There are three main components that could be malfunctioning if your gas dryer isn't heating properly. The igniter, gas valve coils and thermal fuse could all be the culprit, according to the 411 Home Repair website.
Most newer gas dryers and some older ones have an electric igniter that lights the gas in lieu of a constantly burning pilot light. The igniter will glow bright orange when the machine is turned on to fire the gas, but if there is no glow then the igniter has stopped working and will need to be replaced.
If the igniter seems to be glowing normally, but the gas isn't lighting then it means none or not enough gas is getting into the unit to ignite. It's easy to see if the gas is igniting because there will be a large blue flame to heat the dryer. Faulty valve coils likely cause this problem. When defective, they will not open the gas valve and therefore no gas gets in.
The thermal fuse will cause a gas dryer to stop heating or stop working all together. It is mounted in the exhaust duct and will blow if the dryer overheats. This inch-long fuse must be replaced in order to make the unit run properly again.
If your dryer is overheating it may be because lint from the loads of laundry have clogged the ventilation and exhaust system and restricted the necessary airflow to keep the unit cool.
Overheating can cause problems with your thermal fuse and potentially be a fire hazard. Cleaning out all lint from the ductwork throughout the system should prevent the problem. If it does not, then it could be a faulty cycling thermostat. This is an unusual problem, but it could cause overheating, according to the Repair Clinic website.
If your clothing smells bad when it comes out of your gas dryer, it could be a result of two different problems, according to the Repair Clinic website.
When too much lint gathers inside the traps or ducts in a dryer, the excessive heat could cause small lint fires that burn momentarily and then blow out. The smoke from these small fires remains in the dryer and can permeate the clothing being dried.
Another reason clothes may stink in a gas dryer is because products such as solvents, paint or lacquer are stored nearby. The fumes from these products tend to amplify when mixed with the gas from the dryer. This smell can end up in the clothing and be quite unpleasant. Keeping these items at least 50 feet from the dryer should resolve the problem.