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Our gas dryer now takes hours to completely dry one load. After following much of the troubleshooting on this site, we replaced both coils. Still the same operation as before, which is:
. Drum turns
. Glow burner gets white/hot
. Initial Flame comes on
. no main flame ever comes on
We did the 5 checks (found elsewhere on this site), even verified that the flame sensor opens (starts closed, but goes to 120V after the initial flame comes on).
We also vacuumed out the lint area inside the dryer, the exhaust vent tubing, and the impeller of the dryer.
The old coils both ohm'd out OK, but replaced anyway since some folks mentioned they might be weak under load.
What else can we check?
If the valve is next, is there a rebuild kit for it? or a way to salvage the valve body that we have?
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What did you mean when you said: initial flame and main flame?
There is only one flame which can be Off or On.
Make sure the gas shut off valve behind the dryer is completely open.
Gene.
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Rank: Member
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Hi Gene, thanks for the reply!
I checked the valve behind the dryer and it is in the full open position.
I agree there is only one flame. I thought it might have two intensities because there are two coils on the gas valve body. By "initial" and "main" I was referring to two levels of flame intensity - caused (I thought) by the two coils/valves being activated at different times (I guess I don't understand why there are two coils on the valve body).
I guessed the initial flame should come on, then, when the flame sensor detects that the gas is burning, the main (second) coil/valve would then activate and increase the flame. Kind of a safety thing, so we don't turn on a high volume of gas if there is no flame.
What other things can I check?
Thanks again.
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Rank: Advanced Member
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There are actually 3 coils. The one with the 3 terminals has 2 coils inside. They all are engaged together as soon as the cycling thermostat closed (pretty loud click). See the attached diagram. The flame sensor stays closed to provide the power to the igniter. As soon as the igniter reached proper temperature (gas flows and the flame is on), the flame sensor opens and the igniter goes off while the flame stays on. The flame goes off as soon as the cycling thermostat reads the set temperature and opens the circuit to the coils. How long the flame stays on? Does it go on every time when the igniter goes on? Gene.
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Rank: Member
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Hello Gene.
I turned the dryer on with nothing in it. I watched (took video actually) for the first 5 mins of operation. The flame stayed on the whole 5 mins, then I stopped watching, and turned off the dryer.
How long should the flame stay on with an empty dryer?
I will check the flex line between the gas supply valve and the dryer, perhaps it is restricted in some way...?
What else can I check?
thanks again!
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Rank: Advanced Member
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Dave,
Do you know where and how far the dryer vent line goes?
Also it is more reliable to redo this test with some wet clothes inside and watch it for at least 3 flame cycles.
Gene.
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How long (in minutes) should I expect a flame cycle to be? 10, 20, 50? The vent goes to the nearest wall on the left of the dryer, and out to the backyard (thru the wall), so maybe the exhaust run is 2.5 or 3 ft total. The video is here: http://www.youtube.com/watch?v=eFKHnFyPVeQ
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Rank: Member
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Thanks Gene!
Your questions indicated to me that we had some sort of flow blockage or restriction. Today, I took the valve body off the dryer and inspected it. The exit orifice for the body had a small amount of build-up causing the diameter of the exit orifice to be perhaps half as big (or less) as normal. I used a toothpick to clean out the gook, it was soft. After reassembling the unit, the flame works very well now! We watched as the empty dryer ran maybe a minute or two at most before the cycling thermostat kicked in and shut off the gas.
Thanks for your help and suggestions!
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Rank: Advanced Member
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You are welcome. I'm glad you were able to fix it.
Happy Holidays!
Gene.
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