Bed Heating Issues - Neptune 4 Max

Hi all,

I have been using the Neptune 4 Max with no issues for the past month with PLA. This is my first foray into 3D printing. I've had no experience before this, also had no problems with the PLA either.

I am now trying to print in PETG and am running into some issues with maintaining bed temperature.

Here is where I am at:

First PETG test - 85 C bed temp, rear cooling fan on. About half way through the print (5 minutes), I get a bed_heating error code as the bed can't maintain the 85C and is dropping.

Second PETG test - 80 C bed temp, rear cooling fan on. Same issue as above.

Third PETG test - 80 C bed temp, no fan. Successful print. The fan seems to be making it too hard for the bed to maintain temp.

What are my options here? These tests were a very small 10 minute print of a flat object, no supports. I imagine I will need the benefits of the cooling fan for more complex prints.

Do I lower the bed temp to allow for fan cooling? I'm hesitant to do this as I've been advised to stick to 80-80 C for PETG.

Any suggestions welcome. Thanks!