I have a eberspacher D5 on my boat which as been working perfectly until last night , it started up ok ran for about 5 minutes & then stopped & filled the boat with smoke it then restarted ran again for 5 minutes stopped & again filled the boat with smoke, the unit seemed to be putting more heat out then usual , it was decoked & serviced last winter , any ideas please PS I have just been back to my boat to check for the codes but found my controller has all white buttons, I don't think you can get codes on that type of controller