Fixed camper water heater that continued to spark after lighting....

The problem:

Our water heater an Atwood G6A7P, basically a manual water heater with an electronic "match" to light pilot. -after lighting the pilot the electrode continued to spark. I would turn off the electronic spark module, because it would just continuously spark forever.

    Note-after posting on the forum, venting my frustration with this problem and its fix, decided to put the info here BECAUSE as explained, I could not find anywhere a description or fix for what my water heater was doing. Even the local RV shop suggested replacing the auto relight module ($60-100). There are many things that can cause your heater to not operate, but this is another-with a simple fix. Hopefully this might at least offer someone else the possible option to fix without unnecessarily spending monies.

    It was thru several posts-as I was making changes-visits to the parts house that the cause and accidental fix became clear. It was the knowledge of some others that made it clear how heater ignitor works, & why it now works.

The process:

    Identify the cause and possible course of action.

    I spent at least 4hrs searching online with no luck. I know more about my heater & and all its variations than I could have imagined. But nothing even close to what ours is doing. I have an Atwood 6gal water heater G6A7P with auto relight, with Apparently a unique problem.

    It works great, lights 1st try, temp is perfect, relights if wind blows out pilot, plenty of hot water for our usage. However quite a few months back walking by heater I heard the auto relighter sparking. Assumed pilot blew out, lil later I noted it was still sparking. Opened the door, pilot is lit? blew out pilot & it relit. Turned up temp heater fired up. turned temp back down, auto relight is still going. blew out pilot again it relights. I'll add once pilot lights the spark only fires off bout every 3seconds instead of the virtual constant when pilot out.

    When I got home brief look (dinosaur) new module in$100 range, hmm. So last few trips once lit I turn off reignitor module.

    Well with more time finally decided to look again. Most problems, even Atwood states in manuals can be traced to dirty/bad connections. With no other options besides throwing money, pulled everything. removed the ignitor Module & electrode, removed pilot thermocouple tubes, all the odd bits of sheet metal, burner etc. , cleaned everything, I I did have quite a bit of rust corrosion. Cleaned out flue, drained the tank while everything was out.

    Reassembled my like new heater - nada. once pilot lights, spark module goes to slow spark indefinitely. like it knows it lit, but keeps checking. I was thinking maybe the electrode sends a signal back to module, can't figure out how it knows pilot is lit. Took to local shop. Said it was fine, probably the module keeping it from lighting. I told him it was sparking, lighting the heater, the heater works fine, it just continues to spark. he says "no when they quit they'll stop sparking??? I can order you a module." Errr thanks maybe later. Home I went.

    Well even though I found new module for under $60 I just put everything back together, deal with it when it stops working.

    guess what- it's working! Why I have no idea. pilot lights, spark stops. Took off the electrode, wiring module, checked gaps.,placement, fiddled with wires connections, all but tried to make it repeat previous puzzle. Works now exactly like it should. Why?

    After some more queries some responses from others who are familiar with different systems. Here are the more knowledgeable folks responses-even so took me a while to grasp it. Looking back I can hear what they were trying to say but at the time just over my head.

      [ Rvpapa
      The ignitor has to be in the pilot flame to work properly. The board senses the conductivity of the flame and should shut down the spark.]

      [ azpete
      the flame sensor actually reacts to the ions within the flame to complete a ground and send a signal to the module. the metal probe on the sensor builds up a coating when exposed to the flame for extended periods which increases the ohms, which indicates a lesser ground than is needed to hold the valve open. sand the probe down to shiny metal and try it. this helps most of the time. this was a atwood engineers explanation to me. ]

      [ FoCoNoCo
      Most residential and commercial furnaces utilize the same system of flame sense. The control module sends out a small electrical charge through the ground side of the equipment, which is carried through the ionization of the flame and the circuit is completed through the flame sensor back to the module. This electrical charge is generally a 2.0-6.0 microamp DC charge.]

    My "accidental" fix that I hadn't realized until the above explanations explained it and how this simple system works.
    When after initial reassembly it didn't work I took electrode to parts house. My thought was to replace electrode. There cheap & i was thinking it might some how not be signaling module.- which had they had one in stock, replacement would have worked. However, he didn't so I reinstalled it. But more importantly it also explains when I reinstalled why, as noted above, it worked.

    Looking more closely (magnifier) I noted it wasn't 'clean' and used 400grit to clean before reinstalling. Didn't even register.

    Eureka! That and the flame is part of the circuit-amazing. I had come to this conclusion by elimination but rejected it. The idea that the flame was a conductive part of circuit was beyond my grasp and couldn't accept it.

So the conclusion:

    If your ignitor continues to spark after the pilot is lit, before buying parts, try cleaning. Carefully remove (cold) ceramic encased ignitor electrode by removing the screws attaching it to pilot assembly.
    Note the ceramic part is quite fragile, but luckily inexpensive ($15)
    Carefully clean the exposed metal end of electrode. I used some 400 grit wet/dry paper.
    I would also recommend since your in there to remove all screws holding the pilot assembly, the ground wires and clean, insuring a good ground path.

    If cleaning doesn't work I'd try replacing electrode 1st #93804, then the module #93801 as a last resort, assuming you cleaned everything in the ground path.

    My opinion also is that if your is NOT sparking, though less likley it could also be a matter of cleaning. The module can be taken to an RV shop, most have the ability to test. The electrode if the ceramic insulator cracks will ground and not spark.

    Mark..apparently not as smart as a potted 3" ignitor module

    Update 7/2016...5 years later. Water heater 'sparking' again. No matter how much I cleaned would restore normal function. Also stock parts no longer available. Adapted simple Suburban ignitor/relighter kit to replace. Newer style Atwood parts may work but no cross over part numbers/direct replacement recommendations- considerably higher cost...

    I would recommend seriously cleaning electrode- all paths/ connections in wiring. Second replacing electrode, last the module. However if electrode doesn't fix and need unavailable module, at that point kit that includes electrode and module is more cost effective. See Water heater ignitor replacement page

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