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topher80's avatar
topher80
Explorer
Jun 13, 2013

DSI fault light on panel - Hot Water

I have a 2008 HR Neptune and on the inside panel (where all of the lights and indicators are, I have a 12V switch for hot water and a 120v switch. Above the switches is a small DSI Fault lite.

When on shore power and the 120 witch on it is not uncommon after a while for the DSI Fault lite to come on. I have a theory.

I am assuming that because we don't use all that much hot water that the DSI Fault switch is acting like a local circuit breaker because when that light comes on the water in the tank seems to cool down.

Conversely, when the 120v switch is on and there is no apparent fault (which make the like illuminate) the water is almost scolding it is so hot.

I ask the folks at camping world and they checked it out and claim it is related to the pilot on the gas side and that after the gas tries to ignite more than three times and it doesn't ignite it trips the fault.

Again, my theory is that the DSI fault light shuts of the electrical heater after it reaches temperature and after an extended period of time when no water is being drawn down from the tank.

Any thoughts, ideas? Thanks.
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13 Replies

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  • PFGuil49's avatar
    PFGuil49
    Explorer
    Jun 05, 2018
    I agree with Doug also. My water heater did the same thing as topher80 and drcarr57 on my 2005 Holiday Rambler Endeavor. While operating on just electric, the water would get scalding hot and trip the DSI light which pointed me to a bad TSTAT. I replaced both the TSTAT and EOC because you can buy them together in one package for $10 to $14 dollars. Everything’s working as it should again.
  • wa8yxm's avatar
    wa8yxm
    Explorer III
    Jun 05, 2018
    THe other thing that will light the Fault Light is overheat. I'm not sure how hot but there are Two Thermostats on an Atwood one is the "T-Stat" and the other is the "ECO" (emergency cut out)

    A bad connection on the ECO leads, or the gas solenoid, or temps over something like 180 or 190 degrees will trip the Fault light... Same as a no-flame.
  • pcguilford's avatar
    pcguilford
    Explorer
    Jun 05, 2018
    I just had the same issue with DSI FLT light on my 09 Jayco Eagle 345 BHS. While troubleshooting, I found the igniter harness had come loose from the igniter (on my heater it is orange harness RH lower side that connects to gold blower that heats the tank). Upon reconnecting the DSI FLT light went out and I was able to get hot water on electric and LP. My initial fault was that there was no hot water when running off electric only. I then tried the LP side and the flame would light for about 3 seconds then go out. I was informed by Camping World Service that the DSI FLT will shut down the relay panel that controls the water heater not allowing either side (electric or LP) to work - additional safety.
  • drcarr57's avatar
    drcarr57
    Explorer
    Jun 15, 2013
    I agree with Doug. My water heater did the same thing. After letting it cool down, the water heater started again. It is best to change the tsat and eoc, before the eoc fails too and your water heater really overheats. The EOC and TSTAT come as a package for between 10-14$.
  • dougrainer's avatar
    dougrainer
    Nomad
    Jun 14, 2013
    topher80 wrote:
    Thank you all for your comments. The gas switch is off, so it must be a weird thing...cause with the gas switch off it should not be faulting, right.

    Guess I won't be worried about it provided I have hot water on shore power.


    READ my post again. Your tstat is bad and the ECO is tripping causing the DSI fault light. THAT is the reason for your scalding hot water. The ECO trips at 180 degrees instead of the tstat tripping at the normal 130/40 degrees. Doug
  • dougrainer's avatar
    dougrainer
    Nomad
    Jun 14, 2013
    2chiefsRus wrote:
    dougrainer wrote:
    Diplomat Don wrote:
    The DSI fault light only pertains to the gas side of the water heater. If it's coming on when the gas is off and you're using 120 AC, then you have a weird issue where something is shorting out between the two systems.


    IF the Electric side fails to shut OFF (defective tstat) and the ECO trips the DSI fault light will come on. IF you have the unit on LP AND 120 at the same time and the LP side fails to light, the DSI fault light will NOT come on. Doug


    What is the ECO?


    Hi limit cut off. If the tstat fails, IT will open and shut the appliance off. Most ECO switches are at the 170/180 limit.

    ECO Electronic Cut Off Doug
  • 2chiefsRus's avatar
    2chiefsRus
    Explorer
    Jun 14, 2013
    dougrainer wrote:
    Diplomat Don wrote:
    The DSI fault light only pertains to the gas side of the water heater. If it's coming on when the gas is off and you're using 120 AC, then you have a weird issue where something is shorting out between the two systems.


    IF the Electric side fails to shut OFF (defective tstat) and the ECO trips the DSI fault light will come on. IF you have the unit on LP AND 120 at the same time and the LP side fails to light, the DSI fault light will NOT come on. Doug


    What is the ECO?
  • topher80's avatar
    topher80
    Explorer
    Jun 14, 2013
    Thank you all for your comments. The gas switch is off, so it must be a weird thing...cause with the gas switch off it should not be faulting, right.

    Guess I won't be worried about it provided I have hot water on shore power.
  • dougrainer's avatar
    dougrainer
    Nomad
    Jun 14, 2013
    Diplomat Don wrote:
    The DSI fault light only pertains to the gas side of the water heater. If it's coming on when the gas is off and you're using 120 AC, then you have a weird issue where something is shorting out between the two systems.


    IF the Electric side fails to shut OFF (defective tstat) and the ECO trips the DSI fault light will come on. IF you have the unit on LP AND 120 at the same time and the LP side fails to light, the DSI fault light will NOT come on. Doug
  • othertonka's avatar
    othertonka
    Explorer
    Jun 14, 2013
    It sounds like you are using the propane switch and the 120 AC switch at the same time, and when the propane side fails to light the "Failed to light (RED) comes on indicating that it indeed failed to light. `The water heater should continue to heat on 120 AC electric even if the indicator light is ON. A lot of people do run their heater on both for a quicker heat up. Is that what you areding when this happens?

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