C-3721 error is displaying. How can I fix it?

Many Roomba manuals are available here: https://homesupport.irobot.com/app/answers/detail/a_id/843/p/3721/c/255;252 . The direct link to the US version of the manual for the Roomba 600 series vacuums is https://homesupport.irobot.com/euf/assets/images/faqs/roomba/600/legacy/manual/en-US.pdf . The 652 isn't listed separately. However, I suspect the 650 and 652 are very similar.

I hope this helps.

Cindy Wells
(Note: I found that Microsoft Edge worked better to display the Roomba support pages.)

c-3721 (fuser over-temperature)

http://www.sekonda.co.uk/documents/Sekonda_Tourbillon_Owners_Guide.pdf
yOU CAN TRY THIS LINK AND SEE IF IT WORKS... good luck

If you need further help, I’m available over the phone at https://www.6ya.com/expert/lynn_f08552ff80c75888

Since there is no 3721 in the service manual you mean 3751: Before I explain if this code comes back do not reset again these code deals with the fuser it can catch on fire that will ruin a perfectly good day

Lower temp on the fuser. To reset. On the right side of the machine just below the scanner section (The part with the big glass) is a cover next to where you connect the Ethernet cable. Remove the cover, with the machine on use a small screw driver and gently depress the small black switch. The machine is going to go thru some screens when you see the screen with the copiers on it to the left on the screen in the middle you will see a "." when that is displayed press 3. The code will come back but now press the Utility/Counter button, you should see a button that says Maintenance Mode press that, see Trouble Reset press that and the machine will again will go thru warm up procedure, you will see the "." DO Nothing! The machine should go to "Ready to Copy" if the code comes back. Have a technician look at it DO NOT CONTINUE TO RESET the code is for the Hot Part called the FUSER. It can catch on fire! And that will ruin a perfectly good day!!!!

Btw, I’m available to help over the phone in case u need at https://www.6ya.com/expert/normanj_7893313f0751935f

If this code come back after this procedure get a new fuser, do NOT reset and Reset dealing with the fuser it can catch on fire that will ruin a perfectly good day

1. Turn OFF the main power switch.
2. Turn main power switch ON while pressing the Utility/Counter key.
3. Touch [Trouble Reset].
4. Check to make sure that [OK] is displayed and it has been reset.
5. After turning off the main power switch, turn it on again more than 10 seconds after and check if the machine starts correctly.

Btw, I’m available to help over the phone in case u need at https://www.6ya.com/expert/normanj_7893313f0751935f

FIRST, if this code comes back. Have a technician look at it DO NOT CONTINUE TO RESET the code!!!! AS this is for the Hot Part called the FUSER. It can catch on fire! And that will ruin a perfectly good day!!!!


1. Turn OFF the main power switch.
2. Turn main power switch ON while pressing the Utility/Counter key.
3. Touch [Trouble Reset].
4. Check to make sure that [OK] is displayed and it has been reset.
5. After turning off the main power switch, turn it on again more than 10 seconds after and check if the machine starts correctly.

Btw, I’m available to help over the phone in case u need at https://www.6ya.com/expert/normanj_7893313f0751935f

fuser temp too high to reset turn off machine then turn on while holding down the utility/counter button when the trouble reset button comes up on the touch screen touch it and make sure it says ok then turn the machine off wait 10 seconds and turn back on if error code comes back fuser unit will have to be replaced

When quoting that error message, Konica told us the machine was disabled remotely by them.

was told this message meant Konica have disabled the machine remotely.