit I know the EPA would love to talk to you!average cost 5 ton ac unit You are required to have an EPA Section 608 Type II or Universal certification license to handle R-410A but no license is legally necessary for purchase.

"to handle"- means working on systems that support R-410a refrigerant. Originally Posted by K'ledgeBldr I stand corrected, I assumed since no license is required to purchase it, no license is required to install it. 1 posts, read 147,284 times 1 posts, read 144,056 times DEaler not compling with warranty 342 posts, read 1,022,362 timesThe air conditioner compressor is the heart of your cooling system. It is the most commonly misdiagnosed component in the system. At least one third of the time that the unit is said to have a "bad compressor", the compressor is in fact not the problem. The typical air conditioning service call would cost over $100. We will show you how to correctly troubleshoot your unit and avoid unnecessary replacement. This procedure will help you to check out the typical single speed units.**HOT TIP** If the unit is no longer under warranty and the estimated cost of replacing the compressor is over half the price of a new unit, it would be a good idea to replace the system.

**NOTE** Before replacing the air conditioner compressor you should identify and correct the cause of the failure. An acid test should be performed in the case of an electrical failure. There are basically four types of compressors that are used in air conditioning systems. A rotary compressor is commonly used in window units and some central ac units. They have been around for many years and are inexpensive and durable. A reciprocating compressor is the most common in lower efficiency split air conditioners. They are relatively inexpensive but not as durable. A scroll compressor is the most common type in higher efficiency equipment. They are very durable and efficient but are typically more expensive. The latest innovation is variable speed compressors which are commonly referred to as inverter drives. These are in the top of the line high efficiency units but they are normally the most expensive. First, we will check to ensure that the compressor does not have an electrical problem.

You will need a basic multimeter to measure resistance. Shut off the power to the unit and verify with the meter that no power is present. Next, you need to remove the terminal cover. Check to make sure that the wires and the terminals are not damaged. The typical unit will have three terminals labeled C, R, and S. You should check for continuity (less than 30 ohms resistance) between C & R, C & S, and R & S. If the resistance is significantly higher, then check to see if the compressor is hot. If the unit is hot, the internal overload is open. You will need to wait until it cools off to continue troubleshooting.If the resistance reading is high and the unit is cool to the touch, the compressor motor is bad.Next, you should take resistance readings from each of the terminals to the body of the compressor. A low resistance reading, means the motor is grounded and the compressor will need replaced. You should also check the capacitors. If your tests do not indicate a bad compressor motor but the unit trips the breaker or fuse, the problem may be mechanical.

In some cases, as the unit gets older it may require a boost to get started. Special capacitors called hard start capacitors are made for these situations. They are a combination of a capacitor and a built in relay. They give the compressor extra starting torque and the relay disconnects the capacitor after the unit starts. They are very inexpensive and can often extend the life of the compressor for several years.If you install a hard start capacitor and the unit will still not start, you will need to proceed with air conditioner compressor replacement.In other cases, the air conditioner compressor may run but not provide cooling. This can happen when a failure allows liquid refrigerant instead of vapor at the compressor inlet. The result is usually broken valves in the compressor. In that case, the air conditioner compressor or the whole condensing unit will require replacement. The basic process of air conditioner compressor replacement begins with shutting off the power to the unit and recovering the refrigerant from the system.

This is required in the United States for compliance with EPA regulations. A recovery unit is connected to the system and the refrigerant is pumped into a storage cylinder. Mark the leads and disconnect them from the terminals.Then, the copper lines connected to the inlet and outlet of the old compressor are cut loose. The mounting bolts are removed from the base of the unit and it is removed.The new compressor is then mounted in the unit with the mounting bolts. The copper lines are then brazed to the inlet and outlet as dry nitrogen is purged through the system. A liquid line filter/drier should be installed anytime the refrigerant system is opened to the atmosphere. A suction line filter should be installed on the unit if acid was detected.After the system is sealed, it should be pressurized with dry nitrogen and checked for leaks. Then, a vacuum pump should be connected and the system should be evacuated. It is a good idea to leave the vacuum pump running for several hours.The electrical wires should be reconnected to the terminals.