Your geothermal heat pump has stopped heating or cooling, and the proposed repair says “add refrigerant.” If the home has a WaterFurnace GeoLink flow center, ask what the technician found on the ground-loop side as well as inside the heat pump. A comfort complaint or lockout does not establish which circuit needs work. Start by photographing the exact fault message and noting whether the system was heating or cooling. If it has shut down again after a reset, arrange service instead of continuing to restart it. The useful next step is a documented diagnosis, not a refrigerant order. Identify the heat pump and the flow center separately A closed-loop geothermal system exchanges heat with the ground through buried piping. The heat pump transfers heat between that loop and the house; the loop is not simply a long refrigerant line. WaterFurnace's explanation of geothermal heating and cooling shows why water-side performance belongs in a geothermal service discussion. Collect the model and serial number of the heat pump, plus the model of the GeoLink flow center if its label is accessible without opening equipment. Send both to the service company. A photo of the pump cabinet alone is an incomplete equipment file: it does not identify the heat pump's refrigerant or its required service specifications. The manufacturer's residential literature directory separates product documents and refrigerant versions. Match the installed unit to its own documentation. For a broader explanation of that check, see how to match refrigerant to equipment records . A lockout needs its exact message and operating mode WaterFurnace's owner's manual, printed pages 20–22 , describes protective controls for airflow, water flow and refrigerant conditions. Some equipment displays status lights; other systems report faults through a communicating thermostat. Use the wording from your equipment, not a light sequence found for a different model. Record the message, time, room temperature and selected mode. For example, “heating stopped at 7:10 a.m.; thermostat showed this message” is more useful than “the pump is broken.” Attach the photo and say whether this is the first event or a repeat. If the message disappears later, the original record still gives the technician a specific event to investigate. The same owner's manual advises calling the dealer when a shutdown recurs and cautions against repeated resets. Do not bypass a protective control. Ask the dealer what temporary operating arrangement is appropriate for your particular installation while you wait. If loop flow is questioned, ask for a measured result In the GeoLink Flow Center manual, IM1547EW 06/22, printed page 30 , WaterFurnace describes checking flow through the unit using the entering-to-leaving water pressure difference and the applicable pressure-drop/flow table. Insufficient flow can reduce capacity. That is a reason to request a water-side assessment, not to diagnose low refrigerant. Ask the service report to name the heat-pump model, measured differential, table used and resulting flow. The measurement locations matter: a loop's static pressure, a pressure difference across ground piping, and the entering-to-leaving difference across the heat pump are different entries. Ask which one the report contains before comparing it with a unit flow table. A pump that can be heard running is an observation; it is not a documented flow result. A practical record request is: “Please list the entering and leaving water-pressure readings with their units, the measurement locations, the difference, the model-specific table reference and the flow you calculated.” Have the provider record these under the same operating condition. Readings from different visits or operating states do not make a matched comparison. This keeps an unexplained pressure number from becoming an unexplained repair decision. These are questions about the technician's report, not instructions for using test ports. Leave measurements, valves, pump adjustments, loop flushing and fluid changes to the service provider. The manual covers several flow-center configurations; a generic pressure or flow target from another installation is not a substitute for the matching equipment data. If the symptom suggests an air-side problem, record that too Note whether airflow has changed across the house or only in one room. Check an owner-accessible filter according to the equipment instructions and record its condition. WaterFurnace's owner's manual includes filter and thermostat checks among its owner service hints. A photograph of the filter and a description of the affected rooms can help the service company plan the visit. Keep those observations alongside the loop-flow request. You do not have to decide which one is the cause before calling. A useful request is: “Please explain which observations and tests support the repair, and which other causes remain unresolved.” This avoids turning the appointment into an argument over a diagnosis made before measurements exist. Review the proposed repair by circuit and evidence Ask for three short entries on the estimate: the diagnosed problem, the work proposed to correct it, and the check that will show whether the repair succeeded. Keep water-side work and refrigerant-side work in separate line items when both are proposed. This makes it easier to see whether a refrigerant addition is supported or is only an unexplained part of a package. For example, an estimate that names a flow-center repair but also includes refrigerant deserves a follow-up question: “What separate finding requires refrigerant work?” Both tasks may be justified, but the explanation should connect each task to its evidence. You are asking for a clear scope, not choosing a charge amount yourself. If a professional diagnosis confirms refrigerant service, our refrigerant service-scope checklist can help with that later discussion. Apply it alongside the installed heat pump's own refrigerant specification and service documentation. The word “geothermal” does not identify a refrigerant. A short service-call checklist What you have What to request next A fault photo but no diagnosis Send it with the operating mode, time and repeat-event history. A water-side concern with no recorded flow result Request the model-matched flow assessment and its supporting measurements. A report that says only “pump running” Ask what performance evidence supports the conclusion. A pressure number without measurement locations Ask whether it describes static loop pressure or a matched differential across the heat pump. An estimate combining loop work and refrigerant Ask which finding justifies each part and how success will be checked. A complete diagnosis and equipment-specific repair plan Confirm the agreed scope and keep the final service report with the unit records.