My ClimateMaster Tranquility 30 2-stage system runs normal to heat up the house and with supply temps going up to 108 degF. Just noticed recently during an extended cold front (anything below 30 in Houston is a winter storm!) that the heat cuts off whenever I use hot water in the house, and does not come back on! Fan continues to run without heat and supply temps drops to 60+degF. System model number is TTV072BGC01ARKS Based on the manuals, this is a: Tranquility 2-Stage Vertical 072 MBtuh CXM Controls HWG with internal controls Standard / Right Return / Top supply (TTV) / ECM motor The system is a closed loop, 300-ft deep well. All water connections appear correct (looking at the typicals in the manual, and matches the attached drawings). Not sure why or how the water heater can lockout the compressor? When I shut off all the thermostats and reset them, system runs as normal again. Any help or advice is greatly appreciated. Side note: Wanted to say what a great forum this is and all the posts and answers have been invaluable in helping understand how my geothermal system works.