Giveb that ACiQ heat pumps are built by Midea, am I right to suspect that this thermostat is a re-branded Midea MTL04-1? That would make it likely compatible in HA/HB communication with recent Midea central heat pumps. I have a Midea system that was installed with a third party 24v thermostat and looking to upgrade

Yes, you are likely correct: the ACiQ TL04-1 thermostat is widely considered a re-branded version of the Midea MTL04-1 wired controller and is designed for direct HA/HB (RS-485) communication with ACiQ/Midea central heat pump systems, allowing you to fully utilize the system's variable-speed features.

If you have any further questions, please call us and we will be happy to assist you.