Hey Pony, have a 1.5kw HYE myself and it's been great as well, but agree re the controllers, they are fault prone.
Mine is a 2kw unit - large yellow box (500x500mm) with dual fans on the left, slotted vents on the right. These controllers are made by a third party and HYE just pass all support issues on to them so it takes a while to get a result.
The first issue I had was the display failed after a month in service, but the main issue I had was the controller would brake the turbine even when in NORMAL mode, this was caused by one or two of the three Mosfets at the left of the controller that switch in the dump load failing shorted.
They are the three under the silver bar at the top of this picture
Crystal from HYE sent a replacement card (takes around an hour to swap out) but that failed after about 3 months
So I took matters into my own hands and replaced the Mosfets with some from Radio Spares and wow what a difference, firstly I swear I am getting a lot more power now, especially in low winds and best of all haven't had a fault (touch wood) in months.
The odd thing is that the old Mosfets show a manufacturers mark of IOR - (international regulator I think) but they looked like knockoffs compared to the ones I sourced from Radio Spares,
The build quality looked different, even the laser engraving & markings looked different - so I reckon the controller manufacturer is knowingly or otherwise using counterfeit parts and this was the root of my particular problem.
Anyway, keen to hear if you got your controller issue sorted and if your problem was like mine and you need a hand fixing the Mosfets let me know as I'm getting pretty good at it now
If you found a good replacement also keen to hear what that was.