[Wanderman]

431XE/12 the standard Aquahot for many years.

New everything in burner. Was working fine. Just removed burner Everything is got rust on it and the aluminum housing is showing white corrosion. Of course, AH will not stay lit.

What would cause all of this rust and corrosion and how to stop it??

Of course I have an extended trip coming up in early November.

I HATE Murphy!

[Trainer]

I suggest you wire brush corrosion and treat metal surfaces with Ospho, a brand of dilute solution phosphoric acid. Once dry, service the burner and have a fine trip.

[Wanderman]

Rudy.
It had big clumps of reddish brown crud on it and a fair bit of corrosion on the sides of the housing with the "wings." All over the pump, solenoid, etc. I have been running it for about 45 minutes every couple of weeks (to make sure it would be OK for the trip) When it started, ran and shutoff I figured it was time to clean the photocell, so took it off... nope was clean. And I found all that "gunk" Every part internally was new, so not sure what's going on, but right now it won't stay lit.

I can certainly try another nozzle, but this one is less than 4 months new and was started every 2 weeks or so.

It is the brass colored one rather than the older silver style... not sure if that makes a difference as the have the same spray values.

I so wish there was anyone semi local that could work on these and had lots of parts to test different scenarios. But there simply isn't.

Sadly, it WAS working nicely, albeit with white smoke for about 12 minutes on 2 week startup.

When at the factory, we drilled a drain hole in the exhaust and quite a bit of water/antifreeze mix came out...maybe 2 pints. So that had to be coming from someplace. I have been worried there is a crack somewhere in the boiler or neck, but it holds pressure so ????

You taught me well! So this one is very odd.

[Wanderman]

If I have the burner out, is there a way to spin up the motor with just the c-plug and a good power supply? Would like to test the individual components.

[Richard]

Have you tried cleaning the components, cleaning the photo sensor, replacing the nozzle, and aligning the electrodes? Just as Mr Aquahot recommended.

Start with simple first. Don’t make any assumptions about the nozzle based on age. Your white smoke was a clue the nozzle was not atomizing.

If it is lighting but will not stay lit: photosensor, fuel filter, computer

Are you sure it is lighting? Because just listening to the burner cycle through its blower on and blower off cycles can trick you into thinking it has fired off for a minute. When it burns, it also roars. Plus the exhaust pipe starts to get warm.

There are schematics of the C plug and B plug in the trouble shooting manual. Looking at them for a minute or two would reveal what to power to get the motor to spin.

If you are going to play with the Webasto unit outside the boiler tank, I highly suggest you disconnect the fuel lines. Else you could have a flame thrower on your hands pointed at you or the coach.

The trouble shooting steps in the manual are VERY good, I can appreciate your need for speed with the impending trip but there are no short cuts in figuring out why your burner won’t light.

In just reading what you wrote, you said water/coolant was drained from that area. Now you have tons of rust and corrosion. Sounds like you have a leak. You said it holds pressure. Are you losing coolant?

[Trainer]

Brass DanFoss nozzle is my choice.

Jumper or disconnect the coil wires will prevent firing but allow fuel spray to be onserved.

I wonder if the build up of corrosion you describe is a coolant leak into the U-channel chamber.

---

You can call me. 7 one 3. 8 one 8. 3234

[Wanderman]

Th gunk in the burner, was around/on the fuel pump, solenoid, etc. I lose about 1 Pint of antifreeze over a month or so.

I read through the manual and ran the troubleshooting. bear in mind no flamethrowers as it's on my test bench. It appears the bottom left is 12v neg to motor and then top 2nd one in is 12v pos. Though the color of the pos on my connector is red.

It is definitely firing up. The photocell is clean. It could be a simple electrical problem with the photocell wiring as I tested the cell itself. Light and Dark.

I am much more concerned with the gunk buildup and where it's coming from. Came off pretty easily, maybe it wasn't rust?

[Trainer]

With the burner out, pull the combustion chamber out of the heater and examine the U-channel chamber

[Wanderman]

Can you describe what exactly is the u-channel? I have the combustion out and clean.

[Trainer]

The chamber the combustion chamber came out of is lined with U-channels to pick up heat from hot exhaust gas. Should be clean, very little soot and no build up of leaked coolant