Whirlpool WED4900XW. The design has remained virtually unchanged for four decades or more. Parts are readily available, but rarely needed, because the bugs got worked out years ago. Every repair person in the world can fix it in his or her sleep -- but you probably never will need more than a belt replacement. Here is a link that might be useful: Also sold under other brand names, including Kenmore

Thank you asolo and fordtech. I got all excited. DH and I opened the window and he stuck his hand down the vent and extracted a golf ball size lint ball. Wasn't magic. There is plently of (cold) air going through the vent when the dryer is on. Then we tried fordtech's plan. Alas, there is no option "system check". There is a choice: "Before you call for help". I already did that today and the choices for an electric dryer are to check the circuits (I did) and check the vent (see above). Any other hints from anyone are welcome. Via internet sign-up, Sears can come for 65.00 in another 12 days. A city-wide outfit I clicked on-line can come tomorrow (if I can have them) for 89.00. Money isn't the issue for that difference but I am wondering about the skill level of all these people. Everyone seems to service everything so how deep could their knowledge be. (On the other hand Time-Warner fixed the Turner Movie Channel today that has been broken ever since I can remember, even pre-renovation. Turns out a little tiny part of the wire in the splitter had not been stripped. Doesn't sound right to me since pre-and post-renovation would have had to be the same problem. But channel works now so I can't complain.) Thanks.

I have the LG DLG2251W and this has been an ongoing problem. They sent me a brand new dryer - had a repair guy come out and he couldn't figure out why it wouldn't dry my clothes. He replaced the motherboard. Came back a second time because it still wouldn't dry my clothes (maybe 50% of the time it would work), and he couldn't figure it out again. So they gave me a brand new dryer. Same problem. All my ducts are brand new. There are no obstructions. THIS IS AN LG DESIGN FLAW. Google "lg dryer spins but no heat" on you tube and the guy explains how to reset the overheat sensor / safety sensor. You probably don't need a new thermostat. I can't believe I have to take apart my machine to find a safety sensor to reset it every time I have this problem (I have yet to figure out where it can be located on my model)... on a $1,000.00 machine. I have a cottage with a $300 Kenmore dryer. Guess how many problems I have with that machine? Nada. None. Zilch. Wanna throw a dry piece of clothing in your LG dryer for a few minutes to get the wrinkles out? hahahaha so funny, think again. Sensor or manual setting, heat does not work. LG seriously needs to fix this problem. I have no problem with their washing machines, but I would never buy an LG dryer again. A waste of money when you consider the HOURS I spend attempting to dry a single load of laundry. What a waste of electricity (on a gas dryer) and money down the drain on a piece of garbage. I can only imagine how much $$ repair guys are making off of these machines that have an obvious design flaw. Avoid LG dryers AT ALL COSTS. The problem isn't specific to any model, it's all their dryers.

IMHO, PVC is the wrong material, 3" is too small, and 40' is too long. This arrangement will give you trouble -- quite possibly dangerous trouble. Suggest complete re-think about your options.