I have had my HDM for about a month. We filled the chiller with coolant to avoid algae issues. I am getting an E0 alarm.
This is supposed to be low tank or flow. We have checked the tank. It is full. I have followed the path of the hoses and nothing looks pinched or clogged.
When I got mine I had a similar issue. Review the wiring in the chiller, I had to correct a few mistakes. I think my OK and Fault lines were swapped and a NO vs NC contact swap. Luckily it is not a complicated device and mine was easier to correct than return/exchange. After the fixes it has run well for 2 years of hobby shop usage.