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My gas dryer tumbles, but has no heat. After reading this forum, I think problem may be the igniter. If I can access it, I can test it for continuity. Can anyone offer advice on the following two methods to access igniter:
1) the gas line comes into the back of the dryer at the lower left hand corner (as seen front the front). On the lower rear of the left side panel, there is a 4" diameter circle in the sheet metal that can be punched out with a hammer. Can I access the igniter by punching out this circle? If I punch it out, how do I re-secure afterwards? Does it present a safety (fire?) issue if I don't close up this 4" opening once my dryer is working?
2) I know how to remove the entire front panel of the dryer. Is this best way to access the igniter? I am worry that once I remove the front panel, I may mess up the seals/gaskets that are used to seal the front panel and the drum. Is there a high risk that the heat will escape from the seal between the front panel and the drum when I reattach the front panel to the drum?
Thanks for any help.
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Rank: Advanced Member
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The best way to get to everything is through the front. Removing side vent knockout will only get you a look at the burner tube and that won't do you any good. If you simply remove the front panel, the drum seals won't fall out or anything like that. Once removed, you can see the entire burner assembly and can work on most of it without even removing the drum. Check for voltage to the burner assembly as the no heating may not be the igniter, but rather the high limit thermostat, so do some checking before ordering parts.
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Thanks for your reply, Brian.
I've never done this before, so it's very reassuring to have your comments regarding the drum seals.
Interesting that you mention the thermostat. Another problem that I had with this dryer--just prior the "no heat" problem--was that it seemed like the auto dry wasn't working. The dryer would, at times, keep on running with no change in the humidity setting at control knob. In looking at the parts list, it seems like that the moisture sensing function is performed by the "safety thermostat" located at the top of the drum, and acessible by lifting up the top panel of the dryer. Is the safety thermostat responsible for moisture sensing? How do I test to see if this part is good? Is the safety thermostat what you called "high limit" thermostat? (EDIT: I just put an ohmeter across the two terminals of the safety thermostat with it installed into the drum. It is reading zero ohm.)
Also, could the "control thermostat", located at motor, also be the cause if voltage is not reaching the igniter?
EDIT: Oh, one more question: I couldn't see a "thermal fuse" parts in parts list or break-out diagrams, so I assuming that this dryer does not have one. If it does, could someone point me to where I can find it, so I can check it. I've looked in the exahust vent at the back of the dryer and didn't see anything. Thanks.
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Rank: Advanced Member
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Have you verified no voltage to the burner assembly? Based on your measurement, the safety thermostat appears to be OK which would leave the control thermostat in the front as the other likely failure point. Your dryer does not have a thermal fuse like some of the others so you won't find one anywhere. As for the drying issue, I cannot find a wiring diagram on your dryer that I can actually read so how it auto drys depends on whether or not you have moisture bars mounted to the inside of the front panel by the lint screen. If you see two silver bars just on the inside left, then your dryer uses a control board, where as if you don't, then it is using the control thermostat for that feature. The work off of a different principle, but both accomplish a very similar function. Verify the control thermostat is ready 0 ohms, and check for voltage to the burner itself (this may take some creativity) so we can determine if the failure is before the burner, or at the burner itself.
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Rank: Member
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Brian, I did not check the voltage at the burner yet. I will try to do this when I can set aside a couple of hours to open the front panel and check inside. I did take a photo of the wiring diagram attached to the back of the top panel, and have posted it here: Frigidaire gas dryer FSG747GES1 wiring diagram web.jpg photo - andrew99 photos at pbase.comIt appears (to me) that the control thermostat may be the part responsible for regulating the drying time in auto dry mode. (I guess the dryer uses temperture sensing instead of moisture sensing?) I can check this part for continuity, but is there anyway I can test it to see if it is failing with respect to the auto dry function? I'll try to figure out a way to test the power path to the igniter and the coils when I get in there. I am guessing that I should not try to jumper the door lock and try to power the thing up with the front panel open. I am hoping that the igniter will be obviously bad (open circuit) to make the trouble-shooting easier. Of course, I would be assuming that the probability of a second malfunction, other than the igniter, to be small. Not sure if this is a good assumption. I'll post again after I open up the front panel and check things out. Please feel free to provide any trouble-shooting hints or general thoughts if you think of something. If anyone else reading this has comments, please chime in also. I will be checking the forum before I open up the front panel. Thanks for all the help so far. It's greatly appreciated.
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Rank: Advanced Member
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Thanks for the wiring diagram. Your dryer uses the operating thermostat for the auto dryer feature so it really doesn't know if the clothes are damp or not. How it works is as long as the clothes are still damp, the moisture from the clothes will help keep the thermostat cool enough to keep it closed and the burner on. Ad the clothes begin to dry, the moisture or humidity level inside the drum decreases and the thermostat will open shutting off the burner. When this happens, the timer motor is turned on via the violet wire connected to the thermostat. So the idea is when the clothes are damp, the timer motor will be off and the timer won't move. As they dry, the timer motor will be powered and the cycle will continue. So if you are having auto dry problems too, the first thing I would check is that you have good airflow and a clean vent all the way to the outside. If that looks good, then you can check the violet wire from the thermostat to the timer and make sure it has continuity. Then when you get the burner back working, then you can monitor the timer and make sure it stalls at the beginning of the cycle when the clothes are still wet. If not, then it's time to search out a solution to that problem. But lets get some heat going first.
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Rank: Member
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Well, I have not opened the front panel yet BUT ....
I have new trouble-shooting info. I ran the dryer on timed dry at regular (high heat), and looked down into the dryer from the top, with the top panel lifted out of the way. Approx. 7 secs after the dryer started, I can see an orange glow in the inside bottom front left corner of the dryer. The glow remains for about 5 secs and then goes dark, and doesn't come back on. I turned the dryer off after about 30 seconds.
So it appears that voltage is at least getting to the igniter. Does a "bad" igniter still get hot, but only for a short duration? Or is this a symptom of the coils being bad? (I see that the booster coil is connected in parallel to the igniter.) If this is a bad coil symptom, I am wondering if I should go ahead and buy a new coil set first, and have it available when I open up the front panel. Thanks for any advice.
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Rank: Advanced Member
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This is usually a symptom of bad coils, because if the igniter is glowing, then everything else is working fine. This could also explain the auto dry problem, because usually before the coils completely fail, they begin to have problems with holding the valves open and begin to work intermittently. Having a new coil set may be a good idea and given the age of the dryer, probably a needed investment.
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Rank: Member
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Well, this certainly makes me feel even better if the bad coils could tie in with the auto dry problems I was having. So, if I understand it, the bad coils would cause interruption in the heating and this interruption would allow the exhaust air to cool down, so it doesn't trigger the control thermostat--even though the heat inside the drum gets quite hot.
I will go ahead and buy the coils first, before opening up the front panel. I'll report back afterwards.
Thanks for all your tremendous help, Brian.
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Rank: Advanced Member
Groups: Senior Expert
Joined: 12/2/2007(UTC)
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Sure thing. Let us know how it turns out.
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