Kenmore 90 Series Gas Dryer No Heat. Have replaced both Coil Valves, and thermal fuse. Gas ignites, runs for 15 seconds then turns off. All ducting is clean. I bypassed thermostate same problem. I also bypassed the sensor radiant and the pilot light comes and remains on on but does not ignite. What is the next step?

Does your dryer have power? If yes, then check (1) the flow of air outside the house from your dryer tube and (2) your circuit breaker panel for each circuit in the house (I've not seen fuses/breakers built into dryers -- though that could change). Then check (3) your heating element, (4) thermostat, (5) high-temp thermal cutoff switch, and (6) for debris in the air flow path to / from from the centrifugal fan.
Here are 3 resources that helped me with my Kenmore Series 90 Dryer:
No Heat? - http://chris-doityourselfrepair.blogspot.com/2011/10/kenmore-90-series-model-110-clothes.html
Looking Inside My Dryer - http://chris-doityourselfrepair.blogspot.com/search/label/Disassembling%20Kenmore%20Dryer%2090%20Series
Exterior Exhaust Duct - http://chris-doityourselfrepair.blogspot.com/2013/08/cleaning-out-and-replacing-exhaust-duct.html

It could be several other things thermal fuse, thermal cut out, hi limit thermostat, dryer coils, heat sensor,or igniter. All of these parts are inexpensive and easy to test and replace.There is a video at t http://appliancehelponline.com/gdryertroublevideo.html his will walk you thru the troubleshooting of these components. It may be a different model but the troubleshooting will be the same.You can also enter your model # for diagrams and illustrations. All parts come with installation instructions. Not all models are available. If you need help disassembling your machine there are videos of this also for most styles.

But the clothes drum is turning? Running? If you have a electric dryer you need to replace the heat elements. If gas you need to replace the igniter coil.

Check the following areas to combat this issue. the most common problem spot will be a blown Thermal fuse.


1. Gas valve coils
Igniter glows, then shuts off without igniting gas - the problem is probably with defective coils (black, located on top of the gas valve). It is recommended to replace all coils (usually two or three) if found defective.

Note: Sometimes the whole gas valve may be defective, thus not letting the gas out. However, this problem is not common.

2. Thermal fuse
Most dryers have a thermal fuse, which burns out when the dryer overheats, in which case the dryer will either not run at all or stop heating. The fuse is usually located on the vent duct, inside the dryer. A blown fuse will show no continuity when measured with a meter. Before replacing the fuse, make sure the blower wheel is not broken or clogged, and there is nothing blocking the venting.

Note: It is recommended by most dryer manufacturers to replace a hi-limit thermostat when replacing a thermal fuse.

3. Igniter
Igniter may burn out or break. Replace the igniter if found defective.

Note: Igniters are very fragile and break easily. It is recommended to handle the igniter only touching the ceramic part of it (usually white in color).

4. Flame sensor (or radiant heat sensor)
Replace the sensor (located near the igniter) if found defective.

If your dryer doesn't heat, check these:

Igniter
Gas valve coils
Thermal fuse
Igniter Modern gas dryers use an electric igniter to ignite the gas from the gas valve. When it's working properly, the igniter glows bright orange. When it burns out, the dryer tumbles but there's no heat because the gas can't ignite. When the igniter burns out, you need to replace it. If the igniter is held by a tension bracket, you very well may need to replace the bracket too.

The igniter is inside the dryer housing, near the bottom front, usually in a cone-shaped metal tube (the force cone). It's about 2 inches long. It's mounted to the far end of the burner tube, and it has two wires attached to it--or to the tension bracket, if there is one.

Gas valve coils Watch the igniter. Does it glow bright orange, then shut off without igniting the gas? (When the gas ignites there's a large blue flame.) If so, there may be defective coils on the gas valve. Mounted on the top of modern gas valves, there are black electrical coils. The coils, when energized, open the gas valve. If one or more of the coils are defective, the valve doesn't open and the gas cannot ignite. Because it's often difficult to properly test the coils, it's usually best to replace both (all) of them at the same time.

Thermal fuse On many dryers, there's a thermal fuse (a heat-sensitive fuse that blows if the dryer overheats) mounted to the exhaust duct inside the back cover panel. The fuse is about an inch long. It's usually embedded in black resin and mounted in a white plastic housing.

thermal fuse is bad. replace fuse. clean out vent duct. thermal fuse usually blows when there is restricted air flow over heating element.

Check the following to address the non heating issue


1. Gas valve coils
Igniter glows, then shuts off without igniting gas - the problem is probably with defective coils (black, located on top of the gas valve). It is recommended to replace all coils (usually two or three) if found defective.

Note: Sometimes the whole gas valve may be defective, thus not letting the gas out. However, this problem is not common.

2. Thermal fuse
Most dryers have a thermal fuse, which burns out when the dryer overheats, in which case the dryer will either not run at all or stop heating. The fuse is usually located on the vent duct, inside the dryer. A blown fuse will show no continuity when measured with a meter. Before replacing the fuse, make sure the blower wheel is not broken or clogged, and there is nothing blocking the venting.

Note: It is recommended by most dryer manufacturers to replace a hi-limit thermostat when replacing a thermal fuse.

3. Igniter
Igniter may burn out or break. Replace the igniter if found defective.

Note: Igniters are very fragile and break easily. It is recommended to handle the igniter only touching the ceramic part of it (usually white in color).

4. Flame sensor (or radiant heat sensor)
Replace the sensor (located near the igniter) if found defective.

Check the following to address this issue..


1. Gas valve coils
Igniter glows, then shuts off without igniting gas - the problem is probably with defective coils (black, located on top of the gas valve). It is recommended to replace all coils (usually two or three) if found defective.

Note: Sometimes the whole gas valve may be defective, thus not letting the gas out. However, this problem is not common.

2. Thermal fuse
Most dryers have a thermal fuse, which burns out when the dryer overheats, in which case the dryer will either not run at all or stop heating. The fuse is usually located on the vent duct, inside the dryer. A blown fuse will show no continuity when measured with a meter. Before replacing the fuse, make sure the blower wheel is not broken or clogged, and there is nothing blocking the venting.

Note: It is recommended by most dryer manufacturers to replace a hi-limit thermostat when replacing a thermal fuse.

3. Igniter
Igniter may burn out or break. Replace the igniter if found defective.

Note: Igniters are very fragile and break easily. It is recommended to handle the igniter only touching the ceramic part of it (usually white in color).

4. Flame sensor (or radiant heat sensor)
Replace the sensor (located near the igniter) if found defective.

For a gas dryer, check the following


1. Gas valve coils
Igniter glows, then shuts off without igniting gas - the problem is probably with defective coils (black, located on top of the gas valve). It is recommended to replace all coils (usually two or three) if found defective.

Note: Sometimes the whole gas valve may be defective, thus not letting the gas out. However, this problem is not common.

2. Thermal fuse
Most dryers have a thermal fuse, which burns out when the dryer overheats, in which case the dryer will either not run at all or stop heating. The fuse is usually located on the vent duct, inside the dryer. A blown fuse will show no continuity when measured with a meter. Before replacing the fuse, make sure the blower wheel is not broken or clogged, and there is nothing blocking the venting.

Note: It is recommended by most dryer manufacturers to replace a hi-limit thermostat when replacing a thermal fuse.

3. Igniter
Igniter may burn out or break. Replace the igniter if found defective.

Note: Igniters are very fragile and break easily. It is recommended to handle the igniter only touching the ceramic part of it (usually white in color).

4. Flame sensor (or radiant heat sensor)
Replace the sensor (located near the igniter) if found defective.


For a electric dryer, check the following

1. No power to the dryer
Make sure there's power getting to the dryer. Check for tripped circuit breakers or blown fuses. An electric dryer uses two circuit breakers or fuses, and if only one of two is tripped or blown, the dryer might still run but not heat. Sometimes the power cord disconnects or burns at the dryer, if this is the case, the wiring and the terminal block must be repaired or replaced.

2. Heating element
A burned out heating element will show no continuity when measured with a meter. Replace the element if found defective.

3. Thermal fuse
Most dryers have a thermal fuse, which burns out when the dryer overheats, in which case the dryer will either not run at all or stop heating. The fuse is usually located on the vent duct, inside the dryer. A blown fuse will show no continuity when measured with a meter. Before replacing the fuse, make sure the blower wheel is not broken or clogged, and there is nothing blocking the venting.

If it's gas, the coil valves get weak and are unable to hold themselves open when hot. First, check the exhaust vent. If it's clogged, it can't remove heat and it will shut off prematurely. Most likely the coil valves though.