Gas water heater issue?

[lhemrick]

First of all the water heater works. It will run and heat up water but sometime during the day it will stop and I find the light on on the switch. The water will be hot and you can take a shower. It will not relight though. I left it off all night and the next morning it fired right up. Later that next day I found the light on again and barely had enough hot water to take a shower. At that point I decided to run all the hot water out. I tried to relight it would it wouldn't. Within 30 mins I got it to relight. I turned it off for overnight and got up this morning and relight it again. What Gives?

Thanks!

 

[Ernie n Tara]

Check the connections to the thermocouple.  They may be loose or corroded and losing contact when heated. Less likely are similar problems with other connections, particularly to the igniter.

Ernie

 

[Gary RV_Wizard]

The light comes on when it tries to light or re-light and fails. The water in the tank still remains hot for many hours thereafter, and warm for a day or two. The light is simply telling you that the heater has shut down because the burner is not working.

There are two common case where this happens:
1. The ignition cycle failed to get the gas burner to light after multiple tries
2. The burner did in fact light but the controller could not verify it. There is a flame sensor that reports to the controller, and if it does not report a flame the controller shuts the gas valve off and turns on the light.

You will need to observe which one it is to know how to proceed. The flame sensor is part of the igniter is a DSI heater, or a separate device for a pilot-light heater model. Which heater brand/model do you have?

 

[lhemrick]

It is an Attwood model G6A-6E. When the light is on it will not do anything at the heater when you flip the switch off and back on. It doesn't even click like its trying to fire or light. Let it sit for a while and it will fire right back up.

 

[Gary RV_Wizard]

Merely flipping the switch off and back on again resets the light and the lockout condition (or should, anyway).

If it doesn't, I wonder if the high limit cutoff switch is what is causing it to shutdown? It's basically a second, higher temp thermostat, and it won't reset until it cools down some. Not cold - just back down around standard tank temps (130-140 F.)

You can download an Atwood service manual here: http://bryantrv.com/docs2/docs/atwoodwaterheater.pdf

 

[lhemrick]

Well thats I was thinking when this issue arose. When I ran it out of hot water and cooled the tank down and it came back on shortly after I figured it was a thermostat issue. I was just waiting on someone to think the same.

Thanks!

 

[Gary RV_Wizard]

Could also be a circuit board that gets hot along with the water and one of its printed circuits opens up. Starts working again as it cools down. Had a similar problem with a circuit board mounted near the engine on my coach - it crapped out after 2-3 hours of driving, after it heated up enough.

 

[lhemrick]

I don't remember seeing a circuit board. Where would it be?

 

[jglass]

I ran into the same problem in my old motorhome.  I was running the water heater on the DC power converter without battery power.    Running to many lights or other devices lowered the coach voltage low enough to turn off the water heater.  Running the coach on shore power + battery power cured the problem.  Newer campers could be different.
Jim

 

[Rene T]

I don't remember seeing a circuit board. Where would it be?

Go outside and open up the access door to the heater. The board should be at the top right hand corner. Try unplugging the plug going to the board and clean all the contacts with a pencil eraser then plug it back in and try the heater again. Plug it in and unplug it a few times to clean the contacts inside where you can't clean with the eraser. I had an issue one time and it was caused by corroded contacts. When the heater would start getting the water hot, the heat would make things move and break the circuit.

 

[Gary RV_Wizard]

It doesn't look like a circuit board cause it is "potted", i.e. encased in a resin to protect it from water and such. It's where Rene described.

 

[lhemrick]

Came home this afternoon and the light was on again so I got out there and did some checking and cleaning. I pulled the thermostat and the eco. I put both is the freezer for a few minutes to cool them off because I have hot water ib the tank. Both ohm through when I took them out. I checked the grounds to everywhere. I have power to the thermo but no power to the eco. Is that not required to open the gas valve?

 

[lhemrick]

I just put the circuit board back in it and it fired right up. and now I have power to both the thermo and eco. CIRCUIT BOARD?

 

[William52]

A lot of automotive components have boards similar sometimes the old tap or wiggle test and things start working. usually a loose or cold solder connection. Sometimes u can repair. Depends how much $$$ for replacement.

 

[Larry N.]

...usually a loose or cold solder connection.

Or many times it's light corrosion on one or more contacts, and the motion cleans off the corrosion enough to work again.

 

[Rene T]

It was either a bad soldered joint or corroded contacts on the plug. Hope it stays running for you. Let us know in a few days after giving it a good workout.