Suburban WH won't light

[cobrageek]

There is gas, but it doesn't seem to spark correctly. I hear it clicking, but 98% of the clicks are quieter than I think is correct. Rarely one of the clicks actually sounds like the igniter is really sparking correctly, but it doesn't seem to catch.

I've gone through about 5 or 6 tripple attempt cycles and on the 2nd one it actually made quite a pop at the end of one of the 15 second attempts. I suspect this was a backfire of sorts after 15 seconds of gas was pumped in with only a single spark at the end.

Clearly it is something to do with the ignition system. I suspect that maybe the tips are dirty or coroded or maybe the gap is too large. I could also replace the igniter.

Any suggestions or suspicions as to the problem and solution? Thanks!

[Broadway Joe]

here is the manual for the Suburban water heater.

[cobrageek]

Tanks much joenic53. The service manual is a great thing to have. I was able to find the spec for the gap is 1/8" and I'll check that when I can get time to dig into the thing. I didn't expect to find the service manual up on the web. Very useful.


I also found that the correct igniter/electrode part is only $18 on Amazon so if that needs replacing at least I won't be out much :-). Thanks for the link!

[Broadway Joe]

Glad that I could help.

[Herk7769]

This sounds like a blocked flue. Bugs build nests in there so be careful (they may be wasps).

The gas comes on for a few seconds before the spark to flush out the lines (called a purge cycle). If the flue is blocked (or partially blocked), the mixture becomes over rich and will not ignite.

[cobrageek]

Interesting idea about the bugs. Which part is it exactly you're calling the "flue"? Is that the long tube with the curve in it that has the valves at one end and the electrode at the other? Is it as simple as taking this off and cleaning it out with a pipe cleaner or something?
Thanks for the other idea. I'll see if I can check on that as well.

[cobrageek]

Hmm... looking at the owners manual picture it looks like the "flue" is the sheetmetal box above the burner area. I suppose this controls the amount of air that gets into the combustion area so that would make sense. I'll take that box out and check it for bugs and debris. Could be part fo the problem as well and it looks easy to remove.

[Herk7769]

Compressed air or water is what others have used.

The bronze colored part is the combustion chamber and the flue pipe.

Spray that out real good.

[cobrageek]

Ah, great picture. That helps. I have an air compressor so when I get home I'll blast it out and see if I can get it cleaned out. I'll also remove the electrode(igniter) and make sure it looks good. Then try it out again and see what happens. I'll let you know if I find anything specific or get it working. Thanks!

[cobrageek]

Well Herk, you were right on the money. I grabbed my air compressor hose and blasted out the flue and some bug web/stuff blew out along with a bunch of other cruft. When then went off to our weekend camp for our maiden voyage and it cranked right up. Perfect. Didn't even take out the igniter or anything :-).

Thanks for your advice. It was spot on.

[cobrageek]

OK, I want to remove the "Solved" part of this. It worked for a time or two, and then stopped working again. On our big road trip we had to use 120 the whole time for hot water (nice to have a backup).

I blew out everything again with my air compressor and it still refused to light. I could smell the gas so I knew it was making it somewhere in there and not igniting. I grabbed a BBQ lighter and held it right where the igniter would normall strike and it lit off on the first attempt and seemed to work fine.

So I think there's something wrong with the igniter. I haven't pulled it out to take a look, but I'll do that and check the gap (written as 1/8" in the manual). I'll check the rest of the igniter and probably try replacing it if I see anything suspicious. Any other suggestions?

Thanks. Bret

[ependydad]

I've renamed your thread title. Wish I could help with the water heater...

[OldCoot]

Originally Posted by cobrageek

...So I think there's something wrong with the igniter. I haven't pulled it out to take a look, but I'll do that and check the gap (written as 1/8" in the manual). I'll check the rest of the igniter and probably try replacing it if I see anything suspicious. Any other suggestions?

Thanks. Bret

On our 12Flagstaff8528RKWS, our wh would only light once in a while even when new. I ended up removing the igniter and re-bending the probe. There are more than one dimension it has to meet. Page 12 shows the pictorial of the dimensions. Takes patience to get it, but once I got it bent correctly, it has worked flawlessly ever since.

[Herk7769]

It is possible the spark ignitor got jarred with the compressed air blast of has "crud" jammed in it causing it not to spark. You might have to remove the metal covers and pull the tube to inspect the DSI probe.

[cobrageek]

Thanks OC, Herk. I'll take it apart tonight and see what I can find. It's quite possible that the angle is just not quite right and that the ignition just isn't working due to that.

[cobrageek]

OldCoot was right on target. With the picture from the manual in hand I compared the location of the igniter probe and it was almost completely centered in front of the burner. Rather than bend the probes I actually bent the mounting bracket just slightly as the 90 degree bend in it was closer to 95 degrees. When I made it around 88 degrees the probes landed at exactly the spot shown in the manual.

It lit right off after about 3 clicks after the fix. So it must've been so much in the blast of the gas that it was blowing out immediately. Another fix chocked up to the experence of the forum. Thanks much for your help!

[OldCoot]

Originally Posted by cobrageek

... Thanks much for your help!

Glad to have been of a little assistance. That's why most of us are on the forum to help others.

[abanks]

I absolutely love the forum. I am having the exact same issue with my 2012 27HFS. The first thing I did was check the forum and found this thread. Thanks for giving me a really good place to start.