Suburban SW6DE will not stay lit after ignitor stops sparking

[ericrobertlarson]

Hey everyone,

I have been trying to troubleshoot my Suburban SW6DE water heater for a while. The electric element works fine, but we cannot really use it because 1) many of the campgrounds we use do not have hookups. And 2) it does not really keep up with the needs of 7 people.

Symptom:
After I turn on the unit it attempts to light. We do get gas and the unit fires immediately with a nice solid blue flame...as long as the igniter is sparking. As soon as it stops then the flame goes out.


Research:
I have been reading up on this issue and have done the following:

1. Replaced the Electrode/Igniter unit (part #232258). This did not bring about any change at all.

2. Cleaned the burn tube and orifice. there was nothing in it, and this did not change anything about our situation.

3. Changed the gas outlet manifold (mine was twisted, as it turned out, cracked). This was necessary, but did not change anything in the end.

4. Checked continuity for the electrode and the resistance on the gas valve solenoids. Everything seems good here. I did not expect a problem with the solenoids because it is firing, and quite well.

This seems to leave the ignition control board, which I have ordered. However I am skeptical because most people who replace them can see a place where they have shorted out or burned. I cannot see anything like this on mine.

For those who might know do you think that the control board sounds right or should I look elsewhere for my problem?

Thanks,
Eric

[nomad297]

Bend the igniter/flame sensor more into the flame and closer to the ground probe on the igniter assembly.

Bruce

[ericrobertlarson]

Bruce,


Thanks for the tip...reduced the gap from the factory 1/8" to 1/16", but no change. The unit still kicks off as soon as the igniter stops firing.


Eric

[nomad297]

Originally Posted by ericrobertlarson

Bruce,


Thanks for the tip...reduced the gap from the factory 1/8" to 1/16", but no change. The unit still kicks off as soon as the igniter stops firing.

Eric

Did you bend the igniter farther into the flame also?

Bruce

[ericrobertlarson]

Not entirely sure what you mean. I made them both closer together which brings the upper probe down into the flame more. Are you saying to bend the angle portion of both probes more so that it is closer to where the flame comes out of the burn tube?


No I did not do that. Can try though.


Eric

[ericrobertlarson]

Originally Posted by ericrobertlarson

Not entirely sure what you mean. I made them both closer together which brings the upper probe down into the flame more. Are you saying to bend the angle portion of both probes more so that it is closer to where the flame comes out of the burn tube?

Did that, but no change.

[Joe_GA]

If you buy a new igniter board, get the one from Dinosaur Electronics. It is superior to the originals.

Ignitor Board Index page

[U.S.ArmyVeteran]

You might try searching "Suburban SW6DE" on Youtube. There are quite a few Pro Repair type people on there with some great videos.

Good Luck!

[Rmcgee707]

I had the same problem. I was able to unplug the control unit for about a minute and plug it back in. It now works as it should. I purchased a new controller to have on hand. It’s been 6 months and still works. We live in the TT a week every months

[wmtire]

It can be the module board. It can also be loose connections.

That orangish brown wire at the bottom right of your heater that goes from the electrode back to module board ....have you made sure the spade connectors are tight at both connection points?

That electrode, besides making the sparks to ignite the propane also sends a millliamp signal back to the module board that tells it the flame is lit. This has to travel on that wire.

[Larry-NC]

Originally Posted by wmtire

It can be the module board. It can also be loose connections.

That orangish brown wire at the bottom right of your heater that goes from the electrode back to module board ....have you made sure the spade connectors are tight at both connection points?

That electrode, besides making the sparks to ignite the propane also sends a miiliamp signal back to the module board that tells it the flame is lit. This has to travel on that wire.

X2. This makes perfect sense.
The lighting sequence is obviously:
Force gas solenoid valve open and start ignition sequence.
After ignition timeout occurs:
Check flame sensor
If on, keep valve open
If not, if third retry, shut gas valve, set fault.
if not third retry, begin retry sequence

So the fault is failure to detect that the main burner has ignited. This could be either the thermocouple (tip is in flame, generates a low-voltage signal to control board when tip is hot), or the control board.

If I were you, I'd ignore the guessers ("Throw a control board at it") and disconnect the thermocouple at the board. Use your voltmeter on the lowest scale and measure the voltage while attempting ignition. If it shows around 70 millivolts during the ignition cycle (while there is flame), it's good--and the board is suspect. But more likely, the thermocouple won't generate voltage and is the failed part.

[MR.M]

many times it's just cleaning the igniter/flame sensor . very litely clean off any soot . they do not fail often and most likely it's the control board fail to read the flame sensor . surburban boards are cheaply made and fail quit often

[DouglasReid]

Originally Posted by Larry-NC

X2. This makes perfect sense.
The lighting sequence is obviously:
Force gas solenoid valve open and start ignition sequence.
After ignition timeout occurs:
Check flame sensor
If on, keep valve open
If not, if third retry, shut gas valve, set fault.
if not third retry, begin retry sequence

So the fault is failure to detect that the main burner has ignited. This could be either the thermocouple (tip is in flame, generates a low-voltage signal to control board when tip is hot), or the control board.

If I were you, I'd ignore the guessers ("Throw a control board at it") and disconnect the thermocouple at the board. Use your voltmeter on the lowest scale and measure the voltage while attempting ignition. If it shows around 70 millivolts during the ignition cycle (while there is flame), it's good--and the board is suspect. But more likely, the thermocouple won't generate voltage and is the failed part.

X2 to all the above. Ya beat me to it Larry!

[mnoland30]

Please let us know the outcome.

[scubasteve2112]

Just an FYI for other people with intermittent lighting. Our SW6DE would light sometime and not stay lit from day one. I replaced the ignitor which I broke when trying to adjust the gap. Then removed the burner and ground all the rust off the mounting surfaces. The reason for this is the control board sends a millivolt signal through the ignitor to see if the flame is lit. Guess I had band ground. Purge the gas lines by turning off the both propane tanks. Turned the burners on the stove to purge gas. Turned back off. On regulator selected left tank. Cracked valve on propane tank slightly. Could hear gas leaving tank. When it stopped opened valve the rest of the way. It lights every time!