Dacor MCS130, 8 years old, will not heat past 375-400. Also, you can select Bake, Convection Bake, or Full Convection. Once the oven has been on a while, if you switch modes from one to one of the other modes, the "initial" temp displayed is never the same as the previous mode; i.e. if you're in Bake, and you're up to 375, and you switch to Convection, it will initially show maybe 345, where in "fact" you just left a 375 display in Bake mode. Then if you go to Full Convection, it might show 335. But none of the modes will ever get it go past a displayed 400 or so, and an internal thermo shows between 350 and 400 at that point. Screwey. ?

SOURCE: Dacor Oven - convection fan stays on while on "bake" setting

Question: does the unit appear to hold the correct temperature? Most convection units only turn the heating elements on and off...not the fan. If the unit is reporting operating temp and then taking other direction...and it is cooking right...you're done.

SOURCE: Convection Over with Dacor Millennia

We have the same issue anc alled Dacor. I seems as there is a problem with the oven as it was built with a faulty or missing temp control part. They have a fix for this problem by installing a temp control kit. you need to work through the warrantee group

SOURCE: My Dacor wont heat, broil or convection after self cleaning

like another person stated-from the front behind the door, take off the 6 screws and the cover by the latch. there is an "oven hi temp limit switch" It is crome with 2 heavy black wires connected to it. On the back side of this is a small red button which will reset the limit switch. I had the same issue (everything worked except the any of the heating elements) and quickly resolved.

SOURCE: Dacro Wall oven (electric) does not heat past 345 degrees on bake or convection bake but broiler works and bottom oven works fine (for bake, convection bake and broil).

it could be the oven temp sensor rod located near the top of the inside of the oven,or possibly the bake element has a hot spot on the element and can no longer pass enough current thru this spot to correctly heat to your settings a hot spot on the element will look discolored in this area