How much Freon(R-410a)is needed for empty new window ac unit (11,600 Btu) in general?

It depends on the system capacity doing it by weight , and if going by pressures, what the abient temprature is.

There is no general answer... other than what the OEM specifies for the unit

The window unit is GE AJES12DCC and GE would not tell how much refrigerant for this unit. I will install this unit in Chicago city and about 89 F in summer temperature. Any help?

As far as the actual pressures... you will be comparing the exact ambient temp at the moment at the condenser to a chart that will show the pressure at that Temperature, and yes it is important to know within a degree or two.. You have to have a set of A/C manifold guages with the correct fittings on the hoses, and the dial with a scale for R-410, most have scales for 2 or 3 types.

I'd have to look and see if I can find a capacity for that unit (I haven't yet as of this answer), but you would need a refidgerant scale to do it that way. Do you have either of these? Overcharging a system can damage it ( more is most definitely NOT better when it comes to A/C systems), undercharging its not going to work well or at all depending on by how much.

I can't get the GE intallation manual to load from their site... from what I can tell this is an all-in-one through the wall unit, and those are typically shipped fully charged. Like Window units...

Does the Installation manual say otherwise?

Any way you can estimate how much R-410A (maximum) so that I can get enough quantity ready to work?

I have no way that I can guess as to how much, I am not familiar enough with those to even guess.

Maybe someone else readying this thread would know. SO have patience, you might get the answer from someone else.

As far as I can tell if it's a new unit... you won't need any. If it's a used unit... and it leaked out, you have a problem that needs addressed first.

Did your installation manual state it will need charged? Because I could not get it to load for some reason to see what it says..

Two part units are always shipped without a charge... but filled with Nitrogen... the amount needed will vary by installation due to the unknown volume of the lines. But a one piece unit would usually be charged at the factory... and should not need anything for many years.

I agree with smoothy on this. If its window (one piece unit), it would come precharged. Most window units don't even have ports to hook gauges to. Even if it's a split system, almost all split systems come with the condenser (outside unit) precharged, and the indoor unit filled with nitrogen or helium. In this case you hook the system up, vac the system, and then simply open the isolation valves at the condenser. If this is indeed a split system, and its new, there should at the very least be a precharge, or working charge rating on the lable of the outdoor unit. Usually this is given in OZ.

If for some odd reason the system is not precharged, you should by no means guess at the charge. I would suggest hiring a pro to charge the system.

And also, as smoothy said, if this is a used system, and for whatever reason the refrigerant leaked out, or was let out to take the system out, you will need to determine if there is a leak in the system.

Are you positive it doesn't have any refrigerant in it?