Odd noises and propeller stopping

Alex_28169

hi everyone, I just got this odd noises while heating up joule, the propeller starts working, then makes this odd noise, stops for a bit and restarts, it just keeps doing this while heating up then works fine. Any idea or past experiencias like this?

torridice_498271

Have you tried a cleaning cycle? Know how hard your water is? Hard water can cause the need to clean more often to take care of mineral build up.