LRE30757sp\00 brand new is tripping circuit breaker

Is Washer alone plugged into outlet? Unplug washer and try plugging something else in. Does anything else plugged into that outlet trip the breaker? Also Washer should be only thing that runs on that outlet. Breaker could be bad. If breaker is serotonin be good, take Washer back as you said it was new.

Breakers go bad, replace them.

Turn the handle all the way to the OFF position, then turn it to ON. If it is tripping, then turn OFF all breakers, then turn ON the main. Turn ON each individual breaker until you find the one that is tripping the main. No offense, but you should consider calling a qualified electrician.

B=b series,A=handle, one per pole,2=number of poles,There appears to be an error with the number after that, but you can look it up on their web site. The 4th position is very imortant because it tell what type of circuit it is, switch only, series trip, voltage trip etc.
The link to the Carling web site is:http://magnetic-circuit-breakers.carlingtech.com/magnetic-circuit-breaker__76.asp Click on the b series pdf file for complete details

try a new breaker, they do wear out over time

Loose connection does cause heat, and the heat may have damaged the breaker. You must use an ammeter to check the amperage drawn on the circuit. If the amperage is well below the breaker rating, then replace the breaker

It's possible that the first breaker that you said does not trip - it could be that breaker is failing to trip on a bad circuit. That is, it could be you have a bad circuit but that first breaker is not detecting it and pretends everything is OK. If your new breaker trips on the first breaker's circuit, the curcuit it probably bad and the breaker in not working properly. The most common problem for failed circuits is a stray ground wire in a box somewhere in the curcuit resting against a hot or neutral wire. You'll have to take apart every connection on that curcuit to find it. Not fun.

Arc fault breakers are definitely a pain. First make sure the receptacles are made for a 20 amp circuit. Second vacuums, Curlers,and most appliances will trip your breaker since they create an arc or a short if you will to operate. That is exactly what these breakers are made for. To stop the arc. Apparently they never really thought the whole arc fault thing through. As per code in most of arizona you only need this breaker in bedrooms where this type of appliance is not used. They also are more prone to popping so make sure you aren't running something on each of the receptacles at the same time

As seemingly with everything else, these devices were once very reliable but now fail early in life.
Assuming that this is no GFI (Ground Fault Interrupter) equipped breaker, you must  have a bad one. If it is, you may have some stray currents tripping the breaker.
While finishing up on our new home and putting breakers in the main box for the first time, one brand new breaker refused to stay set even though the circuit was OK and no loads on that branch connected at all. In the two years we have been here, we had to replace a second one acting just as you describe.