Trying to install UM2 Hotend but print cooling fans won't turn on

[CME 0]

Hi everyone. I've owned the UMO+ for a couple months now, and recently I was able to get an UM2 hotend (the makerspace I'm part of upgraded their UM2). I found Neotko's wonderful guide on how to install it, and decided to test the heater, fans, and thermistor without installing it yet. I plugged everything in, and the heater, thermistor, and the hotend fan (the small one) work great. However, the two print cooling fans act strangely. I can increase the led brightness from the ulticontroller and it turns the fan plugged into the LED PWM port on, but when I turn the fan up to 255 on the ulticontroller, it does not even move. When I only plug a fan into the FAN PWM port, it works. I think this is a firmware issue. I'm using Amadee's firmware builder, but am not very experienced with it. Can someone tell me the settings I should use. If it helps, I have the 2.1.4 board. Thanks!

[neotko 1,402]

Umm

Um2 fans don't start to move until 70-90/255 they work with an option called Fan minimum PWM (set it at 80 on the @Amedee builder) and also use Fan PWM kickstart. 300 millisecs or more works.

Try this adjustments and build a new firmware. I think that should fix the issue.

[CME 0]

Thank you. I will try that. One more question though. The PTFE coupler in the hotend is burnt and probably should be replaced. Can I use the UMO+ one?

[neotko 1,402]

Nope sorry. UMO+ coupler is really really different to the UM2 ones. If you need to buy one I would highly suggest to get a TFM version + fixed spacer (any UM reseller has them or also 3dsolex TFT) since they last MUUUUCH more print hours. Is one of the parts of the upgrade that I love most since I don't need to change the couplers so many times. From from 50-200h of umo coupler to um2+ TFM/TFT 500-2000h is a BIG leap in time and money saving.

[CME 0]

Sounds good. I figured out that I needed a fan splitter, and I had one lying around. Works perfectly now. Thanks.