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charlyhors

Water heater won't light/ stay lit

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My 10 gallon gas electric water heater (Atwood 10-E) has trouble igniting and also trouble staying lit.  It's an intermittent problem, but mostly doesn't light and then only stays lit for a few mnutes when it does lite.  I adjusted the air mix to where there is a nice clean smooth blue flame when it's working.  (still goes out after a few minutes) I've cleaned out the curved tube that funnels the gas to the larger burner tube.  I've adjusted the electric igniter and ground to the correct 1/8" gap.  

I've played with the position of the igniter assembly.  There is a dime sized piece of metal mounted an inch or so in front of the gas pipe going into the burner.  I assume that is to spread the gas flow more evenly down the burner tube.  I've adjusted the position of the igniter assembly both directly in the center of the burner tube, and also off to the side, with no great luck either way.

Any ideas on diagnosis or repair?

https://photos.app.goo.gl/6kLQ394OBDDGweHF2

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The first thing that comes to mind is the spark rod. The same rod is used to determine if there is a flame. If it is dirty  (it may look fine to the naked eye) it won't be able to pass the electricity required to keepthe flame going. Pull the rod and polish it with some steel wool and see what happens.

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Charly, good question, I've been there done that n got the T Shirt when I was a used RV dealer lol

 Here are URL links to an owners and a service manual with Troubleshooting Tips which are probably better then what I or perhaps others have to say, check them out for the ideas you asked for:

 

http://www.atwoodmobile.com/manuals/waterheaters/MPD%2093756%20SP%2011.19.07.pdf

 http://manuals.adventurerv.net/Atwood-Water-Heater-Service.pdf

 

 

Having troubled BOTH igniting,,,,,,,,, and trouble staying lit (flame sense isn't staying activated) makes me think it could possibly be an ignitor tip problem such as location or gap or a fault such as a hairline crack or a carbon trace or some short of an electrical shunt path etc. or a loose/resistive/corroded (voltage dropping) connection or ground

I had an Atwood that acted similar and a simple slight relocation of the ignitor tip cured it (for a while at least). One problematic location was cured by only a 1/16 inch adjustment. Another problem was when the gap was set too close. On another the relocation cured it for some time, but it reared its ugly head later in which case a whole new ignitor tip assembly with the attached HV cable and proper gap and location fixed it permanently. If the board and HV coil/transformer all check out okay and the connections  are good and it has a good ground and you narrow it down to an ignitor tip problem, they are relatively cheap as an assembly on Amazon or Flea Bay. RV dealers may have a circuit board tester if you can get then to test yours.

Of course, if the T stat is faulty it may be shutting off power killing the flame even if all else is fine??? Similar if the circuit opens due to a limit or overheat switch power is again lost shutting it down.  

Simple no cost measures like cleaning up all the connections and grounds and voltage tests if its low and insuring the boards HV coil/transformer itself is producing a HV spark independent of any HV cable and ignitor tip and insuring its NOT a T stat or limit switch problem (temporary by pass them) may help. I have had luck simply removing the cable connector off a control board and cleaning the contacts.

I also like Toms tips above of simply cleaning the ignitor tip

Sorry you asked for "ideas" and those a the first few that came to mind, connections,,,,,,,, and ignitor tips,,,,,,,,,,,, and low voltage,,,,,,,,,,,, and input power problems,,,,,,,,,,,,or T stat or limit switches,,,,,,,,,,,,,,,,,, so download the manuals and run thru their troubleshooting tips and let us know what you find.

If the ignitor tip is having difficulty lighting the flame it may well also have problems keeping a sufficient flame sense signal to keep it lit?????????????

 

John T  NOT any heater expert so do as the experts and/or the manual says NOT MEEEEEEEEEEEEE        

 

 

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17 hours ago, markandkim said:

You will need a new circuit board. Been through the same issue. Amazon has them.

If he does end up needing a new board (could be if its not another problem), I have good luck with those made by Dinosaur Electronics...

 

John T

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5 minutes ago, oldjohnt said:

If he does end up needing a new board (could be if its not another problem), I have good luck with those made by Dinosaur Electronics...

 

John T

I'll second the 'recommendation' for Dinosaur boards .  I've replaced the furnace and fridge boards with Dinosaur brand and haven't had a problem since .

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I just went through a similar issue over the past few months. This thread has a lot of info and tips. I'm pretty sure my problem ended up being low voltage to the board due to a bad converter and undercharged batteries.

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10 hours ago, Tcwndsr said:

This thread has a lot of info and tips. I'm pretty sure my problem ended up being low voltage to the board due to a bad converter and undercharged batteries

 I used to think low voltage to the circuit board shouldn't prevent a furnace or water heater from working especially if there was still enough voltage to spin the fan    WRONG     as I found out the time I talked to Dinosaur Electronics who lectured me as I shared on here before. CONNECTIONS CONNECTIONS CONNECTIONS...

 

 John T  

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 On Atwood water heaters that have a small spark wire for ignition and sense, see if there is a little black smudge where the wire touches the door cover when it is closed.

 

 I have fixed a few that the wire would short out to the door. Just bend the wire so it will not touch the cover when closed. The wire looks good but sometimes it will show a black Mary on the cover.

 

 Just possible,.  Vern

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I cleaned the sparker, all the wire connections, then replace the sparker.  Still isn't lighting.  It Does make the Click Click sound and gas does come on, but I sure can't see a spark.  Should you be able to see the spark?  Does the click sound indicate that it IS sparking?  The click sound was there with both the old and new sparker.  (It does fine if I hand light it each time.  And it also works on park electric

 

Edited by charlyhors

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The clicking sound is the spark. It may be sparking to ground someplace else. Do it in the dark and you should be able to see a nice fat spark, someplace. If it isn’t where it is supposed to be, the wire may be bad. You will need to check all the way to the board. 

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"The clicking sound is the spark. It may be sparking to ground someplace else. Do it in the dark and you should be able to see a nice fat spark, someplace. If it isn’t where it is supposed to be, the wire may be bad. You will need to check all the way to the board. "

I checked it in the dark.  There is No spark anywhere, even with though it makes the clicking sound.   ???  I'm about ready to buy a new circuit board.

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17 hours ago, charlyhors said:

I cleaned the sparker, all the wire connections, then replace the sparker.  Still isn't lighting.  It Does make the Click Click sound and gas does come on, but I sure can't see a spark.  Should you be able to see the spark?  Does the click sound indicate that it IS sparking? 

 Good observations good info hmmmmmmmmmm lets see lol

I describe the sound of the HV arcing/sparking as tic tic tic tic tic and the initial sound of the gas solenoid valve opening as one loud sharp CLUNK You can feel it also) .

 If the rest of the system is working when the t stat calls for heat power is sent to the board and the gas valve opens and the boards circular HV coil/transformer starts emitting short term HV pulses which get to the ignitor tip then ground via that short piece of (maybe red or orange)  thin HV cable.

 YES in the dark you should see the small sparks each tic tic tic tic from the ignitor tips end to ground !!!!!!!!! If you HEAR but don't SEE the sparks at the heater, the HV cable may be bad/shorting or on the boards HV coil/transformer the HV is leaking to ground (each tic) and NOT getting to the Ignitor tip and cable. If the gas valve is opening and the boards HV coil/transformer is producing the HV pulses the board could possibly be okay BUT THERES A SHORT IN THE HV CABLE,,,,,,,,,,,,, OR THE IGNITOR TIP IS BAD,,,,,,,,,,,,,,OR THE BOARD (or its HV coil)  IS BAD IN THAT HV IS PRODUCED BUT ITS GETTING SHORTED AND NOTTTTTTTT GETTING TO THE HV CABLE AND IGNITOR TIP !!!!!!!!!

 Look at the board in the dark and when you hear tic tic tic see if its sparking on the board or coil somewhere (its bad) and NOT out at the ignitor tip to light the gas

Tic tic tic is HV spark but a bad board or bad boards HV coil or a board short or a bad HV cable or a bad ignitor may be jumping the spark elsewhere NOT at the ignitor tip to ground

If its a new sparker/ignitor tip gapped correct to ground  and a new HV cable and its ticing  and sparking ELSEWHERE, the board (including its HV coil) may well be the problem!!!!!!!!!!!

NOTE it may still be producing a HV pulse and a spark and you hear the tic tic tic BUT STILL NOT SEE IT because its shorting internally or behind the board or elsewhere STILL INDICATES A BAD BOARD GRRRRRRRRRRRRRR

I use a small jumper wire from the boards HV coil (I remove the HV cable to ignitor) to 1/8 to ground and see if it sparks when the board operates??????? If so but NOT at the ignitor tip I suspect a bad ignitor tip or bad HV cable or improper gap or a short BUT if its arcing on the board somewhere (0r NOT producing HV pulses at all) ,,,,,,,,, sounds like a bad board IF SO CHECK DINOSAUR ELECTRONICS FOR A REPLACEMENT

    

John T

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On 11/18/2017 at 11:47 PM, charlyhors said:

I checked it in the dark.  There is No spark anywhere, even with though it makes the clicking sound.   ???  I'm about ready to buy a new circuit board.

One very common failure of the spark probes is the ceramic insulator that encases the high voltage probe will develop a very fine crack. Once that crack fills with carbon from the burning gas it then shorts the high voltage to ground and even though you can still hear the tick sound, there is no spark. Because the spark probe is relatively inexpensive and easily installed, I always try replacing it first. 

There is a very easy way to determine for sure that you are getting propane from the valve.  If you have one of those long, butane lighters like we use to light a barbeque you can light it and hold the flame in the area next to the ignitor probe while an assistant turns the water heater on. If you really have propane it will light at least briefly. The same probe that supplies the spark to light the flame also returns a small signal to the circuit board that tells it the flame is burning. It is quite possible that your probe is not returning that signal. When that happens the propane will light but the spark continues to try for 3 attempts and then because it didn't detect the heat the circuit board will turn off the propane for safety. That return signal is in the micro-volt range and you can't detect it with a meter.

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 Hey Kirk,.  I have test for you to try. 

 

 First get a good spark plug. Then a propane torch. Just a simple one as for soldering. And a DC meter set on milivolts.

 Now hook one lead of the meter to the center post of the plug. The other on the metal outside threaded part of the plug.

 Now light the torch and put the flame over the spark end of the spark plug. Make sure the flame is covering the end and see what you meter reads on DC milivolts.

 

 Just for fun ,.   Vern

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All the comments have been helpful and interesting as usual.  Thank you all.  I got on the phone with Dometic/Atwood, to find the new part # for my circuit board and ask about warranty - our RV is only 15 months old.  They were nice enough to promise to ship one directly to me.  Which is wonderful.

Reading reviews of that board on Amazon - Atwood item 91365 - looks like a pretty iffy item- averaging 3 stars.  I would order from Dinosaur, except for the possible freebie working.  Also I didn't see a part there that looked like this board.  If the Dometic board fails, I'll use Dinosaur's customer service email to find their replacement part

I'll update this with how things come out, when I receive the board and install.

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4 hours ago, charlyhors said:

They were nice enough to promise to ship one directly to me.  Which is wonderful.

GREAT,,,,,,,, Free is good,,,,,,,,,,,,  When shopping at Dinosaur I also at times didn't find their picture matched my old board perfectly, but they assured me it would work which it did. So you indicated above you have a new "sparker" hopefully that and a new board will get you going:

Thanks for the feedback

John T 

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15 hours ago, charlyhors said:

Also I didn't see a part there that looked like this board.  If the Dometic board fails, I'll use Dinosaur's customer service email to find their replacement part

The Dinosaur boards are direct replacements but are sometimes configured somewhat differently from the OEM. When I changed the board in our Atwood water heater in the previous RV to one from Dinosaur, I did have to use the mounting bracket from Dinosaur because of a different configuration. 

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All the comments have been helpful and interesting as usual.  Thank you all.  I got on the phone with Dometic/Atwood, to find the new part # for my circuit board and ask about warranty - our RV is only 15 months old.  They were nice enough to promise to ship one directly to me.  Which is wonderful.

Reading reviews of that board on Amazon - Atwood item 91365 - looks like a pretty iffy item- averaging 3 stars.  I would order from Dinosaur, except for the possible freebie working.  Also I didn't see a part there that looked like this board.  If the Dometic board fails, I'll use Dinosaur's customer service email to find their replacement part

I'll update this with how things come out, when I receive the board and install.

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Well, Dometic shipped the new motherboard under warranty.  Popped it in.  Immediate strong lighting.  So I guess those that said it was the board were correct.  And those that said check the connections and the sparker were also correct as it could easily have been that.  And the shop manual and a sticker on the heater also said to check all connections and clean them before replacing the mother board.  The new board did have a bigger coil, and I think that probably helps generate a stronger spark.  

Once again, the Escapees forum helped me solve a problem, and the water heater is no longer such a mystery to me.  :-)

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1 hour ago, charlyhors said:

 

Once again, the Escapees forum helped me solve a problem, and the water heater is no longer such a mystery to me.  :-)

CONGRATULATIONS and thanks for the update and feedback. Indeed if it wasn't the "sparker"/ ignitor, or a connection or voltage problem (easy CHEAP things I always try first) it was the more expensive grrrrrrrrrrrrrr circuit board lol MURPHYS LAW PREVAILS. I've also had to buy those boards myself when all else failed........... 

 John T

Edited by oldjohnt

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