or a starving coil leading to low suction pressure despite a full refrigerant charge

this furnace relay S1-024-11772-700 is the primary diagnostic check for continuity

typically resetting between 250

digital round thermostat designed for precision control in 2-wire heat only systems

If the compressor won't start but you have 24V at the coil

Zonefirst TTS 7 Day Program Heat/Cool Stat Touch Screen R-410A or a starving coil leadingThe Zonefirst TTS is a professional grade 7 day programmable thermostat engineered for precise climate management in residential and light commercial zoning applications. This touchscreen HVAC control features a high contrast backlit interface that simplifies setpoint adjustments and schedule overrides, making it a preferred choice for contractors seeking a Zonefirst digital stat with high reliability. Designed for compatibility with most 24V AC