Hi All- I have a self-installed 3 ton water to air unit from Ingram's. My only issue with it is that it will often throw a low-pressure fault after it has been resting for 5-6 hours or so. I don't care about the fault itself--the compressor always starts back up without issue after the one fault--I just want to make sure the fault isn't a sign of a bigger or growing problem. I have a 500' deep 1.5 inch closed loop that becomes 1" at the foundation entry point. The flow center is also 1" lines which then goes to 3/4" at the heat pump. (I supply these sizes in case there is some pressure gain/drop issue that someone might spot). The flow center is non-pressurized. I filtered the ground loop before hooking it up to the heat pump, and let it flush itself. In these screen shots you can see my data system showing one of the low-pressure fault events. I do set back the thermostat at night which is why I have these longer "rest periods" on my system. During the day, it has a more typical cycle pattern of 30 minutes on, 1 hour or more off (based on outside temp of course). It NEVER faults except after this prolonged rest period, and then ONLY one time. The left screen shot is the watt meter of the system showing the loop pump and the compressor running at 3kw, then the fault occurs and the fan runs by itself during the 5 minute fault at about 250 watts. The right screen shot is the flowmeter. Any ideas? Thank you!