Atwood water heater ECO and temperature thermostat

[theoldwizard1]

My daughter's family has a Jayco TT with an Atwood 6 gallon propane water heater. It has not worked properly since they purchased the trailer new about a year ago. They have had it back to the dealer 3 times without satisfaction (another story).

This unit has electronic (spark) ignition. After studying the diagrams I think I know what the problem is, but getting the correct part might be hard. Both the Emergency Cut OFF (ECO) and electronic water temperature switches (equivalent to the old fashioned mechanical thermocouple) have to be on for the burner to ignite. I don't think this is happening. The replacement pair from Atwood look a like and are not marked, so I assume they are identical.

I would like an ECO switch that is ON until the temperature is ABOVE 170F. If my understanding of the circuit operation is correct, the gas valve will stay closed until the water temperature switch calls for ignition and the gas valves to be open.



Does anyone know where I can buy a high temp ECO shut off switch that would work withe the Atwood water heater ?

[theoldwizard1]

Well, my daughter's family just got back from a 5 day trip. Water heater was non-functional most of the trip.

They are talking about going to an instant water heater, but none of the residential gas models will fit and the electric ones require 240V (they have a 30A connection).

They are concerned about their HOA so they don't want to keep it overnight so I can do more diagnosis.

[theoldwizard1]

Old-Biscuit wrote:

That could be spark electrode position....has to be directly in flame (tip should get RED) and gap set at 1/8"

Definitely RED and they paid $70 to have the service center "adjust" the position.


All wires and connectors are NEW and appear to be clean. The Temp and ECO connectors have been cycled several times now. It wouldn't hurt if I removed and re-seated the circuit board connector.

Let's hope that one time was a fluke !

[jetcare]

I don't think I have ever found a bad ECO. I do see the thermal fuse breaking down causing intermittent operation. If I have intermittent operation, I change the thermostat and ECO kit and the thermal fuse.

[Old-Biscuit]

OK.....

ECO opening is a real long shot.
If it was opening early it would continue to do so.

2 nights of use and 1 non-relight.
That could be spark electrode position....has to be directly in flame (tip should get RED) and gap set at 1/8"
That could be ground issue.......either at spark electrode assembly (bracket/mount screw not tight/clean contact)
That could be loose spade/terminal contact on t-stat/ECO
That could be connector contact issue at circuit board
That could be gas solenoid terminal/spade contact issue
That could be a fluke

Poor or corroded wire connections cause most of the intermittent problems in water heaters.

And no grease or dielectric sprays etc.
T-stat and ECO must make clean constant direct contact with tank wall.
Terminals on the t-stat/ECO should not move and wire spade connectors should go on the terminals tight.


1 non-fire is not a real issue.....if it continues to not fire up --- that is an issue

[enblethen]

Make sure the springs are holding the ECO and thermostat tight to the tank.
Make sure the tank is clear of any corrosion. Use wire bruch to clean.
No, do not use any chemical between units and tank.

[theoldwizard1]

Old-Biscuit wrote:
That t-stat with round pin was the problem.....it is set to OPEN at 160*F and close at 130*F

They never got installed.

Old-Biscuit wrote:
Original issue could have been as simple as dirty contact on circuit board connector, loose spade connectors on terminals or t-stats not being held tight to WH Tank wall.

Who knows what the original problem was !

My daughter's family is out camping. After 2 night, there has only been 1 time where the water heater did NOT re-light. Still frustrating, but I don't think that we will ever solve it.


EDIT : My "gut" feel is that the ECO is opening. Why I don't know. Any type of "thermal grease" that would help transfer the tank temperature to the thermostatic switches ?

[Old-Biscuit]

That t-stat with round pin was the problem.....it is set to OPEN at 160*F and close at 130*F

As posted earlier
Correct t-stat (small terminals) Opens at 140*F closes at 110*F
ECO (large terminals....same one used for both standard and XT models) Opens at 180*F and closes at 150*F

Wrong t-stat/correct ECO....overheating due to high temp set point of wrong t-stat

Original issue could have been as simple as dirty contact on circuit board connector, loose spade connectors on terminals or t-stats not being held tight to WH Tank wall.

[theoldwizard1]

UPDATE !

Re-installed the ORIGINAL thermostatic switches. I confirmed (12V test light) that the switches were both closed when the tank was filled with cold water. It took a couple of attempts for the burner to start (air in the gas line), but it did. It also shut down "properly".

Waited a few minutes and the turned on the hot water tap. Confirmed 12V in to the the main thermostatic switch. Could not confirm that that the ECO switch was closed (no DMM handy), but the darn thing fired up !

We will see what happens after a weekend of camping !

[theoldwizard1]

dougrainer wrote:
Your other theory, REPLACING the Appliance. What will replacing it do?

That is a "frustrated consumer" response. After 3 returns including being charged $75 for a burner "adjustment" (which is not covered by Atwood), my daughter has given up on that dealer.

dougrainer wrote:
Now, it is EASY to test the ECO theory. When the unit fails and you are there and the Circuit board starts the Ignitor, just test for 12 volts to the Gas Valve or each side of the ECO spades.

I will !

[Old-Biscuit]

Fault light cause main fl;ame is not lighting/proving lit and circuit board has made 3 attempts.



When spark is firing 12VDC would be on ECO and AT gas solenoids



If this issue is occurring while using the 'round pin' t-stat (how anyone connected a spade terminal to that round pin :H)

Anyway...get the correct set of t-stat/eco and foam cover


THEN retest WH

And IF you really wan to test temp of water ...use a thermometer in a glass running straight hot water from closest faucet.

[enblethen]

You can test the coils in the gas valve. Separate the wiring test each coil separately. They should have nearly the exact resistance.

[jetcare]

The thermostat ECO kit with foam insulation is Atwood 91447. You can buy the entire kit for $15.00.

[dougrainer]

theoldwizard1 wrote:

enblethen wrote:
Clean the circuit board connector.
Clean the gas burner tube
Test the ECO and thermostat while in the water heater

This unit is about 1 year old. The dealer has cleaned and adjusted the igniter and burner at a charge of $75. (Personally, I think the whole unit should be replaced, but the dealer has pretty much just thrown in the towel.)

Testing the switches while they are installed is difficult because you really don't know the temperature of the water/tank. My theory is that the ECO switch is (incorrectly) open when the temp switch is closed.

OK lets accept your theory of ECO failure. SIMPLE-REPLACE the ECO. I doubt the ECO is opening if the Main tstat (130-140) is opening and closing. I believe the ECO is a 180 trip(don't have my specs at home). Your other theory, REPLACING the Appliance. What will replacing it do? There are only 3 parts that can affect the operation (really 2). I will dismiss the Main tstat since it allows the ignitor to spark. Either the Circuit Board or the ECO will cause this problem. You have a BAD dealer. He should have called Atwood (since it is obvious he has nobody that knows what they are doing) and stated the complaint. They would have advised him of what I just stated. So, he would replace the ECO FIRST and then if the problem remained, replace the Circuit Board. Now, it is EASY to test the ECO theory. When the unit fails and you are there and the Circuit board starts the Ignitor, just test for 12 volts to the Gas Valve or each side of the ECO spades. LONG SHOT would be a bad gas Valve or something cloggiing the orifice in the gas valve intermittantly. To TEST a possible bad gas valve, you tap it with a hammer when the unit tries to ignite. IF it then lights, you have a bad gas valve. This is NOT always a good test but one that should work since the unit does light consistently. Doug

PS, YES a competent Technician WILL know the temp of the water when testing.

[theoldwizard1]

enblethen wrote:
Clean the circuit board connector.
Clean the gas burner tube
Test the ECO and thermostat while in the water heater

This unit is about 1 year old. The dealer has cleaned and adjusted the igniter and burner at a charge of $75. (Personally, I think the whole unit should be replaced, but the dealer has pretty much just thrown in the towel.)

Testing the switches while they are installed is difficult because you really don't know the temperature of the water/tank. My theory is that the ECO switch is (incorrectly) open when the temp switch is closed.