Is it difficult to replace an Air Conditioning Unit for my home?

Question

Am trying to save some money by replacing my 1989 Package Air Conditioning Unit with a new one by purchasing a new one and replacing it myself. It's a heat/air unit and know weight is a factor but don't know about the electrical side of it (yes, it's electric). All ductwork is ok, might change the thermostat. Thanks if anyone knows the difficulty of switching out a unit. Thanks

Answer 1

First of all, the amount of freon that comes pre-charged in the condensing unit is only sufficient for a certain length of copper pipe and takes only a certain amount of rise into consideration. There is no way anyone can tell you the precharge is satisfactory without knowing how long your copper lines are, how much they rise to your air handler or how many turns the lines make before they get there. I've installed hundreds of units and the odds are that the precharge is not going to be sufficient.

Additionally, 4 hours of vac time means absolutely nothing. You have to pull down to -30 on the compound gage and it has to stay there on its own while the vac pump is off. Not only does this ensure all moisture is removed from the system, but it also ensures moisture can't get back in.

My advice is that if you really want to save money, have someone who knows what they're doing do it. And not just anyone. Talk to their customers first.

Although the work itself isn't all that complicated, the knowledge of doing it right is complex enough that even people with a year or two of experience still do it wrong. It is possible to damage the compressor because of install mistakes. The odds are also very good that your system will be much less efficient, wasting energy and costing you heaps of money in the longhaul. You will void warrenties and you may have a hard time finding a service technician that will even touch it at that point, at least one that will charge anything close to a reasonable price.

You may end up spending $1000+ on top of your original investment simply because you didn't know one of the hundred, stupid little things an experienced tech knows when doing an install like this.

Answer 2

Easy to do and a huge savings.
First the AC/Heat pump compressor unit is FULLY CHARGED WITH FREON so dont go buying any of that stuff. Here is what to buy exactly.
1. proper size heat pump compressor unit in tons and Voltage. (Heat pump is an AC with a reversing valve built into it.)

2. A brand new Line Set of sufficient length.

3. A brand new "A" coil with the proper size orfice. An orfice size will be give in the literature of the compressor unit.

Be sure to use the proper size Orfice in the A coil. That size is given in the compressor installation manual which comes with every unit. Install that before going to brazing in the line set. Its located in the A coil itself on small line (high side)

A map gas torch with map gas + oxygen bottle. to braze the line to the compressor and to the A coil. Use a SELF FLUXING ROD called SILFOSS OR SILPHOS (silver + phosporous rod) No flux required and you cannot mess up. Just heat that slip connection red hot and put the self fluxing rod to it. IT NEVER LEAKS. Ive done at least 50 of these in my apt complex for maintenance and NOT A SINGLE LEAK. So dont go using no propane and solder or those quick disconnects. Welding supply has Silfos.

You are nearly done except for pulling a vacuum. Rent a 2 stage vacuum pump. Hook it onto the the connection at the compressor specific for that to pull a Vacuum on the "A" coil and the line set. Leave that vacuum pump on there pulling out moisture for at least 4 hours. That will dry out the line and A coil. Remember, that compressor unit is fully charged with freon so no vacuum is required on it.



Now shut off the pump and leave a vacuum on the line set and A coil dont release the vacuum. Then open slowly the valve on the compressor unit to release the precharge of Freon to the whole system. There are 4 valves total. 2 on the LOW side and 2 on the HIGH side or exit from the A coil side. Open all 4.

You are DONE The precharge of freon in the unit is preset for a normal 25 foot lineset and no additional charge is required. You can now run the wiring for the unit. There is a schematic on the backside of the furnace door and the backside of the electrical access panel to the compressor unit. No other instructions are needed. It will show the 220, 110 and small wire 24 volt thermostat connections right on there so you can procede with full confidence.

You can buy surplus AC equipment at www.usamfg.net for pennies on the dollar. I have delt with them for years. Brand new slightly damaged equipt. To get the good price establish an account with them thru your business address.

Answer 3

It's not even necessary to change out the thermostat. Wiring is according to an industry standard, but make sure you shut off the power before you begin (I assume it 220 volt). The wiring should be the same as the old unit. Black is hot wire, white neutral, and green is ground.
The biggest concern youhave should be in making sure the unit sits level, drains properly, etc.
I think you can handle it! Good luck

Answer 4

I would listen to Maru and hire someone else. In order for an A/C to run at it's rated SEER value it must be dialed in exactly using very expensive and accurate equipment. Self installation is not recommended. If you live in the south this will end up saving you money in the long run if you get a good HVAC man.

Answer 5

If its an exact replacement.its approx. 2 to 4hr job.We love these because it highly profitable for the installation tech.Disconnect power., low voltage. duct work. Slide old unit out of the way. slide new unit into place.Connect duct work.power, low voltage.Read all instructions with unit and then enjoy a job well done. GOOD LUCK!

Answer 6

Not enough info. I recently wired a 20 unit condo/office complex and had four different amperage to deal with. You need to get a spec sheet on unit and compare it to existing wiring. If it does not match it needs to be changed not rigged.
Have a pro look at it if you are not sure.