Gas water heater not turning on

I had a similar issue and it was the THERMAL fuse. Not sure what model you have but there is a section that has a small hose covering a pigtail containing the fuse itself.

It is a 99*C and can be purchased in packs of 5 for cheap or the pre-made pigtail for a bit more.

jmatteis wrote:
Not sure if I have the same issue... new trailer, with atwood 6 Gallon LP water heater. when I turn on the heater inside, dsi light is on, goes off, and the heater tries to light. Does this 3 times before staying in a fault state. I have gone out and watched the heater when it does this. I have no spark, it opens up for a few seconds then turns off. If I light it manually with a BBQ lighter, it stays lit for that few seconds, but then goes out and the heater does that same cycle twice more. Have tried removing the inline Thermal cutoff, and plugged the lead in direct, still the same issue. Lines should be bled, as the stove, heater and fridge all work fine. Propane tanks were new when we got it, but purged before filled. It is under warranty, but thought if it was something I could fix on my own, I'd love to do so before towing it to a service center.

I have checked the 2 amp on board fuse, it's good, as far as I can tell all fuses in the inside panel are good as well. There are a couple of LED's on the board that I have never seen lit, so don't know if they are diagnostic or not.

Best to start a new thread, rather than asking here.

Late to the party here, but you are giving it a minute to heat up the thermocouple?

If you "let go" of the light setting two quick, the gas shuts down.

Not sure if I have the same issue... new trailer, with atwood 6 Gallon LP water heater. when I turn on the heater inside, dsi light is on, goes off, and the heater tries to light. Does this 3 times before staying in a fault state. I have gone out and watched the heater when it does this. I have no spark, it opens up for a few seconds then turns off. If I light it manually with a BBQ lighter, it stays lit for that few seconds, but then goes out and the heater does that same cycle twice more. Have tried removing the inline Thermal cutoff, and plugged the lead in direct, still the same issue. Lines should be bled, as the stove, heater and fridge all work fine. Propane tanks were new when we got it, but purged before filled. It is under warranty, but thought if it was something I could fix on my own, I'd love to do so before towing it to a service center.

I have checked the 2 amp on board fuse, it's good, as far as I can tell all fuses in the inside panel are good as well. There are a couple of LED's on the board that I have never seen lit, so don't know if they are diagnostic or not.

Bob/Olallawa wrote:
Clean the contacts at the board and try again. If that doesn't do it, it sounds like a new control board is in order. If warranty is still good take it to the dealer if not order a dinisor board replacment.

No. People make this mistake so frequently the Atwood manual even has a warning about NOT replacing the board. They hardly ever fail.

Some of the older Atwood water heaters had issues with loose connections to the board. I actually had to put a metal binder clip on the harness connector to keep it tight. Eventually I also had the ignitor burn out. That was a $10 replacement. The ignitor did spark but the flame detector portion stopped working.

lots of answers. OP did you get it working?

Old-Biscuit wrote:
Good grief........

Your spark electrode is double duty.
Provides pathway for High Voltage Spark to ignite the gas
THen it proivides pathway for the 'rectified' current produced by the flame burning that is used as the flame priving signal ----just milliamps but enough for circuit board to sense that dc current
W/O circuit board receiving that signal it drops DC to gas valve so raw fuel desn't accunulate

You have gas flow (cause you CAN lite it with BBQ lighter)
You have Spark cause you can hear it CLick, CLick, Click
Circuit board is sending the DC to gas valve/spark electrode and is locking out the operation after 3x failed attempts (Fault Light comes on)

*Spark electrode gap ---too narrow/too wide ---no ignition (1/8" - 3/16")
*Spark Electrode wire connection...MUST be clean and tight. High Voltage can flow but the milliamp current can easily be stopped
*Spark Electrode MUST be engulfed in main flame when it ignites otherwise milliamp signal will not be sensed
*Spark Electrode must be clean...no soot.carbon----clean it using emery cloth
*Flame Spreader Plate (round disc) at end of burner tube must be squared/parallel with end of burner tube to properly spared flame out when it ignites
*Grounds.......MUST have good clean/tight grounds
*Connection at/on circuit board must be clean/tight

This is the correct answer

Good grief........

Your spark electrode is double duty.
Provides pathway for High Voltage Spark to ignite the gas
THen it proivides pathway for the 'rectified' current produced by the flame burning that is used as the flame priving signal ----just milliamps but enough for circuit board to sense that dc current
W/O circuit board receiving that signal it drops DC to gas valve so raw fuel desn't accunulate

You have gas flow (cause you CAN lite it with BBQ lighter)
You have Spark cause you can hear it CLick, CLick, Click
Circuit board is sending the DC to gas valve/spark electrode and is locking out the operation after 3x failed attempts (Fault Light comes on)

*Spark electrode gap ---too narrow/too wide ---no ignition (1/8" - 3/16")
*Spark Electrode wire connection...MUST be clean and tight. High Voltage can flow but the milliamp current can easily be stopped
*Spark Electrode MUST be engulfed in main flame when it ignites otherwise milliamp signal will not be sensed
*Spark Electrode must be clean...no soot.carbon----clean it using emery cloth
*Flame Spreader Plate (round disc) at end of burner tube must be squared/parallel with end of burner tube to properly spared flame out when it ignites
*Grounds.......MUST have good clean/tight grounds
*Connection at/on circuit board must be clean/tight

Clean the contacts at the board and try again. If that doesn't do it, it sounds like a new control board is in order. If warranty is still good take it to the dealer if not order a dinisor board replacment.

way2roll wrote:

er78mph wrote:
I definitely have gas, I bled the system, and it's an Atwood water heater. I'm just sticking a log lighter when I hear the gas and it stays lit for a few seconds and then turns off.

Sounds like the air mixture sleeve or the thermocouple/flame sensor. Can you slide the perforated sleeve to let more or less air in? Too much air and it will blow itself out, too little and the flame won't be strong enough.

Does the stove top light and stay on?

There is also the possibility you have a clog or something in the flame port. I used to get stink bugs in mine I would have to pull them out with tweezers. Mud daubers will clog them too.

Insects clogging things up is why I bought this screen for my water heater, and these screens for the fridge, and these for the furnace. Seemed like cheap insurance to just avoid the problem. Took about 30 minutes to install all 3 sets.