We experienced the same thing with our piece of crap High Point. 2016 Landmark 365 Syracuse bot 10-16-16.
I bot a new oven thermometer and double checked that with my digital, remote, double probe BBQ Thermometer. Set oven at 425°, thermometers were 325° & 330° respectively. @ 350° therms were about 275°. The oven butned in the left rear and right front. We are on the road so it took from early December to about 3 wrks ago to get it replaced. The manufacutrer reported to Heartland that my old one worked fine but can run about 25'ish° off.
Did an 8#, 3 bone prime rib yesterday. It was room tp going in. The temp set at, 425°, pre-heated to about 350°. When the roast was cooking, could not get temp above about 310°. Came out delicious, took longer to cook by about 20-25 minutes.
Plus this cheap piece of junk does not allow turning
off turn table, sensor cook or warming cycle.
With the turntable always moving, you are very limited as to what you can cook due to height and size limitations.
Heartland should be ashamed they put this junk in an expensive RV. Maybe its a brother-in-law deal.
My neighbor,in this RV park in Indio, also from Eugene area, has a 2016 Mobile Suites 40', with a whirlpool conv/micro. Way better than Heartlands product.
We are shopping now but will buy when we don't have to pay Cali sales tax back home.