Most "traditional" electric dryers basically have a heating element, a fan, a motor and a control panel. The motor turns the drum, usually via a belt. The fan blows air past the heating element into the drum. The air then flows out, through the lint filter to the back (or possibly side) of the dryer through ductwork to the outside.
Anything can go wrong, but the most likely problem is that the air is going into the room instead of to the outside. That points to one of a few possibilities (more specifics would depend on looking at the manual for the specific model):
- Air blocked from exiting the dryer, resulting in it seeping out through any cracks/gaps and, therefore, going through the control panel (condensation) and into the room.
- Ductwork not connected properly at the back of the dryer. This would easily explain the air going into the room, but not the condensation in the control panel.
- Ductwork damaged, preventing air from exiting properly. This could result in air going into the room and/or air not exiting the dryer normally and instead seeping out through any cracks/gaps.
- Ductwork not connected to the outside. Presumably accidentally (because if it was on purpose, the old dryer would have had the same problem) and the air going into the room.
Check the installation manual to see if there are any dampers, multiple venting options, etc. that might explain the problem. Also check the ductwork to make sure that it is (a) connected to the dryer, (b) connected to the outside and (c) not crimped, squashed, torn, etc.
With typical ductwork, it should be easy to remove it from the dryer. That is important so that you can clean the ductwork periodically, because no lint filter is perfect, and dryer lint fires are a very real problem. One thing to try is to disconnect the ductwork from the dryer and then turn on the dryer for a few seconds. You should get a steady stream of air through the vent. If you don't, then the problem is inside the dryer. If you do, then the problem is in the ductwork.
The ductwork should be as long as it needs to be, but no longer. That is because every extra bend can collect lint or get crushed. The ideal setup is one elbow out of the dryer, one straight length of ductwork (best is solid metal, next best is flexible metal, worst (by far) is vinyl/plastic), then another elbow to get through the wall to the outside. Sometimes the ductwork has to be more complicated, especially if the dryer is not next to an outside wall, but every extra turn is equivalent to several feet of additional ductwork, and every fan (dryer, exhaust fan, etc.) has a limited effective distance.
If the ductwork is more than a couple of feet longer than it needs to be, cut it! With flexible ducts that is very easy. With solid metal it is a bit trickier (tin snips or replace with a pre-cut shorter length) but the end result will be a more efficient and safer dryer.