That's the same model HWH that I have in my 2016 Hurricane. I had a problem with 110V heating. After reading a post of wiring problems I pulled the cover off of black plastic electrical box on the back side of the HWH (under the sink on my coach). The cover of the box contains a relay. There are records in this forum of faulty wiring in this box and that is what I found to be the problem in mine. I'm attaching a pic. Considering the history, I would definitely confirm that you don't have a wiring problem in this box. If there is no indication of faulty wiring, it could still be that the relay in there is the problem although spraying the control board would doubtfully have any impact.
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