Dacs output a voltage and there is a current output if and only if you connect a load.
There is a first issue with the voltage output. Some additional hardware is necessary to output a full swing voltage between 0V and 3.3V:
Obviously these DACs can't power anything like an heater.
How do you monitor your heaters (link to technical specifications) ?
BTW, IMO this question would be more for the "General electronic" section rather than the "Microcontroller" section of this forum.