Hi There,

The bottom soleplate on the Dyson DC14 can sometimes cause this to happen. Especially when you say that only after you installed a new belt, as this means the bottom plate was removed. It's incredibly easy to put the bottom plate back on the wrong way, and when this happens, the brushes don't hit the carpeting as well.

Here's how you can see if the bottom plate is put on correctly:
Possible Problem #1. The first problem is extremely common. In fact, we probably see between 2-3 of these problems every week. It mostly happens after people take the bottom plate off the vacuum in order to clean the roller brush. What happens is when they reinstall the bottom plate, they put it on on incorrectly. It's actually very easy to do. When the bottom plate (soleplate) is installed wrong, there will be a gap between the bottom plate, and the agitator housing, or the purple tray the roller brush sits in. This will cause the soleplate to be a few inches higher off the ground then it should be, preventing the brushes from even hitting the carpet. This makes it seem to the user that vacuum has lost suction power because without the brushes hitting the carpet, the machine will not pick up very well on floors, but when they use the attachment hose there's plenty of suction power.

Here's a picture of the WRONG way to install the bottom plate. Notice the gap in between the two housings:



Here's another picture, that is the RIGHT way to install the soleplate:

I would say probably 6 times out of 10 this is the problem with the customers machine. If you checked the soleplate and it is installed correctly, move on to the second possible problem.

If this was not the problem, please just add a comment to this repair, and I'll be more then happy to walk you through some further more advanced diagnosing.

If this was helpful, please be so kind and rate my repair or leave me some feedback. This is greatly appreciated by the Fixya community.

Thanks again,

Chris Jones
GoVacuum.com