I bought these heaters expecting the controls common to earlier models, where one is able to adjust the fuel air mixture to achieve a lean clean burn. Not only is that not possible, there is no adjustment possible at all. It is supposed to have an automatic altitude adjustment, but it doesn't. It says either 0000m or 0001m. For reference, I am not at sea level, I'm at 310m here.
Additionally, the fuel pump has failed. It sucks air, adds air bubbles to the fuel going into the heater.
I have repeatedly tried to get some sort of refund from Vevor, but their system does not receive messages. I have tried to post messages multiple times, they just don't go through.
So now, I'm spending $60 to buy a whole new control set from a different company, the older style where one can control the air/fuel ratio and which can be controlled by aftermarket controllers like the Afterburner.
Very disappointed in Vevor, both for changing the design of the controller and their complete lack of attention to my case.