Atwood Water Heater GC10A-3E Propane Issue

[GeorgeP]

The propane burner shuts down after several minutes of operation with cold water in the tank. The DSI attempts to reset twice then locks out. During the reset process, there is an odor of propane. After several minutes, the propane function will work  again for several more minutes.

The electric side works well. The spark probe and thermostats have been replaced. The orifice, gas tube,burner tube and flue have been cleaned and lined up. The stove and furnace works fine with no interruptions. The air flow adjustment set at 1/4. The voltage is 12.6v under load.

When the propane works, there is good voltage going to the solenoids. After is shuts down no voltage to the solenoids. The flame is blue then turns yellow approximately half way out. When it works after a minute or two the burner noise gets louder and it sounds as if a strong breeze is blowing in to the burner area, although there is no wind at all. I have been told if the circuit board is faulty, the heater will not work on electric or gas? 

Where do I go from here?

Thanks for the help.

[tbutler]

You mention the spark probe, but I don't see a mention of the thermocouple which functions as a flame sensor.  If the thermocouple is bad, the circuit board never gets confirmation of a flame and it shuts the gas down.  If this is intermittent, the thermocouple may be failing but still working occasionally.  There may be a loose connection from the thermocouple to the circuit board.  If none of those I would look at a fault in the circuit board, something short of a complete failure of the circuit board.

[dickandlois]

George, The Fact that you can smell propane is an indicator, that the ignition board is a possibility.

Before you go there, check and see if there is a difference of how long the flame continues to burn when the access door is open compared to if it is closed. Does the unit run until the units shuts down because the water temp setting is hot enough? When the door is open?

The fact that the burner starts and then quits, restarts and the burner sound changes is an indication that the air to fuel mixture is off. 

Have you moved the air mixture tube while working on the unit? 

You mentioned that the flame was blue, but there is a large section of the flame that is yellow. Indication of insignificant air. The yellow portion should be as small as it can be with the access door closed. Hard to see, but the heater should sound more like it does when the door is open. The orifice should be as close to perpendicular as possible with the air mixture tube. It is nominal for the draft to change as the tube temperature rises, but if the area of yellow colored flame increases. There is not enough air entering the firebox. Air to fuel mixture is set to low.

The spark gap set at the proper spacing to insure a good spark and the ignition point is centered over the gas/air mixture path.

The ignition board will only try to fire 3 times and then go into a safe mode that requires turning off the circuit and turning it back on. 

Post your findings.

As Tom mentioned- the thermacouple will cool if the flame turns yellow and the airflow is restricted or bad therm thermacouple.

Note: if you see soot building up at the discharge area, the air to fuel mixture is rich, open the mixing slot just a little and keep trying different settings and it is a narrow band that will operate properly. 

Rich.       

[GeorgeP]

Gentleman;

Thank you for your quick responses to my issues and your suggestions. Mr. Butler, I had a new spare thermocouple. I installed making sure the connections were tight.

Rich, I adjusted the air flow and that seems to have solved the blue/yellow flame issue. The sound now is loud but steady. I no longer have the sound I described in my initial letter, and there is not a noticeable difference with the door open or closed, just more muffled when closed. I made sure everything lined up. There is no evidence of soot buildup. The spark is set at 1/8th inch as specified.

After all this was checked, the unit fired approx 2 minutes. After waiting several minutes, it fired up for another minute or so. I might add that in all cases the water was warm at best inside the tank. Again I appreciate the suggestions and if my responses prompt any other ideas, they will be appreciated as well.

George

[wildebill308]

Something I didn't see mentioned would be to use a pencil eraser to clean the contacts on the circuit board where the wires plug in. I hope you can find the problem. 

Bill

[GeorgeP]

Thank you Bill. This was one of the first things I have tried, it didn't seem to have any effect. Does anyone know if it is possible to test a circuit board, or does this take some special instruments?

George

[dickandlois]

George,

One needs a test fixture to really test the boards. Did you try and cycle the water heater with the door open, to see if the water temp reached the upper limit? Air flow difference with the door open can result in a difference then with it closed. Higher heat in the heating tube will increase air flow and if the flow is restricted by the door being closed. The flame can go out before reaching the cutoff temperature. 

Check the thermal sensors that are mounted on the tank are sung still making good contact with the tank. They use a sticky tape to hold them tight to the surface and it is a one time use item, so do not pull the sensors loose / off. Sure is starting to sound like the control board is acting up. Sounds like you have done all the test.

If you have run these tests then it sounds like its a control board. If you do not have the full manual go to this link. Page 14 covers things well !

 http://manuals.adventurerv.net/Atwood-Water-Heater-Service.pdf

Perform the following steps with POWER OFF to water heater. Good connections at all the Lettered Terminals. 

3. Manual reset ECO high limit switch-A should be depressed. Check for continuity between TERMINAL B and TERMINAL C of ECO.

4. Check for continuity between TERMINAL D and TERMINAL E of thermostat. If there is none, replace thermostat.

5. If water is insufficiently hot, insure thermostat is flush with tank.

6. Verify a good wire connection between ECO TERMINAL-C and heating element TERMINAL-F. Correct if necessary.

7. Check for continuity between heating element TERMINAL-F and TERMINAL-G. If none, element is bad and should be replaced. Do not over-tighten self-tapping screws when installing new element.

8. There should NOT BE CONTINUITY between element screw-G and flange of element. If there is, element has shorted. Element should be replaced.

9. Verify ground connection  

Rich.

[GeorgeP]

Gentlemen, I now declare victory for my propane issue. I finally installed a new circuit board and I now hear the sweet sound of burning propane. I thank everyone who responded to my request for assistance and firmly believe that more heads are better than one.

Thanks again

George 

[hermanmullins]

George,

Glad you resolved your problem. Thanks for reporting how the issue was solved. Many find one of the solution offered here to solve their problem but never report which one corrected their issue. Thanks.

 

Herman

[kaypsmith]

George, as Herman said thanks for letting us know what the resolution was, it is helpful to us as a means to help others.