Hello. We have a Whirlpool WGD9600TA0 gas dryer that will heat sometimes but not all times. I had replaced the gas burner assembly about 2 years ago due to a broken heating element. No problems until a few months ago. That is when we noticed that the dryer would take a couple, if not 3 cycles to dry our clothes.
Fast forward to last week. No heat, no dry. I looked on the forums and figured it was most likely 1 of 3 things: the high limit thermostat, the thermal fuse, or the thermistor. I purchased these items online along with a pair of gas valve coils.
When the parts arrived, I didn't bother checking them with my multi-meter. I figured "I had them, they didn't cost much, let's just replace them." (I never replaced the valve coils) Lo and behold, HEAT!
2 cycles later, no heat. :(
I checked our venting. No kinks and no clogs. At this point, I must mention that our gas dryer does not have an external wall where it can vent. It has to go up through the wall (single-story) into the attic where it meets a dryer vent booster. This particular model has the pressure sensor installed so it knows when to turn on or off. I could feel that the unit was trying to turn, but i had a hunch that it was faulty. I removed the duct tape, and looked inside. It was caked on both sides with lint and would not rotate. I turned off the breaker and went to town cleaning it out. Even with it back on (I blew into the pressure switch), I had to help it start rotating ever so carefully. I don't think the motor is working 100% (I have a new 167 CFM model arriving soon), but it is blowing. I don't think it is blowing the rated 150 CFM, but I have no way to measure this nor do I have anything to compare it to. After the booster, the vent takes a 45-degree turn to the roof where it vents out (another 10 - 12 feet for a total of about 30 feet with the booster approximately halfway through the run). Furthermore, I went to our local hardware store, purchased a duct cleaner, and cleaned out the lower portion of the duct-work. I was sweating too much, so I didn't bother with the upper side (I will get that when I replace the booster).
I then went down and checked my old high limit thermostat, the thermal fuse, and the thermistor; all showed continuity. I then removed the new devices and checked them for continuity; all good. I replaced the backing and tried the unit again, venting through the flex hose into the garage. HEAT! 4 cycles later, no heat. :(
I put it all back together because my wife was a little surprised at how much space a dryer in pieces can take up in the laundry room... So now, from time to time, it works. It *appears* that if we wait between cycles (instead of running them back-to-back), it works. Furthermore, if we run a particularly long cycle (>= 40 minutes), it stops heating.
This happens if it is either on a timed cycle or a sensing cycle.
What I do know is that the gas valve is not opening to allow gas to flow. When it is heating, I can hear the gas valve opening, burning for a few seconds and then shutting off (and then repeating). When it is not working, I am not hearing the valve open at all. I also know that the heating element is always on (when it is on a drying cycle, not *ALWAYS* on) - I have seen the bright orange glow while peering through the vents on the back cover.
I have tried to do my homework, but I am obviously missing something. Are there other parts I am overlooking? Your expertise and advice is greatly appreciated. Thanks!