What I am looking for is.. how the radiant is piped to the machine. We have got to get you a thermometer. My thinking is that if the fault was high pressure/low water then the issue is with the geo loop side of the system and not the radiant floor. Turning off the water to water may have reduced the load enough to prevent the fault. There are many people in the geo biz that just do not get water flow requirements as they apply to the dynamics of heat transfer, including the manufacturers and there reps. A case in point is using one size fits all push/pull flow centers instead of sizing a single pump to the needs of the machine and the head pressure of the loop field. At the very least it is possible to install an ECM drive pump and set it to the flow needs of the machine.