Webasto Air Top 2000 Stc Petrol De-coke Necessity?

[Shaun Witts]

My petrol Webasto gave up last week. I awoke in the night to a flashing error code (F 02 - Flame Failure), which usually resets OK but not this time.
When this has happened before, it was because the fuel level was too low, but the fuel guage was showing 1/4 tank, so I didn't think it was that. However, I filled up next day anyway, but the heater still wouldn't light and the error code eventually changed to F12 - Heater Lock-out.
I arranged for Exploria (installer 1 year ago) to look at it, and they were able to get a print-out from the ECU showing a summary of it's usage (who would have thought it was that clever? - How can I do that myself?) and noted that most usage had been at a fairly low level. That and the fact that the heater exhaust was fairly well sooted up, led them to conclude that the heater was coked up and they recommended that I run it at full blast for 20 mins or so every now and again (a bit like a diesel regen...).
However, that didn't fix it. They removed everything, and cleaned it out and re-installed it only to get a short circuit error, which they were unable to fix late last Friday. It's going in again on 1st Nov.

So, my question is: Is the recommendation to de-coke it every now and again, by runing it at full blast for about 20 minutes, a valid one?
Remember, this is a petrol heater, and apparently the diesel ones are not prone to this issue. I'm not sure if there will be any petrol owners on the forum, who use their heaters as much as myself, to give an answer, but I'm hoping someone will have the knowledge.

Thank you all.

 

[oldiebut goodie]

The diesel and the petrol ones both will suffer from sooting up if run constantly at lowest output. Ideally a heater should be serviced every couple of years depending upon usage.
"However, I filled up next day anyway, but the heater still wouldn't light and the error code eventually changed to F12 - Heater Lock-out." - you would need to prime the fuel line again if fuel level was too low, this can take 8/10 starts to fill the lines and pump again. Lockout is cleared by removing fuses and replacing.
Better to run your heater at full blast most of the time rather than lowest setting whichever fuel. The fact that you had flame failure several times points to starting to coke up before the final failure. I have had numerous heaters in that when checking the usage have been only run at lowest output - two new ones that someone had removed due to failure and both were severely coked due to incorrect usage. ( I presume that the heaters were over specified, ie they were 5Kw heaters when their requirements were more for 2Kw which could be run flat out as intended.)
It might be worth them checking the CO2 level in yours, it may be running too rich which can be adjusted.
Did they give you the diagnostics print out - if so post it up and I will see where the short circuit is, either glow pin or fan motor usually but servicing should not have caused a short unless they didn't insert the glow pin correctly.

 

[Shaun Witts]

Thanks oldiebut goodie.
I've been keeping the van at about 18 DegC (according to my thermometer placed in the rear beside the control), which is about 12 minutes-to on the control dial. I find this a perfect temperature when sleeping overnight (2 or 3 times a week), but this is obviously only a low level at this time of year. I'll have to remember to de-coke it every now and again - easier in winter.
They didn't give me a print out, and I think it was short circuit on the pump? they did say that they were going to get a new ECU in for when I return, just in case.