aqua hot

Ok me and this thing have been going around, I rebuilt it a couple years ago it kept blowing a fuse and the light inside would just blink and wouldnt heat anything,
I found 2 bad bearings putting a extra load on motor blowing fuse went ahead and put on new tip ordered bearings cleaned everything up installed new photocell ( I broke in the process )
All done started it up run like a champ, clean and smooth,
Well we are a couple years later running smooth starting nice but it's like it heats up and I think it's kicking the flame out like it should and then the fan will keep running for awhile, but after burner kicks off the fan sputters while it's running eventually it will kick off shutting the light on the button off meaning it won't start again, unless I push the button then it will pop right off and run like new again,
I found bad radiator 13lb cap causing low fluid, found that and fixed topped off the coolant but it,s still doing it ? Won't stay on all night ?
I think it has somthing to do with the sloppy shut down instead of clearing the system and instantly shutting down,
runs perfect when running smooth quiet no smoke good hot water, overflow tank working properly now since the new radiator cap has been installed,
any ideas ??

Found out it was the siver brain box I switched out with a friend and worked fine ,
So anyone with an extra one please ship it my way :rolleyes:

Larry, looks like you are the " Go To " guy for Aqua Hot knowledge. Congratulations on finding the problem.

Well I hashed it over on the phone with another very educated gentleman on the phone for awhile, he is on another forum also,
And decided the symptoms of the continously sputtering purge he ask me if the box was clicking I checked and it was,
so my only 2 choices was to pull the box out and ship it off to be tested or find somone that had another brain box like mine that was willing to trust me with it for awhile, so we pulled my buddies and replaced in my unit and worked like a charm put mine back in and had the continuing sputtering purge again,
My box being bad I went ahead and opened it there are 5 low voltage pull downs and lots of diodes and capacitors,
The #2 relay is being the problem, when it's suppose to shut off and release the contacts it keeps getting sporadic little jolts of electric which pulls the contacts back closed and fires the fan again bump bump bump ? I held it in my hand while running and just touched the points on the relay for one second and it shut down holding it from bumping back in so it's still getting probably 12 volts to the #2 relay in spurts when it should not be receiving any volts, causing it to kick in the fan motor, ? I am going to do some more testing but it's really hard without a diagram of the inside of the silver box,?
on the good side on an older bus like mine the electric and the diesle are completely different systems so I still have heat with no brain box .)
Ahh, the Silver lining .)
If I can just get some duct tape and bailing wire I think I can get it up and running .)
Anyone have a diagram of the inside of Webasto Sg 1553/12v 287.962 or can find one ?