Atwood water heater won't light

[crazie_eddie]

Hi All

My Atwood g6a-8e water heater is refusing to light. The green light comes on on the control panel, but nothing happens - the red light doesn't come on either. Last year I replaced the thermostats, the igniter and the pressure relief valve. The fuse looks good. I've cleaned a bit of corrosion off the igniter and checked the various connectors too. And I have plenty of propane.

This happened once before and after checking all the connections and trying again, it did start then and has been working well for a month.

Could it be the circuit board?

Many thanks in advance...

Pat

 

 

 

[Kirk W]

2 minutes ago, crazie_eddie said:

The green light comes on on the control panel, but nothing happens - the red light doesn't come on either.

You must have something different from what I have experience with. On most water heaters there is a red light in the on/off switch that turns on when you first turn it on and again each time that it attempts to light the propane. That light then goes off when the control circuit board detects the heat of burning propane. 

[oldjohnt]

  There have been times (I was a used RV dealer)  when I removed the flat ribbon connector on the circuit board then lightly and gently polished the boards flat copper looking strip contacts using a pencil eraser and that cured the problem. Of course, you need a good solid 12 volt connection getting power to the board itself. On many units (not sure of yours) to see if the igniter is throwing a high tension spark, I use a jumper wire attached to the output terminal, turn it on  (FIRST see if the gas valve is opening???  you can hear and feel it and also check for power getting to it) and then see if you get the tick tick tick spark spark spark out of the igniter. You may be able to visually see if its sparking without the jumper wire method, but I have seen it when the ignitor itself is working fine (via the jumper wire method) but the ceramic encased ignitor tip has a short or hairline crack or carbon trace so the energy get discharged (ignitor working) yet there's no spark to ignite the gas. I have seen them mis adjusted to the proper amount of spark gap also. BOTTOM LINE THE GAS VALVE HAS TO OPEN AND IGNITOR TIP HAS TO CREATE A SPARK.

 Many units I've experienced have a red light come on when you flip the switch, but it goes out once she lights.

  If there's good solid full 12 volts to the board and the gas valve opens but no igniting the ignitor may be bad. Since your lights are acting strange (don't see right to me on a good working board???)  if there's good voltage to the board but no gas valve opening nor a spark, the board may well be the problem

 There can also be limit switches that are open causing failure to light, I just recently had one of those cause a heater to fail.

 Its best to look at your manual but if you don't have one try this link and see if that helps

http://youmaydownloadthem.com/atwood-g6a-8e-manual/

 

John T  Long retired electrical engineer and past RV dealer but rusty on this stuff so no warranty lol

Edited September 17, 2017 by oldjohnt

[crazie_eddie]

Thanks for the replies. When I hit the switch to turn on the heater, the green light comes on and stays on throughout the heating and after the burner kicks off. There's a red light that comes on if the burner doesn't ignite or if the burner doesn't re-ignite after it's successfully heated the water. This does happen a bit if I'm running more than the usual amount of hot water - a shower and doing the dishes.

Normally when I turn the heater on I hear a click and the burner firing up - now there's nothing.

John, I'll try the eraser trick as that was one connector that didn't look bad at all.

Pat

 

Edited September 17, 2017 by crazie_eddie

[oldjohnt]

1 hour ago, crazie_eddie said:

Normally when I turn the heater on I hear a click and the burner firing up - now there's nothing

Eddie, yep that's (click) the gas solenoid valve opening  (following a short delay) then the ignitor tip snaps snaps snaps if a spark is jumping the ignitor tip gap and you fire up. If you get NOTHING and the board has sufficient input voltage ???? it may be a bad board or an open limit switch or a resistive connection or the remote switch is bad or no tellin what else lol. Ive had to replace several boards over the years but before spending those bucks Id FIRST try to run some troubleshooting if the manual outlines any steps.

 John T

[lenp]

Does your water heater have a "thermal cutoff" installed between the thermostat and the control board?  The wiring diagram I have for your model shows it DOES have one.  Looks like the photo below.  If it opens you will loose 12 volts to the control board.

It is there to kill power to the unit in the event there is excessive heat buildup in the heater.  I will add a photo of the heater showing the cutoff in a different response.

Lenp

[lenp]

Here is where it is located.....

[oldjohnt]

lenp, good catch. As we know, nuttins gonna happen until you get power TO THE BOARD

   Ive had MANY of those (thermal fuse type device) go open in all sorts of appliances like coffee makers or microwaves or hot water heaters. I've also had to replace the limit type switch or T Stat located under that black plastic foam that fits right up against the metal tank where shown by the arrow in the picture above. EITHER of those will be a cheaper fix then his control board

 

John T 

Edited September 18, 2017 by oldjohnt

[Kirk W]

12 hours ago, lenp said:

Does your water heater have a "thermal cutoff" installed between the thermostat and the control board?

If it isn't there, it should be and while I have seen owners remove one to get the water heater running, it is a very bad idea to leave it out. The reason for it is that water heaters sometimes experience what is called a "flashback" condition where the propane will ignite outside of the burner tube, usually in the air shutter area that can be seen directly below the arrow in the photo posted by Lemp. 

I have removed one as a test and to do so would harm noting as long as you are there watching the water heater during the test but it is very risky to leave it that way after the test. There is a pretty good chance that Lemp is right and it is pretty easy to find and replace. Like a fuse, those can open just from old age or mistreatment. All that they are is a thermal fuse designed to open from heat rather than current flow. 

Edited September 18, 2017 by Kirk Wood

[Kirk W]

15 hours ago, crazie_eddie said:

There's a red light that comes on if the burner doesn't ignite or if the burner doesn't re-ignite after it's successfully heated the water. This does happen a bit if I'm running more than the usual amount of hot water - a shower and doing the dishes.

If you are saying that the flame does come on and heat the water at first, then quits, that is more likely to be caused by the thermostats. There are two of those mounted together under that black foam where the thermal fuse connects. One is in the positive side of the power and the other in the return and they have different set points. They are an item which fails and needs to be replaced and while not all techs do so, I always replace both at the same time as they can be purchased as a pair.

[crazie_eddie]

I tried by-passing the cutoff and still nothing.

Kirk, the flame doesn't come on at all, no clicking no nothing. And I have replaced the thermostats in the last 2 years - when I had problems with them the symptoms were different, as you say the flame would come on then quit.

So am I down to the problem being either power not getting where it needs to go or the circuit board?

 

Edited September 18, 2017 by crazie_eddie

[Kirk W]

Did you check Lemp's suggestion, the thermal fuse? Have you measured 12V to follow it from the connection to the water heater, then to the thermostat, then the thermal fuse, and to the circuit board? The circuit boards can and do fail, but they are also the most expensive item and if you buy one they will not allow you to return if it the package seal is broken. If you must get a circuit board, then I suggest you do so from Dinosaur Electronics. 

[crazie_eddie]

Hi Kirk, I did a quick check just trying to by-pass it. (Thanks for that tip Lemp!) Still no go.

I don't have any kind of tester, but I'm watching a You Tube video at the moment. He's saying if there is no clicking when you try to start the heater that the circuit board is probably bad. You are quite right though, I don't want to have to replace it unless I have to!

Pat

 

Edited September 18, 2017 by crazie_eddie

[oldjohnt]

 Eddie, still even a good circuit board needs power before it will work. As I noted I have had to replace the t stat UNDER THAT SMALL BLACK FOAM as shown in lenp's picture, and I have replaced the thermal fuse, EITHER OF WHICH can cause your problem. You will NEVER get that clicking gas valve operation until you have power getting TO a good working board via the thermal and t stat..........

A simple 12 volt DC tester with a light that glows upon 12 volts may find the problem. Attach the alligator clamp end to ground and probe with the sharp tip end to find 12 volts making the light glow.,,,,,,,,,,,,, Turn the unit on,,,,,,,,,,,,,,,look at the diagram lenp posted and see if the light glows on BOTH sides of the thermal (if ON input but not out, its blown open and bad) ,,,,,,,,,,,,,,,,,,,,then on BOTH sides of the T stat located under the black plastic foam (it should be closed until water is hot) ,,,,,,,,,,,,,,,,,,,,,,,,,,,,,Then if power is on and there's 12 volts to and through the thermal, then to and through the t stat,  then to the boards input, the valve should click open and the ignitor tip throw a spark IFFFFFFFFFFFFFFFFFFFFF the board is good...........

 Soooooooooooo before buying a new board insure its getting 12 volts which is via the remote switch,,,,,,,,,then to and through the thermal,,,,,,,,,,,,then to and through the t stat,,,,,,,,,,,,,then the boards 12 Volt input,,,,,,,,,,,,,,,,,,,then if the t stat is closed and the boards good the valve should click open and the ignitor throw its sparks until it times out if necessary and the valve closes again.

 This is fairly simple 12 volt test lamp or voltmeter testing Id try BEFORE buying a new board IT NEEDS POWER TO WORK

  As I referred to above, I was once on the phone with Dinosaur Electronics (manufacturers of circuit boards)  troubleshooting if I needed a new board or not, and they are the ones who told me to clean the boards ribbon connector strip contacts which cured a problem NO NEW BOARD REQUIRED..........If all the voltages test out Id still try that before deciding I needed a whole new board.

 Were all trying to save you some money hope it helps. 

 Keep us posted and post any more questions

 

John T

Edited September 18, 2017 by oldjohnt

[Kirk W]

2 hours ago, crazie_eddie said:

He's saying if there is no clicking when you try to start the heater that the circuit board is probably bad.

That might be true if everything else is as it should be but at this point, we really don't know if there is any 12V power to that circuit board. It could be something as simple as a fuse open on your main 12V distribution supply panel. Before you spend money throwing parts at the RV, visit Amazon Market or Walmart Store and get yourself one of the cheap means of testing for 12V. It will save you a lot of time, money, and grief to get one and learn to use it.  The problem could also be a bad ignition probe that costs about $30 or even a broken wire or blown fuse. 

Over 14 years (12 fulltime) in our last RV I replaced the water heater circuit board one time and the ignition probe 2 times. In 35 years of RV ownership and many times assisting friends with theirs I can recall using a circuit board 3 or 4 times and probably at least a dozen spark probes, several ECO assemblies, at least a dozen thermal fuses, one propane valve, and dozens of fuses. 

Edited September 18, 2017 by Kirk Wood

[oldjohnt]

2 hours ago, Kirk Wood said:

Over 14 years (12 fulltime) in our last RV I replaced the water heater circuit board one time and the ignition probe 2 times. In 35 years of RV ownership and many times assisting friends with theirs I can recall using a circuit board 3 or 4 times and probably at least a dozen spark probes, several ECO assemblies, at least a dozen thermal fuses, one propane valve, and dozens of fuses

 Kirk, sounds familiar to my experiences as a used RV dealer and over 40 years an RV user.  I've seen more blown fuses or no board power present and faulty ignitor tips then I have bad circuit boards. If we were there armed with a volt meter or even a 12 volt test lamp we could help him. Of course sure boards go bad and it may be that UNLESS its NOT getting power, that's the $64,000 question lol

 Eddie, run out to wally world or any hardware or auto parts house and buy a 12 volt test lamp. The alligator clamp end goes to ground and you use the sharp tip end to probe for 12 volts causing the lamp to glow at 12 volts PIECE OF CAKE....per my above guidelines

 John T

Edited September 18, 2017 by oldjohnt

[coachmac9]

I have the same problem that just started Saturday night Thanks for all the suggestions! One more question, might there be a fuse blown that controls the 12 volts going to the water heater or do they usually not have a fuse??  

[oldjohnt]

1 hour ago, coachmac9 said:

might there be a fuse blown that controls the 12 volts going to the water heater or do they usually not have a fuse??  

Mac, in my experience RV 12 VDC loads (lights, fans, furnace, water heater, fridge, water pumps, 12 volt appliances etc etc)  are fed from the 12 VDC distribution panel (served by the house battery) via fused branch circuits in order to provide overcurrent protection to prevent a fire, so yes Id expect a fuse in the circuit and that's the first place I look when there's an electrical problem. As the diagram above indicates, that 12 VDC source (likely fuse protected) has to jump through some hoops  (thermals, t stats, switches etc) BEFORE it can power up the circuit board.

 John T

[Kirk W]

2 hours ago, coachmac9 said:

One more question, might there be a fuse blown that controls the 12 volts going to the water heater or do they usually not have a fuse??  

There probably is one but it may not be specific to the water heater alone. Unfortunately, some RV builders do not have all fuses located on the common fuse block but use some of the "inline" fuse holders for some items, perhaps because they are cheaper than a later fuse block or possibly because it is easier to do. 

 

3 hours ago, oldjohnt said:

my experiences as a used RV dealer

I don't recall you having mentioned this until recently so wasn't aware that you were one.  So did you work as an RV tech, or as management? My experience is in troubleshooting and repair.

[oldjohnt]

1 hour ago, Kirk Wood said:

I don't recall you having mentioned this until recently so wasn't aware that you were one.  So did you work as an RV tech, or as management? My experience is in troubleshooting and repair.

Good evening Kirk, Actually (unfortunately) the vast majority of my work when I was an RV dealer was, like you, in troubleshooting and repair all the never ending issues encountered in dealing in USED RV's. It was up to meeeeeeeeeee to diagnose troubleshoot and repair a unit before offering it for retail. As an Electrical Engineer I was more comfortable dealing with electrical versus plumbing issues, but had to learn the hard way from experience how to fix the darn things grrrrrrrrrrrrrr. I was thinking back and actually its been 47+ years as a continuous RV owner and/or dealer, but these high dollar sleek units are beyond my ability, glad I'm retired now lol

 I will be visiting your great State in October, it would be a pleasure to visit, chit chat and sparky talk with you. Fun talkin with you as always.

Best wishes and God Bless Kirk

John T     

[Kirk W]

59 minutes ago, oldjohnt said:

 I will be visiting your great State in October, it would be a pleasure to visit, 

We should be around so drop me a PM and let me know when you expect to pass through north TX and your route. 

[oldjohnt]

Will do when the time comes, Thanks

John T

[coachmac9]

oldjohnt, we are a little farther north than kirk (Lake Tawakoni) area, if you ever need anything while passing through let me know!

[oldjohnt]

1 hour ago, coachmac9 said:

oldjohnt, we are a little farther north than kirk (Lake Tawakoni) area, if you ever need anything while passing through let me know!

Thanks coachmac, It would be fun to visit you and Kirk. We base around Austin in Nov and December or so before heading to Florida but we may travel to Coleman Texas sometime which is in your direction. I wont know any final plans until SWMBO and my daughter tell me LOL

 

 John T

[Kirk W]

8 hours ago, coachmac9 said:

we are a little farther north than kirk (Lake Tawakoni) area,

Mostly west of us, but you are so close, we should really make a connection!  If you are at the Thousand Trails park, we are less than 50 miles apart. We are midway between Canton & Tyler and just off of I-20.