How to use Atwood water heater

[montreal]

Were still on our maiden voyage and getting to grips with the way things work.
I have the Atwood 6 gallon direct ignition heater but the instructions are not very good on how to use it. When I switch it on it give a brief flash of the red light on the switch.
After about 5-10 mins the light comes on permanently. The water is not hot. When I turn it off and back on the light stays out. What does this mean?
It does warm the water and its piping hot so it does work.
What is the logic and how long do I leave it on to warm up?
How long does it stay warm? Does the light stay on to tell me it's warmed up?
Also when the water is hot the switch will not ignite the burner. I guess this means it's hot and know's it's hot??

[240ClassicMH]

Ours acts in a similar way - usually takes 5 mins to be warm enough for doing dishes - perhaps 10 minutes for a nice shower. We always have it off when not in use just in case the water supply runs dry.

[Protagonist]

If your Atwood water heater is a combination propane/electric model like mine, the control panel has two switches with a light in between. One switch turns on the electric heating element, the other turns on the propane heating element. The red light in the middle is a fault indicator. If the light comes on, that means the water heater experienced some kind of fault and turned itself off.

First thing to check, is the water heater full of water? Easy to check, turn your galley faucet all the way to hot, then open it. If water comes out in a steady stream, no spits or spurts, the heater is full of water.

Next, check the water heater fuse. Both the electric and propane heating use 12v electricity; the propane side uses an electric spark to light the propane flame. If the fuse is blown, neither side works.

Next, see if the water heater is having the same problem on both propane and electric. Try it on one, then on the other.

If it acts the same both ways and the fuse is good, the most likely culprit is the thermostat. That's what was wrong with mine, a defective thermostat, caused by a wire being crimped when the insulation was installed.

On the other hand, if it works on electric but doesn't work on propane, or vice versa, then something else is wrong and we'll be getting beyond the limit of my personal experience.

[MrUKToad]

Although our unit is newer than yours, it sounds much the same. If you switch it on then the light should come on until the burner has fired up properly, then the light goes off. If the light comes back on again, the burner has gone out. If you can get it to work after trying again, i.e. the light goes out and the water gets hot then you're fine. As to the reason why the burner doesn't stay lit, well there are quite a few possibilities, unfortunately......

Our Atwood threw a wobbly on our third trip out and blew the Thermal Cutout, a sort of fuse thing that melts away and prevents the burner from firing. The reason? Spiders nesting the chamber where the propane and air are mixed. Big tut! Our dealer came to the rescue, sent a bloke out on a Saturday morning and he not only fitted a new cut out thingy and cleaned the spiders out, but he showed me what to do should it happen again; all for no charge, too.

[crazeevw]

If you're out on the road traveling daily, AND you have the 'engine-assist' on your hot water heater, this may be the reason you see the light come on after parking at your campsite.
Find where the hot water heater is located, and see if there aren't some 1" hoses coming off the back of the tank. If so, you have the engine-assist. The water in the tank is already hot, no need for the hot water heater to fire up.
Now, the next morning, or even after doing the dishes or someone taking a shower, then the flame will ignite.
Same thing happened to me first time out, took me awhile to figure this out, but it's the best conclusion I came up with.
Thanks, Derek

[Mike Leary]

Is there water coming out of the pressure relief faucet or the drain plug? Those Atwoods are good units, but need to be drained and cleaned + the the relief valve tested every year, which you can do without going to the shop. We are very carefull, especially in the SW of the USA, to avoid taking on "skanky" water. Our diesel has the "engine assist" pipes on our coach, and you could have a leak if you have them, also.