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Water Heater won't ignite


Frank and Pat

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We have an Atwood water heater in a 1996 Winnebago. 6 gallon gas, electronic ignition. When outside temp is 64 or higher, the pilot will not ignite. I called Atwood, never heard of this problem. Had Camping World and an independent service/repair look at it - cleaned it, put camera into flue - all say outside temp has no bearing. But as soon as it is 63 outside, the pilot will light and stay lit. Any ideas?

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Sounds like maybe things need a good cleaning and the igniter moved a tad closer , so the spark has less distance to jump .

 

Everything expands and contracts with temperature variations . Some more noticeably than others , but ...

 

We had a similar problem . I cleaned the gas orifice and both the igniter and the surface it jumped to . Slightly bent the igniter a bit closer . Problem solved .

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We have an Atwood water heater in a 1996 Winnebago. 6 gallon gas, electronic ignition. When outside temp is 64 or higher, the pilot will not ignite. I called Atwood, never heard of this problem. Had Camping World and an independent service/repair look at it - cleaned it, put camera into flue - all say outside temp has no bearing. But as soon as it is 63 outside, the pilot will light and stay lit. Any ideas?

 

 

You say it has electronic ignition AND a pilot light? Mmmmmmmmm. Is something wrong with this picture?

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We have an Atwood water heater in a 1996 Winnebago. 6 gallon gas, electronic ignition. When outside temp is 64 or higher, the pilot will not ignite.

Do you have one of the pilot light models that does not have electronic direct spark igniting of the flame that heats the water? Are you dealing with the version that has a button to hold down while lighting a pilot and which must be held until the pilot will remain burning, as by 1996 most RV builders were installing the direct spark type of water heaters that have no pilot.

 

If you have the direct spark model I would replace the spark probe as it may be that yours has a cracked ceramic insulator an when temperatures are warm it shorts out the electricity to make the spark. I have seen a cracked ceramic insulator cause intermittent failure to light.

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Frank, its been my experience (Atwood or Suburban) the distance between the ignitor tip (assuming its elec ignition as you stated????) and the burner is fairly critical, maybe 1/8 or so, consult your manual. I recently had a problem where it was necessary to adjust the ignitor tip to burner location which cured a no lighting condition. However I later had to replace the ignitor tip even though there were no visible to the eye cracks or carbon traces. If it fails to light (assuming what you stated elec ignition) I place a jumper wire on the (if so equipped) control boards HV ignitor output to within 1/8 of metal and see if I get a HV spark there??? If so there but NOT via the ignitor, I suspect a bad ignitor or bad HV cable to it or its incorrectly located/spaced. I've seen several control/ignitor boards go bad (no HV ignitor spark output) which I usually replace with a Dinosaur Electronics unit. Ive also cure some problems (some makes and models not all) by removing the flat ribbon connector to the control board and cleaning the boards flat contacts then she worked fine. Is the gas valve opening ?? you can hear its faint click and/or feel it.

 

John T

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I recently had a problem where it was necessary to adjust the ignitor tip to burner location which cured a no lighting condition. However I later had to replace the ignitor tip even though there were no visible to the eye cracks or carbon traces. If it fails to light (assuming what you stated elec ignition) I place a jumper wire on the (if so equipped) control boards HV ignitor output to within 1/8 of metal and see if I get a HV spark there???

The spacing or gap for either Atwood or Suburban is 1/4", +/- 1/8". Anything under 1/8" the spark is so small that it may not ignite the propane.

 

It has been my experience that when problems start with the ignition probe, cleaning and adjusting will usually help for a while, but it is seldom more than temporary so if I do that I also pick up a new one at the earliest convenience to have on hand when the problem returns. It takes very little time or expertise to replace a probe and the cost is typically about $30 - $40.

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I bought the ignitor tip I spoke of above with HV cable for around twenty bucks, as I said check manual for proper ignitor tip gap (my Suburban called for 1/8" + - 1/32" ignitor gap and if so equipped 1/4" for a flame sensor) and if the control boards HV ignitor throws a good spark and the gas valve opens ?????? but still no ignition, its time to try checking, cleaning, and adjusting the ignitor tip, but do as I did and have a spare handy lol.... Let us know what you find (control board, ignitor tip, gas valve operation, low or no voltage, other SIMPLE fixes etc)

 

John T

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  • 2 weeks later...

My Atwood 10 gallon direct spark water heater is having trouble lighting. It starts up but immediately goes out, repeats for 2 more times then locks out. I've cleaned all the contacts and tube, igniter elements and anything else I could get to. I couldn't get the flame to stay lit until I whacked the gas valve several times. I'm suspecting the gas valve is having some solenoid valve issues. Is this valve rebuildable, or must it be replaced (mucho $$$)?

 

Ken S - Wobblywheels

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Ken, the gas valves are not rebuildable.You will have to replace it. If the burner flame was strong then it seems as the valve was opening properly and the problem lies elsewhere. Most of the time if the burner lights and goes out it is because of a safety shut off doing what it is supposed to do if the control thinks there is no flame. Try cleaning the spark rod with steel wool and if there is another rod and wire close to it clean that rod too. Make sure that the spark rod is about 1/8 inch to 3/16 inch from the burner tube. If that all checks out you may have a control issue that needs addressed.

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First, welcome to the Escapee forums! We are sorry that it took a problem to bring you here, but happy that you came. :)

My Atwood 10 gallon direct spark water heater is having trouble lighting. It starts up but immediately goes out, repeats for 2 more times then locks out. I've cleaned all the contacts and tube, igniter elements and anything else I could get to. I couldn't get the flame to stay lit until I whacked the gas valve several times. I'm suspecting the gas valve is having some solenoid valve issues. Is this valve rebuildable, or must it be replaced (mucho $$$)?

Like Mntom, I highly doubt that your problem is the propane supply valve, because in all of my years of RV experience, I can only recall one time that one failed, but I have heard of it a few times. If the valve is bad it is probably an open coil and that can be easily checked with an ohm meter. Mechanical failure is also possible, but difficult to check. If the propane lights at all, that seems to indicate that the valve has opened. If the gas is burning but the spark continues to fire for three times, then turns off the gas and goes to lock-out, that indicates that the heat sensing didn't happen. On your spark probe the same electrode that provides the spark also is a heat sensor to detect the burning propane. It sends a tiny voltage (micro volts) back to the circuit board that tells it the flame is burning and that then stops the spark and holds the gas valve open. If it does not sense heat after the third attempt, the power is removed from the propane supply valve's coil, the valve closes and it goes into lock-out. By far the most common cause of this problem is a failure of the heat sensing ability of that probe and while cleaning might help for a time, if it doesn't help that still don't eliminate it as the problem since the return voltage is nearly impossible to verify. I would first replace the probe assembly since those will cost about $30/40 and it can be easily replaced. The spark gap should be 1/4", +/- 1/8".

 

It is also possible that the circuit board is failing to recognize the return signal from the probe and that too is difficult to prove except by trying a new circuit board, which is what most RV shops do. The return voltage from the probe gets back to the circuit board by way of that same high voltage lead so make sure that the connection between it and the circuit board is clean and free of any extra resistance. I have seen a poor connection there cause your symptom many times and a quick check of that is to clean it carefully and reseat the spade connector several times to clean it. That connection needs to be as near to 0 Ʊ as you can get it.

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The gas solenoid valve is pretty simple. If you listen and have your hand on it you can both feel and hear it open. First of all if voltage is applied it should activate and open and a test light should light up when its activated. If its coil is open (valve is bad and inoperative) it would read high or infinite ohms. Usually if it opens but the flame fails to ignite you smell a whiff of propane out the exhaust.

 

If the t stat calls for heat and the blower starts and the sail switch makes up after a delay the gas valve should open and high voltage is sent from the ignitor board to the ignitor tip and you may hear the snap snap snap of a HV arc to the burner to ignite the gas. I cant recall if I ever had a gas valve go bad (when a used RV dealer plus user) but more often its the circuit board or else the ceramic HV ignitor tip that's the cause of no ignition. Its easy and not rocket science to use a jumper wire to see if the circuit or ignitor boards HV transformer is throwing a HV spark and if not the board may be bad but if so, then its often the ignitor tip is bad or has a hairline crack or a carbon shorting trace. My suburban calls for a 1/8 +/- 1/32 gap from ignitor tip to the burner and that's fairly critical but check your manual for its proper gap. My last one stopped firing but did after I cleaned and adjusted the tips gap but quit again so I replaced it now all is fine.

 

John T

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