We had a Whirlpool Duet H2 washer for 8 years. It just broke, so we bought a Kenmore Elite He5 Steam Model from Sears. After the installers left, I ran my first load and water ran all over the floor. Sears sent another person out the next day, and this person told us that the problem was that our drain line was not able to handle the additional pressure that this model has. Sears further told us that we have to buy a low end washer to stay with this low pressure output. I can't believe that these new washers wouldn't work in a home where previous Whirlpool Duet worked. What do you think?

I think you better do what the rest of us do whan we have the same problem.
Today's more powerful pumps can overpower a drainage system that's been working for years. When the happens we advise making your washer drainage a closed system by connecting the washer hose to the stand pipe using a compression fitting, (see image) or simply duct taping it. Any thing you can do to make a air tight connection. The washer pump will force the discharge through to the house main. I have had one on my stand pipe for the last 10 years an three washers with bno backups nor problem to the washer.
In addition, in all the hundreds of askers we have advised to do this we have never- ever had a complaint back. Good luck, Tom