Atwood Water Heater DSI Fault

Wow I have not heard of this before. Is your pressure relief valve leaking and shorting out these items? When mine leaked it ruined the safety fuse. I made a sht mtl shied to protect the wireing from the water drips, then finally reached the relief valve.

Are you using GENUINE Atwood replacement parts? I have never had or heard of multiple failures on a Atwood tstat/ECO system. Are you using the 130 or the 140 tstat/ECO replacement. Doug

Temperature and Pressure Relief (TPR) valve is not leaking (all is dry within the water heater compartment). The replacement ECO and TSAT was the part number identified in the Attwood owners manual (91447)...in short "yes" they were Atwood parts. I think my next option is to bring it in for professional troubleshooting/repair. My fear is they will replace the bad parts (ECO/TSAT) like I have done before and it works for one or two trips and then back at square 1.

Need to check for AC Ripple.........

Using a multimeter in the AC Volt mode test the DC Voltage to water heater.

AC ripple is result of converting AC to DC...how much depends on diodes/capacitors

AC Ripple above .8V can cause damage. If high AC Ripple then converter is not filtering the DC.


Also.....area on tank needs to be Clean and Smooth when t-stats make contact

I checked both input voltages (with AC and DC remote switches on) as you prescribed. Received 1.0 - 1.1 with digital multimeter on the AC mode. As you indicated, this suggests the converter is not filtering properly and may be causing the ECO and TSAT devices to be damaged. Does this mean a new converter...or is there something that can be adjusted/repaired on the converter? By the way...thanks for your assistance.

Callen42 wrote:
I checked both input voltages (with AC and DC remote switches on) as you prescribed. Received 1.0 - 1.1 with digital multimeter on the AC mode. As you indicated, this suggests the converter is not filtering properly and may be causing the ECO and TSAT devices to be damaged. Does this mean a new converter...or is there something that can be adjusted/repaired on the converter? By the way...thanks for your assistance.

According to Atwood, if you had any type DC/AC ripple or current problem it would take out the Circuit module, NOT the tstat/ECO. Atwood has never heard of this type failure, only the Circuit Board failures from AC/DC Converter or ripple current. The tstat and ECO is just a bi metal disc. I fail to see how a current problem would make that fail without damaging other electronics in the RV. Doug

Usually the sign of a failing capacitor(s) in converter

I assume if the circuit board was damaged or not working properly, the water heater wouldn't work at all when I bypassed the ECO & TSAT. I guess its time to bring it to the RV shop...I don't like being defeated!!!

Before you assume the board is bad again I would go to the Attwood web site they have a nice trouble shooting section there and they show how to check the board and other components. You have a new system, is your board a potted board or a regular board where you can see the soldered components. On the later you can remove it and look for burned components or tracks. As I said in my first post I never heard of this before, but if you have replaced 5 or so EOC and TSTATS it sounds to me like something must have been wrong from day one, because it sounds like you have replaced an ave of two per year since you got the MH assuming you bought this new. Old Biscuit is very knowledgable and has helped me in the past and may be he can explain AC ripple better, but I would check the power wire I believe it is brown and see what the voltage is on that wire. Just logically thinking to short out these items the voltage or current would have to spike very high.

We have had this problem since we purchased the MH...about 2 years ago. We did purchase it used and our first trip out yielded the problem...previous owner said he never had the problem before (take that for what its worth). The circuit board is potted, so no real accessibility to the components, however, visual inspection does not indicate any obviously burnt components. I wasn't planning to replace the circuit board again...all indications suggest it is functioning properly (sending signal to light burner, shutting down when TSAT and/or ECO are manually disconnected, etc.). I am certainly leaning more towards some incoming power deflection or spike that is taking the ECO and TSAT out (but somehow not affecting the circuit board). I keep trying to find a common denominator when the items fail...i.e. connected to shore power, operating on generator or dry camping? And I really cant put my finger on any specific configuration that seems to be causing the failures. My next checks will include checking water heater incoming DC voltages (and probably ripple voltages) under different conditions (connecting/disconnecting shore power, connecting/disconnecting to generator, etc.) to see if the voltage spikes or varies to any obvious degree.