It depends on the efficiency and the Max amp draw to be safe (you could be lesser to a point depending on minimum ampacity) There should be a plaque that has a max over-current or max breaker size. some high seer a/c's might need a 20 amp breaker for a 4 ton some older units may be 50, you really need to check it with the plaque.
About a tenth of a ton.
A 20 amp breaker might actually be needed for the installation. It depends on the wattage and voltage of the window air conditioner.
The wire is sized to the maximum overcurrent protection device (Max circuit breaker) ampacity. This is listed on the nameplate of the outdoor condensing unit. Size the wire to match the breaker.
a 2p 20 amp should work fine for a single 220 air conditioner,
The breaker type be it a single pole or double pole will depend on what voltage the air conditioner operates on. Once the voltage is established, the sizing of the breaker depends on what the current draw of the air conditioner is.
Yes. You should use 8 AWG wire from breaker to AC unit.
is it plugged in? froze up maybe? change the filter, or flip the breaker
Have you checked the breaker outside by the unit
Look at the current rating on the AC unit. If under 16 Amps use a 20 A breaker and 12 AWG wire.
If the power requirement is 120 volts it will be connected to a single pole breaker rated at the amperage requirement of the air conditioner. If the voltage of the air conditioner is 240 volts, then a two pole breaker will be required.
It depends on the size and efficiency of the unit. Look on the service plate on the unit. It's a sticker the manufacturer puts on. It will have the model and serial number and a max fuse/breaker rating. This will tell you what breaker can be used with that specific unit.
To answer this question the voltage of the air conditioner unit must be stated.