I installed a bed fan on my V0.2 (24V 5015) to speed up chamber heat up time and increase chamber temperatures. I tested that the fan can be run at 50%, any higher and it overpowers the bed heater. Heater can handle 50% fan, but when it kicks in, the bed temp still drops by 15°C for a short while (and then it starts rising again), but that dip causes Klipper to abort with error "Heater heater_bed not heating at expected rate". So I set verify_heater like so:
[verify_heater heater_bed]
max_error: 99999
check_gain_time: 99999
hysteresis: 20
Which eliminates the shutdown, but introduces another issue: by the time chamber heats up, the bed temp hasn't caught up to target yet, and print begins at sub-acceptable temperature.
Example: I set to print a part in ABS with 110°C bed, starting with a cold printer. It heats the bed up to 110°C. Then it starts waiting for chamber to heat up and turns on the bed fans. This drops the bed temperature to 95°C, where it stabilizes and starts to sloooowly climb back up again. By the time chamber reaches 50°C target, the bed is only at 100°C, whole 10 degrees below target.
However, because of that override, printer decides it's ok to start the print. But if I don't do the override, then the Klipper shuts down when bed temperature drops to 95°C.
How should I set up my Klipper so that it doesn't shut down when bed temperature dips, yet it waits for it to return to 110°C before starting to print?