Can it work in communicating mode on air handlers with X1 X2 X3 X4 instead of HA/HB?

No, the ACiQ TL04-1 thermostat cannot work in communicating mode on an air handler using an X1, X2, X3, X4 terminal layout because its communication protocol is specifically designed for HA/HB lines (typically matching proprietary Midea-family or specific inverter systems), whereas X1–X4 lines belong to an entirely different manufacturer communication protocol (such as Trane/American Standard communicating systems) that uses a proprietary digital data language the TL04-1 cannot translate.

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