My dryer takes 3 hours to dry a load of clothes.
Roxanne for Model Number DBSR453EB2WW
Answer This doesn't sound like the dryers' fault at all since the clothes can be air fluffed dry with no heat at all in a couple of hours time. This has to be a ducting issue. You see, the heat doesn't dry the clothes. If the heat dried the clothes, you could put them in the microwave and have them done in a few minutes. All this will get you though is hot, wet, clothes. The air flow is what actually carries the moisture away from the clothes. The heat is an assistance to the air flow so the air flow can more easily carry the moisture away from the clothes. If the unit has an air flow restriction, the thermostats will quick cycle and will take a long time to reset and turn the heating element back on. This always makes the customer think the unit isn't drying properly.
Even if the unit has worked in the installation for a long time, this is no indication that there hasn't been a change with the ducting. The first thing I would do is check outside at the flapper door. If the flapper cannot open, or if there is a screen at the flapper that is stopped up, this will cause the issue. If the ducting is flexible, it can fill with water under the house or the flex duct can be crimped behind the unit if the unit has been pushed back against the wall.
The exhaust cannot exceed the equivalent of 25 feet. What this means is that each 90° elbow slows the air flow the same as 6 feet of straight ducting. So, you have to add 6 feet at every 90° turn plus the straight footage. The dryer drum is riding on felt seals. If a little too much back pressure is built up, the lint, heat, and moisture will simply blow past the drum seals back into the cabinet. This is actually where the air is taken into the unit and also where the thermostats are located. This causes the thermostats to open prematurely and this will extend the dry cycle. The exhaust should be a 4 inch diameter rigid, non-flexible aluminum duct that is as short and straight as possible. You see, the shorter and straighter the duct is, the faster and easier it is for the unit to rid itself of the heat, lint, and moisture and the clothes will dry faster, the unit will use less electricity, and the dryer will last you longer since it isn't running a long time putting wear on the mechanical and electrical parts.
All manufacturers strongly recommend against the flexible ducting whether it is plastic or the foil type. The flexible ducting crimps off the air flow too much when the unit is pushed back into place. It also holds lint which, when ignited, goes off like flash paper and will cherry inside the duct. The flexible duct will just melt through, (yes, even the foil type will just melt), and then you have the lint "cherryed up" in the floor behind the dryer or in the crawlspace.