I am setting up a heated chamber for a rather large 3D printer that is almost fully enclosed. There is small opening at the top of the front plate of the printer. The heating element is 750W and placed at the bottom of the printer. A small fan pushed out the hot air from the heating element. Another 12V, 0.7A fan, placed near the top of the printer, forces convection in the build volume. The thermistor is placed about 600mm away from the heating element outlet, near the top of the printer, on the opposite side; far from both the fans air flows outputs.
Every time I try to set the heated chamber temperature to 55C, I get a heater fault, a few seconds in, signalling that the temp rise is much below the expected 1.8C/s. There is no way the thermistor would record such a fast heat up. It takes several minutes for the temperature to hit 55C and that is fine for my design needs. I set the M307 command to the lowest possible gain with A10. I don't understand what goes on behind the scene with the heater model using Bang-bang so I am clueless as to how to get this setup to work without a fault flag getting raised.
Note that I get a fault when I try to use M303 to find the model parameters.
Any advice would be welcome!