I have a Haier air conditioner model HWR10XC6. It's been in storage since last fall, and I put it in our window this morning. I plugged it in, and the light on the panel came on for a split second, then nothing. There's a light on the plug, and two buttons (which I assume are circuit breakers of some sort) and the light is on, so I'm certain the unit is getting power, but the air conditioner itself is not turning on.

First check if the fan is running. If the fan is notrunning is the compressor not running also, if neither is running the possiblereasons are 1, no power to outside unit, 2.bad contactor on outside unit, isthis buzzing if it is this indicates no power, 3 bad capacitor, do bothcompressor and fan humm then quit humming and hum some more, 4 high pressure switchhas shut unit down because fan wasn't running if compressor was running but notfan, if your unit has this there will be a manual reset button where the lines come out ofunit. If compressor was running and fan was not, 1 bad fan or 2 bad capacitor. Please check these followings: 1. Thermostat checks i) Is thesystem selector switch in the "Cool" position?
ii) Is the temperature set at least 3 degrees below current room temperature?
iii) If your thermostat is electronic, are the batteries charged?
iv) Some forced-air furnaces have a switch on the thermostat that allows you toturn the fan on independently of the furnace or air conditioner. This switchwill be marked "ON" and "AUTO". Does your thermostat havesuch a switch?
v) If the answer to the above is Yes, listen for the furnace fan coming on. Ifyou cannot hear the fan, go to one of the supply registers and see if you canfeel any air coming up. Is the furnace fan operating?

If everything seemsfine with the thermostat, the next step is to make sure there is power going tothe furnace.

2. Electrical checks

(A) Items to check at the furnace i) Your systemmay be equipped with an emergency shut-off switch for the furnace. If so, makesure it is turned ON. In most homes, the emergency shut-off switch looks justlike a regular light switch and will be located close to the furnace. (Tracethe wire from the switch to the furnace to make sure you have the right switch.)It is quite common for this switch to be turned off accidentally. If the switchis ON, but the fan still doesn't operate, proceed to the Items to check at theelectrical panel.
ii) Some heating systems also have emergency cut-out switches that are activatedwhen a door or service panel is removed. Often the furnace door is not replacedproperly after a filter cleaning and the cut-out switch will prevent thefurnace from coming on. Check to make sure all access doors are properlysecured and fitted. (B) Items tocheck at the electrical panel i) Thebreakers for the air conditioner and the furnace should be in the"ON" position. If a breaker has been tripped, it will be in aposition between ON and OFF. To reset, turn the breaker all the way off and thenback on. If you have fuses instead, make sure the fuse hasn't blown. If it has,replace it with the same-d fuse. If you havedetermined that there is power to the furnace but you are still not getting anyheat, select your heating fuel type from the list below and continue with thechecks. If you have discovered that the furnace is not getting any power, callyour service contractor. (C) Items tocheck at the air conditioner i) Somecentral air conditioners are installed with a switch, or electrical disconnect,mounted outside to turn off the main power to the unit. Whether or not you havesuch a switch will depend on the electrical code in your area. If you have adisconnect switch, check to make sure it is in the ON position.
ii) Is the fan running on the unit outside? (If the fan is running, you havepower to the unit.)
iii) Some air conditioners will make a little buzzing sound, even when they arenot running. Have you ever noticed this before? Can you hear it now? Summary: Ifyou have determined that there is power to both the furnace and air conditionerbut you are still not getting any cool air, continue with the checks in thisguide. If either the furnace or air conditioner does not have power, call yourservice contractor. (D) Icechecks i) Is thereice building up on the pipes connecting the furnace to the air conditioningunit outside?
ii)Touch the plenum (this is the sheet metal box that comes off of the furnace;the evaporator coil is inside). Does it feel very cold? If it does, theevaporator coil may be frozen and you'll need to call for service Hope this will help you. Good Luck.