To be honest unless someone reading this forum is familiar with this model I doubt you are going to get a precise answer.
Have you tried the handbook? Manufacturers often publish helplines for their products and you may find an answer there.
Unfortunately, I can see a reason why the fan may be running at full speed. The unit has a cold heat exchanger and unless sufficient air passes over it to warm it then it may frost up. If it does, the unit will fail to operate.
I can't say for 100% sure, so it may be worth checking more.
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