Gas Dryer Heating Issue Troubleshooting

Written by Jonathan Gidley Wednesday, 11 May 2011 04:39

WARNING!!

WARNING!!

Working with gas dryers can be dangerous. Always make sure your dryer is unplugged before taking the dryer apart. Do not remove gas lines unless you have knowledge on testing for leaks after you've re-applied the gas line. If you smell gas and aren't sure how to find the leak shut the gas off immediately and call a professional to avoid injury or possible death. Use extreme caution to protect yourself and those in your home.

The first thing we are going to look at is all the parts in your gas dryer working to give you heat. Make sure you get your model number off of the tag stamped on the dryer to get the correct parts for your dryer when you determine the problem. There is a power inlet cord that feeds 110-120vac electricity to all the parts in the dryer. The timer or control board is what is connecting the power to the appropriate parts through the cycle. The parts giving you heat vary model to model such as the number of thermostats, etc.. All are similar on in the order of operation. There is a gas valve that delivers the gas when the two wire coil of the two coils mounted on the top of the valve is energized once the thermostat mounted to the side of the flame tube reaches the correct temperature. The three wire coil mounted to the top of the valve is energized when the dryer timer is set on a heated selection and you press start, connecting power to the ignitor. There will be safety fuses to act as fail safes if the thermostats that control the temperature malfunction. The parts giving you your tumble and air flow during the cycle are the belt that runs over the tub, under the tensoiner pulley to hold the belt tight, and onto the motor pulley which gives you your spin. On the other shaft of the motor is the blower wheel that pulls the hot air over the clothes and out the vent giving the dryer the ability to dry the clothes. The parts ensuring a smooth sounding tumble will vary model to model. You could have two rollers on the back, plastic glides snapped to the tub, and a piece of felt on the front panel. Felt with glides on the front panel, rear bearing cup and assembly. Four rollers on the front and back panel with felt on the tub, etc..

Your gas dryer will not heat:

First lets turn your gas dryer timer knob to a heated selection and turn it on. Almost all of your gas dryers have a small plastic piece located on the front panel that you can remove to check out whats going on during the cycle. You'll be initially looking for the glow of the ignitor. If your dryer doesn't have a peep hole then you'll want to listen for a clunk when you press start on the gas dryer. If your looking in the peep hole, the dryer is running on a heated selection, and your not seeing a glow from the ignitor or aren't hearing a clunk when you first press start then you've got one of several problems. You'll need to figure out how to get into your dryer, we show you these processes in videos on our site. On gas dryers the thermal fuse could be burnt out and the dryer can still operate. If you need help determining which part is your thermal fuse you can take your model number to our site and enter into the model search for a breakdown of the parts inside to get some direction. What i can tell you is that it will have only two wires running to it. Once you've located your thermal fuse you can run an ohms/continuity test on the fuse. If your getting no ohms/continuity through the fuse then replace it. Before you put the dryer back together you'll want to get it together enough to run it on a heated selection without the vent on press start. With an oven thermometer or a laser thermal heat tester, test where the air is coming out of the back of the dryer after it has heated up to make sure its holding the correct temperature. You want 155-170f deg coming out of the back. If your gas dryer is getting much hotter than that then you'll need to replace the cycling thermostat that controls the heat. This thermostat is usually mounted on the blower housing with four wires running to it. The leading cause of the thermal fuse issue is a clogged up vent. So make sure that you clear the vent throroughly before you put it into regular use.

If the thermal fuse gives an ohms reading or continuity, you'll need to get the front panel to a place where you can plug the door switch back in, make sure there are no power wires grounded, get a feel where all exposed wires that could shock you to avoid touching them, and plug the dryer in. Some dryer have an idler arm safety switch that will not allow you to start the dryer without the belt on to engage the switch, others don't. If your dryer does, disengage the switch, put the timer to a heated selection, and start the dryer. Now remember this is all relative to pressing the start button and hearing no clunking sound, so lets move on. If all of the parts to this point check out. Power test the wires running to the harnesses on the 3 wire coil sitting on top of the gas valve for 110-120vac with the dryer running on a heated selection. If your getting power at the 3 wire coil and no ignitor glow, replace the coils.

On the other hand, if you're hearing a clunk when you press start:

This could be the ignitor, the gas coils, or the flame switch. This can be a bit tricky. If your dryer has a small plastic tab you can remove with the dryer together you can look inside to see if the ignitor is glowing or not. If the ignitor is not glowing. Unplug the dryer, take the dryer apart, tub out, door switch still plugged in, timer set to a heated selection, plug the dryer back in, and the dryer turned on. With a power tester check for 110-120vac at the 2 wires running to the ignitor. If your getting 110vac to the ignitor and no glow replace the ignitor.

If you are getting a glow from the ignitor but the gas never comes on:

You'll need to take the dryer apart to a point that you can power test at the flame switch. The flame switch is mounted on the side of the flame tube and is a black square part with two wires. If you get 110-120vac at the thermostat the ignitor glows and the gas never comes on and you still have the same power at the thermostat when the ignitor shuts off replace the flame switch.

When the flame is coming on and shutting off after a short time running:

Note: the flame should be on for 1 1/2-2 min when it 1st start, then come on to hold the correct temperature, 155f-175f deg if testing at the vent, thereafter. If the ignitor is glowing the flame is coming on and shutting off before getting hot enough, or not coming back on at all after the 1st time, replace the gas coils.

If your dryer isn't getting quite hot enough, or drying well enough:

First clear your vent out thoroughly to make sure its not just an air flow issue.
The cycling thermostat could be the problem. You should test with an oven thermometer or a laser thermal heat tester at the back of the dryer where the air comes out. You should be getting 155-170f deg with no clothes in the tub. If its just not quite hot enough replace the cycling thermostat.

If the tub is not spinning or your getting noises while tumbling:

Take the dryer apart and check the belt, all the rollers, glides or felt, and the tensioner. Your best off if your replacing one to replace them all while your in there since these are parts that endure normal where and tear. Since most models are set up differently inside you'll need to do a model search(which you can do at our site) for a parts breakdown to get a better idea of what is giving you a smooth sounding tumble. Since this is an article generally for the heating issues, i'll leave it at that. Once again we have videos on gas dryer repair at our site if you need help. Good luck on your repair.