Ongoing saga with Suburban water heater

[jrminiquad]

I am having an issue with my Suburban SW6 DE water heater. This is an electric/propane model.

It stopped working on propane late last year, but still works fine on electric. I did my research through the forums here and first thing that came to mind was the run of faulty circuit boards they had. I pulled mine and although it did not look to have any bad or burnt resistors, I sent it in to Suburban over the winter and they replaced it under warranty.

New board made no difference. I still get the three times trying to light with no luck, and then the DSI fault light stays on.

Here's the facts:
- have propane, furnace, stove and burners have all been working fine
- water heater works on electric
- I cleaned out the burner tube and it is not clogged up with anything
- I am getting flame at the beginning of the tube, a short burst of flame into the "hot box" when it tries to ignite, and I can see the spark igniter working

I am at a loss of what to try or check next. Any ideas?

[B and B]

Spider nest in the gas orfice or the burner tube. Have a close look at both. Maybe a wasp made a nest.

Also check the rubber buttons, both sides should be pressed in to reset high temp limits.

[jeff64]

I had similar last year with mine. Mine would make a big bang which after the 3-4 x I made the connection. ...an yes the burner tube was clean. You could hear/see the spark. What I did was pull the igniter and clean it with a brass brush as well as the ground electrode and especially the mounting of the electrode assy to the burner. It was showing some signs of rust/corrosion. In the suburban service manual(google for .pdf) it will give you some alignment specs. In my case, I didn't change the positioning of the electrode. But, in most cases the ground integrity has a great influence since a flame presence/ feedback is sent to the board. You can always blow out the burner chamber while you are at it. I've been good to go on this process here or just lucky!I had the same symptoms you described.

[Kaadk]

What you're describing sounds like it's lighting, but the board doesn't know it lit, so it's shutting off the gas. So, it sounds like the flame sensor might be misaligned or faulty.

[HangDiver]

Following...

[Scrapper]

Originally Posted by B and B

Spider nest in the gas orfice or the burner tube. Have a close look at both. Maybe a wasp made a nest.

Also check the rubber buttons, both sides should be pressed in to reset high temp limits.

X2
A little dirt or soot on the orifice will cause those kinds of problems. Heck, even a drop of water will do the same.

It seems like I am sending this document to other owners of Suburban WH at least once a week even though it is in the Library section in the green bar at the top of the page, look under Forest River Forums > Downloads > Plumbing, Propane and Water Systems > WH_Service and Training Manual 05-18-11.pdf. It is a download so you can save it to your computer's hard drive for future reference. If you are using a tablet, save it to a USB thumb drive, you may even do this with your smart phone.

If you can't find it, click the link below.
Forest River Forums - Downloads - WH_Service and Training Manual 05-18-11.pdf

[Awilson]

Originally Posted by Kaadk

What you're describing sounds like it's lighting, but the board doesn't know it lit, so it's shutting off the gas. So, it sounds like the flame sensor might be misaligned or faulty.

I agree. There is a proof of flame sensor that tells the circuit board to keep the valve open to deliver fuel to the burner. It is a safety so that your burner does not fill with unborn fuel and you spark ignites it. The sensor MUST be placed in the flame or it will never know there is a flame. Good call.

[PumaCC21]

We had the same problem with our new Camper after 2 weeks. The problem was the board fixed on the water tank with double face tape, not good with electronics board. We now have a new one. Good luck

[jrminiquad]

Thanks to all for your quick replies. As a follow up, prior to my posting I did check both reset buttons a few times and both are depressed.

Additionally, I had blown out the burn chamber and burn tube with compressed air, and although there definitely is some rust/corrosion, it looks fairly clean.

I will get a chance in the next couple of days to take it apart again and take a wire brush to try and clean it up some.
I have downloaded a couple of manuals for it.

The only thing I am still lost on now is where exactly is the flame sensor? Nothing in the parts list in the manual is calling out a sensor. Are they possibly calling it something else?

[5picker]

Originally Posted by jrminiquad

Thanks to all for your quick replies. As a follow up, prior to my posting I did check both reset buttons a few times and both are depressed.

Additionally, I had blown out the burn chamber and burn tube with compressed air, and although there definitely is some rust/corrosion, it looks fairly clean.

I will get a chance in the next couple of days to take it apart again and take a wire brush to try and clean it up some.
I have downloaded a couple of manuals for it.

The only thing I am still lost on now is where exactly is the flame sensor? Nothing in the parts list in the manual is calling out a sensor. Are they possibly calling it something else?

The flame sensor and the DSI spark electrode are one in the same.
It creates a spark to light the flame and when the probe gets hot (from the flame) it sends a signal to the board to prove the flame has lit.

[jrminiquad]

Gotcha.

Any idea where in the flame this should be positioned? Doesn't seem to say anywhere in the manual.

[Danesville]

The sensor tip should be about 1/8 inch in the flame to pick up a good signal, they do wear out so it’s always nice to keep a spare

[KyDan]

Google "flame rectification".

Here's a simple cut and paste--
Flame rectification is a method of flame sensing in modern gas furnaces where the flame sensor (flame rod or ignitor) is located in the pilot or burner flame and a current applied to the sensor flows through the flame to the pilot assembly or the burner head and then to ground.

When the flame ignites the hot plasma of the flame itself will allow the "flame sensor" to pass a tiny amount of current through the flame. IF THE BOARD IS GOOD it will see the tiny current and all is well.
If the board does not sense the tiny current passing through the flame it will fault out and shut down.

Don't rule out a bad board even tho you got another one from the factory. A bad flame sensor board won't show any burned components visible to the naked eye.

The flame sensor MUST be well into the flame and occasionally just polishing it with fine sand paper will make the difference.

Good luck!!

[FleckDreher]

Originally Posted by KyDan

Google "flame rectification".

Here's a simple cut and paste--
Flame rectification is a method of flame sensing in modern gas furnaces where the flame sensor (flame rod or ignitor) is located in the pilot or burner flame and a current applied to the sensor flows through the flame to the pilot assembly or the burner head and then to ground.

When the flame ignites the hot plasma of the flame itself will allow the "flame sensor" to pass a tiny amount of current through the flame. IF THE BOARD IS GOOD it will see the tiny current and all is well.
If the board does not sense the tiny current passing through the flame it will fault out and shut down.

Don't rule out a bad board even tho you got another one from the factory. A bad flame sensor board won't show any burned components visible to the naked eye.

The flame sensor MUST be well into the flame and occasionally just polishing it with fine sand paper will make the difference.

Good luck!!

X2
Flame sensor is just an electrode in the flame.
They get dirty, corroded, or out of position.
Another possibility is a dirty gas orifice which will decrease the flame size and change its position.
DO NOT clean it with any metal tool, use a toothpick in a rotary motion.

[Iwannacamp]

I will ask...in case I missed it. Is it sparking? If so. The board is good.
There are stories of voltage loss/leaking...maybe it's not getting to the igniter. Mine had issues and the connector(silicone insulator) was kinda hard to get on. Make sure it is connected well.
My board failed on the first trip(after PDI) and Suburban sent me a new board. If I were buying one I would opt for a Dinosaur Brand. YMMV

Here is the dude I talked to...

Please contact our Tech support group to discuss operational issue. Phone number is 423 775-2131 extension 7102. Have model/serial number of the appliance when calling.



Ronnie Ellison

Service Manager

Airxcel,- Suburban Division

676 Broadway Street

Dayton,TN 37321

Office: 423 775-2131 Extension 7007

Fax: 423 775-7015

Airxcel | AC, Heating & Appliances for Industrial and Personal Use

[Iwannacamp]

I will prolly get sparks for this....

Take an item as... 1/4 x 6" or #2 x 6" screw driver and PECK on the steel line that feeds the burner... If there is something in there it MIGHT knock it out. Cheap check

[nomad297]

It sounds like a bad gas control valve to me if everything is good with the orifice.

Bruce

[jrminiquad]

I wanted to thank everyone again for your input and help. Not exactly sure which one that did it, but I cleaned out the tube again, tried the ole "toothpick trick", tapped on the gas line, removed and sanded the igniter/sensor, reassembled and now have a working hot water heater on propane.

[Awilson]

Originally Posted by jrminiquad

I wanted to thank everyone again for your input and help. Not exactly sure which one that did it, but I cleaned out the tube again, tried the ole "toothpick trick", tapped on the gas line, removed and sanded the igniter/sensor, reassembled and now have a working hot water heater on propane.

That is so awesome to have it fixed and knowing you fixed yourself with the help from people on this forum.

[Bama Rambler]

I'm truly glad that you got it working and came back and let us know what you did, even if it was several things.

I learned many years ago, when troubleshooting issues to do one thing at a time. that way you have a pretty good idea what fixed it. It takes a little longer sometimes to get to the problem, but me being the person that want's to know exactly what was wrong has learned to live with it.