Homeowner Geothermal Questions
A homeowner can safely observe a geothermal system, but loop, pump, antifreeze, refrigerant, electrical, and instrumented water-side checks belong to a professional.
Safe homeowner geothermal matrix
| Level | What you may do | What to avoid |
|---|---|---|
| Green | Check thermostat mode and setpoint, filter condition, open registers, visible outdoor obstruction, visible water from a safe distance, visible error code, sounds, and smells. | Do not open panels, attach gauges, reset breakers repeatedly, add refrigerant, open loops, mix chemicals, or enter unsafe attics/crawlspaces. |
| Yellow | Stop operation and call Hartzell’s for loop-pressure or flow alarm, repeated lockout, unexplained auxiliary heat, water near equipment, frozen lines, low airflow, electrical smell, or repeated drain backup. | Do not keep testing the system to see what happens. |
| Red | Leave or call emergency services/utility as appropriate for gas odor, smoke, fire, carbon-monoxide alarm, exposed energized wiring, flooding near electrical equipment, suspected refrigerant exposure in a confined space, or unsafe well/drilling condition. | Do not book HVAC work before immediate life-safety steps. |
What the geothermal readings mean
| Reading | Professional use | Homeowner role |
|---|---|---|
| Entering water temperature | Shows the loop temperature coming into the heat pump. | Do not measure it yourself. Record any displayed code or alarm. |
| Leaving water temperature | Shows how much heat the system is moving across the heat exchanger. | Tell Dave whether the system is heating, cooling, or locked out. |
| GPM or flow | Shows whether the flow center and loop are moving enough fluid. | Do not adjust pumps, valves, or loop piping. |
| Loop pressure | Helps find air, leak, or loop-service problems. | Do not open the loop or mix antifreeze. Stop and schedule service. |
| Auxiliary heat runtime | Can point to capacity, controls, airflow, loop, or weather-load issues. | Note when Aux/Emergency Heat appears and whether it stays on. |
What Dave measures on a geothermal diagnostic
A geothermal diagnostic may include loop pressure, entering and leaving water temperature, flow or GPM, pump operation, freeze protection, electrical draw, controls, blower operation, airflow, static pressure, refrigerant-circuit behavior, desuperheater operation when equipped, and manufacturer operating targets. The current geothermal diagnostic is $348 flat when geothermal-specific testing is needed.
Related Hartzell pages
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Sources checked August 5, 2026
Utility, tax, and efficiency claims change. This page uses primary-source links for changing technical and incentive facts, and Hartzell verifies utility eligibility by service address before treating a rebate as real.