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Old GE Dryer Gas Coil Issue

ttocsic

Premium Member
Joined
Jul 11, 2019
Messages
13
Location
New Jersey
Model Number
DDG7200NMLWH
Brand
GE
Age
More than 10 years
This all started with intermittent heat. Igniter would glow, some buzzing from the coils and a click. Maybe flame maybe not. I guessed that the coils were the issue. From what i understand these are the older "K"(?) style coils. See photo. I ordered a kit and had to fumble for a while since the wiring harness, wire colors and connectors didn't match exactly but i think i got it wired up correctly.
Once it was all back together, and i attempted a cycle, the igniter glows, i hear a little buzzing from the coil (the larger, double coil, i think), there's a click and i get a burst of flame in the burner but only for a split second. The flame goes right out. A few moments later the sequence repeats. Glow, click, woof and out. This isn't what I'm seeing described as an issue with the flame sensor because there is some amount of flame, albeit only for a moment. Its also not what i was seeing before which was a hit or miss flame entirely.
With these style coils, there isn't a sleeve to lose, right?
From what I've read, the polarity to the coil doesn't matter. Is that true?
Is there a possibility that the way i physically installed the coils is causing the issue? They were a little difficult to press into place, though this issue seems more electrical than mechanical.
The larger (double) coil seems to heat up a bit during the cycle. Is that normal? Could something else be causing this?
I tested the flame sensor with a meter and i get continuity. So what would cause the valve to open and then shut almost immediately after the flame lights?

Any and all help is appreciated. .

I just had a thought that maybe the polarity does matter and that the stacked coils are working against each other. I'm going try reversing the wires on one of the two and see what happens.
 

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rickgburton

Appliance Tech - Moderator
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Can you take a pic of both coil assemblies and any rewiring instructions and post them here?
 

ttocsic

Premium Member
Joined
Jul 11, 2019
Messages
13
Location
New Jersey
Rick,
See attached.
What exactly are you looking to see so I can take a good pic.
This is the kit I bought:

No instructions were supplied with it so I matched what I could. Here's what I came up with.
Secondary coil
Old: black and white wires
New: blue and white wires

Primary (stacked) coils
Top coil old: Orange and black
Top coil new: blue and black
Bottom old: white and red
Bottom new: Black And white.
 

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rickgburton

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Why did you need to the separate the coil kit? It should have gone on the valve as it. I can't see any wire connections or where the wires are going What's the gray and orange things ? It looks like some kind of Borg technology for connecting wires...lol
 

rickgburton

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Might be an optical illusion with the picture but are both the flame switch wires connected to the same terminal??
Snapshot_1.jpg
 

ttocsic

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Joined
Jul 11, 2019
Messages
13
Location
New Jersey
I needed to remove the plastic molex connector because it was different than the one on the existing dryer. I had already implemented the Wago connectors when I replaced the igniter last year. I just didn't have the patience to deal with the butt connectors.

The flame sensor actually has three wires going to it. What you're seeing is one terminal that has two wires. The other terminal has only one wire. Better photo tomorrow.

When I get some time I'll try to draw out how everything is connected. Hopefully that will clarify.
 

rickgburton

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Sounds good. That's the first time I've seen that style connector. looks like they work for splicing 3 and 4 wires together.
 

ttocsic

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Jul 11, 2019
Messages
13
Location
New Jersey
These pics should help a bit more.
You can see the three wires connected to the flame sensor. The white wire is the wire that goes to the large wego in the other photo. The black wire also goes to the other bundle of wires. The red wire which is on the same terminal as the white wire, goes up front and disappears under the exhaust vent. Does this make sense?
Another note, since the original orange wire was hard wired to the old coil and the molex connector, I had to splice that lead as well. I know I've kind of made a mess of this.

Do you happen to know where I can find a wiring diagram for this model?
 

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ttocsic

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Jul 11, 2019
Messages
13
Location
New Jersey
I'm pretty sure I'm wired correctly. An initial attempt to start the dryer, tonight led to about 25 seconds of flame then out. Everytime after that was either a short puff of flame or none at all.
I get the sense that either the hold open or the assist coil aren't doing their fair share. I metered them at >1400 and >600 ohms so they can't be bad out of the box, right? One of them still buzzes a little but I can't tell which.
Could the physical plunger in the valve be binding up on something?
 

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rickgburton

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Do you by any chance have the dryer front panel off when you're testing it? The valve could be bad.
 

rickgburton

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What's the third wire for? I can remember seeing that before on GE gas valves but I can't remember what it was for unless it's separate neutral wire just for the hold coil. Your wiring is correct (the best I can tell) so after the flame goes out if the holding coil and secondary coil still have voltage the valve is bad. I've looked everywhere for the wiring diagram. I guess it's just too old.
 

ttocsic

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Messages
13
Location
New Jersey
This model has quite a large inspection door (about 8"x10") so all my testing is with the unit fully assembled. Found this image on the internet. Basically the same model.
Is there an easy way to test the valve? With the coils off, I can pull the plungers up. They move pretty freely and it feels like there's a magnet pulling them back down into place. They also don't just move straight up and down but can "lean" to the sides. Much like a joystick. That normal?
I was also going to attempt to jump the hi limit sensor even though it gives me continuity at room temp.
Could the coils be bad and still meter at the right resistance?
 

ttocsic

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Messages
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Location
New Jersey
The third wire from the flame sensor is a pink wire and it loops under all the plumbing and heads across the front of the unit and under the exhaust vent. Hard to tell where it goes from there.
 

rickgburton

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The image you found is a drawing of a washer??
Is there an easy way to test the valve? With the coils off,
No, or at least not that I'm aware of.
Much like a joystick. That normal?
Probably but I don't know for positive.
I was also going to attempt to jump the hi limit sensor
No need to. If the voltage is still present at the gas valve the problem is on the valve.
Could the coils be bad and still meter at the right resistance?
No, it's just a coil of wire that creates a magnetic field to pull the valve up.
Hard to tell where it goes from there.
You need to find out. Here's why On your diagram the secondary coil is energized when the flame switch opens through the igniter because that's the path of least resistance. Unless whatever that wire goes to has less resistance.
 

ttocsic

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Location
New Jersey
Ok. Getting desperate.
I disconnected the pink wire from the flame sensor entirely. No change in symptoms. Poking my head way in, I think it might go up to the temperature selector on the face panel.

In my desperation, I remove the secondary coil entirely, exposing the plunger shaft. (I know this is incredibly dangerous). I started the cycle and I could feel with my hand, the gas flowing up and out (since the o ring was removed). This tells me that the Hold open and the assist coil are activating and the secondary is not. Metering that coil, I get 675. On the old coil I get 612. Your diagram says it should be 1220. For reference the hold open coil reads 1300 and the assist reads 630. Maybe I do have a bad coil out of the box?
 

ttocsic

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Jul 11, 2019
Messages
13
Location
New Jersey
Today I spoke with a technician from where I purchased the coils. He's sure the valve itself is bad. Now things get interesting. He couldn't find my model number in his system but he gave me the number for GE parts to see if they had it. I called GE and they had me on hold for about 15 minutes looking it up. Turns out, this regulator is no longer manufactured. Unless I can find a small supply house that happens to have one on the shelf, I'm SOL.
I'm wondering if I can use a newer style valve and just figure out how to wire it correctly. Is that feasible? I can't believe I would need to chuck the whole unit just because of one discontinued part.
 

ttocsic

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Messages
13
Location
New Jersey
Right you are. Purchased a new unit today. It gets delivered tomorrow. It kills me because everything else on that dryer still worked so well. Oh well. I wonder if I can sell the brand new coils I just put in.
 
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