If you want to talk to someone who knows a bit about Engels, talk to Uncle Graham (not my Uncle) at EngelWorld, Midland, WA.
http://www.engelworld.com.au/en/content/4-about-us
Had a long discussion with him at a Caravan & Camping exhibition when we bought the 80L Combo in 2008.
He invited me up to his store where he gave us some Engel gifts. He took me out into his work shop and showed me the workings of many Engels laying dead in a corner.
He went into detail about a thesis he wrote for a local university about running Engels with a generator. Honda were going to take him to court but he proved his point and the action was dropped. Why you say?
Graham asked me what does a motor do when it runs out of fuel?
The only answer I had was, "It surges several times before stopping."
He pointed to the dead remains and said, "The majority of those dead Engel workings are the result of running them with a generator, even the later inverter models."
"Run your Engel at home with 240V from the grid but never from a generator."
"You could get away with running it from your 240V outlet on your generator many times but there will come a time you will run the genny out of fuel and poof it may possibly die.
If like many of us who venture into free camping his advice is and I swear by it, always run your fridge connected to a 12 volt battery when away from the grid. Plug a 240V/12V battery charger into your generator and keep the charge up in your battery. Surge in the power, even inverter models can pop a capacitor or other electronics necessitating a complete unit change out. (approx $1100.00 ten years ago)
Don't take this as gospel from me, no doubt there is something wrong with this explanation. Ring EngelWorld, Waeco, ARB etc if interested and get expert advice.
**BTW this advice is for any make and model of 12V/240V electronic controlled equipment.**