Odd water heater behavior.....

[oldcarguy]

Our 2307C's water heater (Atwood GC6AA-10E 6 gallon gas/electric, electronic ignition) has developed an odd start-up glitch over the past few months.

After having the propane tanks shut off for transit, when we reach a new camp site it takes several start-up attempts to get the hot water heater to remain operating. I go through the normal start up cycle each time - open the propane tank valve, turn on a stove burner with a lighter flame next to it and wait for the burner to ignite, let it burn for 30 seconds to clear air from the lines, turn the burner off, turn on the water pump to pressurize the lines, open a hot water faucet and purge air from the water lines, then switch on the water heater.

I can hear the igniter click and hear the burner ignite, but it shuts off almost immediately. This cycle has to be repeated 3-5 times before the water heater remains on - once operating it runs until the water fully heats. Generally, once we've been through this cycle once, the water heater works normally until the propane is shut off at the tank and we close up the trailer for the next segment of a trip, although there have been a few occasions where we'll have to repeat the multiple start attempts after the water heater's been switched off for 18 hours or more.

I've been through all the basic trouble shooting and maintenance procedures (cleaned all the control board and limit switch contacts, checked the wiring, adjusted the burner flame, etc), also recently replaced a noisy propane regulator (which had no effect on this issue). The control board for this water heater is rather expensive, so I'm reluctant to replace it unless I can verify that it's failing.

Anybody experienced a similar issue, and/or have any thoughts on further testing procedures to try to pin down the problem?

 

[jon2bee]

I can’t help you, but use electric which we do. Why use gas unless you do all your camping boondocking?

 

[JackandJanet]

Oldcar - I'm in your camp and we always use the gas function of our water heater when camping, even when camping at campgrounds with full hookups. We also power our refrigerator with propane too. The reason is that I found when the Air Conditioner came on at some of these places, it would sometimes trip the campground circuit breaker if other things were also being powered by AC power. Now, this may have been due to poor facilities at these places, but I didn't want to come back to camp after being out all day and finding the refrigerator trying to run on DC power and the trailer hot from no A/C.

So, back to your problem. It sounds to me like you have purged the air from your gas lines, so there's something faulty at the water heater. I doubt it's the circuit board. If that thing were at fault, I doubt you'd get the heater to run on gas at all. Instead, I suspect you may have a fault in something like a "sail switch" or thermocouple that detects when the heater has lit properly and that cuts off gas if it hasn't. This thing may need cleaning.

I don't know anything more helpful, but there are members here that know much more about this system than I do and they will probably soon be along to provide much better advice. Regardless, I doubt your problem is a costly one to correct.

- Jack

 

[oldcarguy]

If we happen to be in a full hookup park we do use the electric side of the hot water heater, but probably 80% of our camping is in state or county park campgrounds (only partial hookups at best) so we're usually on a generator, solar, propane and a portable waste tank.

The water heater is an electronic ignition unit, so there's no thermocouple as such. It's possible that one or both of the two temperature limit switches could have a loose or damaged internal connection - a break in the circuit through either limit switch would keep the unit from working. The limit switches aren't terribly expensive, so I can try replacing them without breaking the bank.......

 

[sam-HILO]

Don't know if my advice will be correct.

We had trouble getting our refrigerator to light up on gas. Discovered that we need to light the stove and let it run much longer before trying to light up the ref. What would it hurt to try for five minutes before trying to light another appliance ? Keep us posted.

 

[campthewestcoast]

I have the same water heater and the same start up problem
I think it's the flame sensor next to the burner

 

[campthewestcoast]

Check for carbon build up and lightly clean with steel wool
Because it sends a signal back to the computer board the signal isn't as strong on initial start up as when the flame sensor has " warmed up" when the water heater has been running
You could try to replace the flame sensor
I left mine acting like yours for now

 

[campthewestcoast]

If you had failing limit switches the spark sequence would not happen

 

[JackandJanet]

Thanks, Les - A "flame sensor" problem was what I was thinking about, but didn't know what it was called. Oldcar - I really think this is your problem.

I had this problem on a hot air furnace in a house we owned. The repair guy just took it out and wiped it off on his pants. Worked like a charm!

- Jack

 

[Gary Rutledge]

"flame sensor" Dirty or failed. When a heat demand is given, after purge, igniter glows, gas valve opens, ignition occurs, sensor input (flame) is sent to board and valve stays open as long as flame is detected. If no flame is detected, unit will keep trying, a few seconds of gas, with or without flame, and with no flame,(detected) gas valve closes. Over and over.
Don't be upset. This situation is to let you know a problem is present. For your safety.

 

[Fishinmaui]

I have the same problem if I unplug the wire harness from the circuit board and plug it back up it lights. I think it’s the circuit board

 

[JackandJanet]

I have the same problem if I unplug the wire harness from the circuit board and plug it back up it lights. I think it’s the circuit board

OR - the wire harness connector is dirty/corroded and is not making good connections. Unplugging it and replugging it provides enough cleaning of the contacts to get the board working.

However, the sudden jump in power to the board may temporarily "weld" a cracked solder joint in the board. You can often find and fix these cracks if you have a soldering iron. I had problems of this nature in my old, 1991 Honda Accord and in my old 2005 F150. Once I located and fixed the cracks, I had no more problems.

- Jack

 

[oldcarguy]

Thanks for the suggestions - will have the trailer back here tomorrow before heading south for week at the state beach campgrounds north of Santa Barbara - will clean the sensor and see if that clears it up......

 

[RichR]

OR - the wire harness connector is dirty/corroded and is not making good connections. Unplugging it and replugging it provides enough cleaning of the contacts to get the board working.

- Jack

I've seen on other forums where the connectors to the control board were corroded and just needed cleaning. Get a can of contact cleaner and some cotton swabs and clean as well as you can. That is true for furnace control boards as well.