I’ll ask 1 question first, them go into what I think the problem is as mine has done this as well.
First off I’m assuming you have the Attwood model that has both gas and electric heating and electronic ignition. Most of the new ones are like this.
First the question. On electric operation. I’m assuming that you switched the actual 120 circuit breaker on? This breaker came new in 2004 I think. It is in the breaker panel and on mine is under the stove in the power box. It is the last breaker in the row. The HW heater has it’s own breaker so that people would not try to fire it with no water in it. This was an extra step in case some one flipped the rocker switch up by the tank panel. If this breaker is not on the unit will not get 120 power. The rocker switch light will be on, but no hot water will come with the breaker off on the electric mode. And when done camping, flip the breaker back off.
Assuming you knew about the 120 volt breaker and it was one, and you are trying to use it on gas or even electric for than matter and get nothing. Then this is most likely your problem or should be tried before you go to the dealer. This can happen on mine almost anytime bouncing down the road.
See this pic
See the Thermal cut off Tstat and Fixed Temp Cont T Stat. It is print T-STAT on the faom insulator. Basically it is a safety to shut the unit down if it over heats. And the push in wire connection going into the tank gets corroded or slightly gummed up and will not complete the safety circuit.
VERY carefully pull off the push on connection where it plugs into the tank and look for corrosion. If you can’t see it still push the connection back on/off a few times or worst case steel wool the male blade tip gently. Normally just the unplug and re-plug works.
Next would be plug unplug the 2 whitch connectors to the PC circuit board. They too can prevent a connection. You do not have to worry about the ignition wire. Right now you can’t get that wire even hot yet.
Once are done doing the plug/unplug then go inside. May have to open a window by the HW heater to hear, or have some one help you can you go look outside.
Fill heater with water.
Flip on 120 power at the breaker box if you want to use the electric option.
Now this step will tell you if you are making the safety circuit.
Flip on the propane rocker switch.
Listen for a “clunk” by the HW heater. It will occur about 3 to 5 seconds after you flip the switch. That is the gas valve opening.
Then listen for “click”, “click”, “click”. That is the electronic ignition trying to light.
The system will try 3 mini sequences to light then shut down on safety. It will stop firing the ignitor between each mini sequence for the gas to clear. After 3 trys, it goes out on saftey.
To reset the saftey, switch the propane rocker switch off, the electric rocker off if you had it on, then switch the propane rocker switch on again to get 3 more sequences.
Some times when the gas does not prime and due to air in the lines, you have to do 2 cycles, some times even 3, pending where in the gas line your HW heater is. To reset the system, both rockers, propane and electric have to be off.
Basically when ever I set up camp, first I try the propane option. If I hear the “clunk” of the gas valve and the click “click”, “click” of the igniter, then I know the safety circuit is working. I then flip off the propane and flip on the electric rocker and in 20 minutes I have hot water. The thermal cut off safeties work on both gas and electric mode. I do not even turn the gas on at the tank to test the safety circuit. After the first few clicks, I know it is working.
If I do not hear the propane option trying to light, I stop, flip off all gas or electric rocker switches and go push/pull that one thermal cut off plug and wamo, I’m back in action.
If this does not work, and you are handy with a volt meter and can read wiring diagrams, let me know we can get a lot deeper into this if needed.
Hope this helps and let us know how you made out.
PS After I did this a few times, it got better and now most of the time I'm OK, but every now and then it can still come back.