The following link explains how to troubleshoot a dryer
not heat problem:http://www.fixya.com/support/r630242-dryer_runs_but_not_heat
Most dryer heat related problems are attributed to poorly installed, kinked or clogged exhaust vent ducting. Pay particular attention to the section that discusses ventilation and make sure your dryer interior and ducting are clean. Leaving a dryer in a clogged condition will not only decrease the drying efficiency
of the appliance, it will also cause repeated failures of any components you may replace and is a fire hazard.
The first thing you need to check is the wall receptacle for the proper input voltage. A reading across the two hot leads (left and right slots) should read 220-240 VAC. If this reading is incorrect, check your breaker panel. Some homes
have the dryer circuit on two breakers, vice one single 220 breaker. If the voltage at the receptacle is good, unplug the dryer and remove the cover on the terminal block in the back of the dryer. Plug the dryer back in and take the same voltage check at terminal block across the RED and BLACK wires. You should see 220-240 VAC if good. If the voltage is bad at the terminal block, but good at the wall receptacle, you have a bad power cord. If the voltage is good at the terminal block, then the problem is internal to the dryer.
NOTE: The reason a dryer will still run if the input voltage is incorrect is because the dryer drive motor only uses 110-120 VAC, while the heating circuits require the full 220 service
. So, if you are missing a portion of your input voltage, the dryer may exhibit the symptoms you have.
If you have any questions about this repair, or require additional assistance please let me know.