Brand new. Why doesn't it work and won't mist?

Best solution is to take it back to the retailer for warranty repair or exchange.

I have a similar problem. I found a crack in the tank. I am trying to find out if it is cheaper to replace the tank, or just buy another one. I have tried other types and like this one the best.

it has a quiet operation when you got it brand new did it put out mist

if you can hear the fun noise, you need to check major circuit, should be bad capacitor. if no noise at all, replace the fun.
actually they have very good customer service. just contact by email or phone, tell them what's happened, they should give you a RMA number, put the tank cap and cut small piece of power cable, send to them, you will receive a brand new humidifier within couple weeks. even your machine slightly out of warranty.

Hi, have you given it a while? That humidifier usually takes about 10 minutes to get going. After 10 minutes or so you should be able to feel the warm mist coming out, and soon after you should feel a difference in the moisture in the air.

Hi, unfortunately there's nowhere to purchase a replacement tank online. You can buy a new humidifier from Walmart for $25 when they replenish their stock:
http://www.walmart.com/ip/Sunbeam-Warm-Mist-Humidifier/12356384
Or you can get one for $29.29 branded as Holmes instead of Sunbeam from DrillSpot.com:
http://www.drillspot.com/products/1347166/jarden_consumer-heater_hum_swm5251-um_small_room_warm_humidifier
eBay also currently lists 3 of these humidifiers, being sold for $34.99 each (also branded as Holmes):
http://shop.ebay.com/?_from=R40&_trksid=m570&_nkw=swm5251&_sacat=See-All-Categories

If you can see the mist, then, it is working. The outlet
port of your humidifier could be closed/stucked up/clogged. Please check this the outlet port.