Sounds like you're having a right old hard time of it.
I also have a gerkros without the digital bits, and it is running grand for the past 6 months anyway, using about a ton every two months. New build and on a fair bit.
When I was having the thing commissioned, as opposed to installed, the chap said that he would turn down the output as the house wouldn't require the boiler running at its 24(?)kw capacity, and turned it down to 14 (?)kw, ? because it could be a little different, Xmas and all that has robbed me of those particular cells.
He said that it was quite simple as the kw output is a function of the rate of delivery of pellets, if the motor goes slower and doesn't deliver the things as fast, it gives out less heat. Thats how I understand it anywho.
So it has been tipping away, jingling for a while, then stopping, dingding.
House has UFH, and system running at 60 C, ish.
I think that it may be that the burner is receiving too much and not quite burning the lot, leading to excess ash, as such.
And having just reread your OP, its a 30kw boiler, in a 230 sq M house with UFH. My house is the same but sans buffer tank. My boiler is running as a 14kw, and haven't had any of the same problems, except for the melted cable, my bad tho, too near the burner, bad design ok, but hey should have seen it.
Only other problem was the dogs chewing on another cable, nearly fried themselves.
Unless your gaff is around 30 C inside when you've her running half the day, that excess heat output, coupled with build-up of ash, will cause lots of problems I reckon.
I only empty the ash once a week, if that, and there's no more than a pint glass full I'd say each time, with little build up on any of the internal surfaces.
I have other difficulties inside relating to the distribution of heat from the manifold, but reckon that its down to the system being improperly balanced. Where the feck did that little plastic chat for turning the valves go? Will bug me til the day I die.