I need to temporarily move the outdoor unit to one side to access the wall behind it. Is it possible to do this with basic tools? I just need to disconnect the copper pipes as there's enough slack in the power supply so I can keep the wires connected.
Absolutely not. These lines contain a refrigerant/lubricant mix under pressure. The lines also must have no dirt, water or air in them, i.e. they have to be bled, evacuated to fairly high vacuum and refilled that way. You'd need to invest in a lot of tools specific to refrigeration to do this, e.g. a pump.
You may be able to move the condenser without disconnecting the lines, but if you're unsure it's probably not best to try.
I was in a similar situation where I needed to replace the siding on that wall of the house, but the AC condenser was only about 6 inches away from the wall. I was able to move the condenser about 2' away from the wall by simultaneously moving it away from the wall and lifting it up off the ground. While holding it in the air, I slid a temporary platform I constructed underneath the unit. I managed to do this all on my own with a 3 ton unit, but it was difficult. Two to three people would certainly have be preferable.
I think the determining factor if you can do this is how much "slack" you have in your lines. In my case, the lines ran up into the soffit, so I had about 8' that I could work with.
If you're very careful with it you can spin it 90 degrees making sure that the refrigerant lines are your axis and they don't move very much but the whole other end of the unit will be out of your way. I'm a professional HVAC tech and I have successfully done this. Just keep in mind if you cause too much torque and flex on those Flare nut connections they will leak. So I recommend if you're going to do it you have one person holding those line still while the other person spins the other end of the unit 90 degrees
But as always the best answer is call a professional
Knowingly releasing refrigerants into the atmosphere is illegal and could subject you to significant fines. Moving the unit with the knowledge that you are likely to crack the lines may be considered "knowingly". Please have a licensed service person remove the lines and purge the system in a legal and safe manner, it will save you money in the long run.
I just need to disconnect the copper pipes
The disconnecting part is easy but take heed regarding the concerns expressed in other answers that this is done correctly and legally.
You need an adjustable wrench and a set of hex wrenches.
- remove the valve caps. These are the two large brass caps facing you in the picture (NOT the small caps on the left). you will see a hex-head valve under each one.
- Close the valve on the small (upper) line.
- Turn the unit on, COLD cycle, and listen carefully to the outer unit. After a minute or two the motor sound will change slightly - this is when all the refrigerant has been pulled into the power unit and the air handler + pipes are empty (of anything - they will be near-vacuum).
- Close the valve on the lower (large) line.
- Turn the unit off and unplug it.
- Crack open the nut on the large line. You should hear gas hissing - that is air going IN to the system and it will stop soon. If anything comes OUT, close the nut immediately and repeat the above. For reference, the pipes carry semi-liquid refrigerant at about 100+ PSI. It will be very obvious if they are pressurized or vacuum.
- Once the hissing stops you can disconnect both lines. Put the valve caps back on and cover both the exposed valve ends and the pipes with electrical tape. You can now move the unit anywhere you want.
CONNECTING it back up afterward is in the call-a-pro category. You need about $500 in specialized tools and a bit of practice, so it isn't worth the expense.