Commissioning, Troubleshooting, Maintenance, and Customer Handover
This domain tests commissioning, troubleshooting, maintenance, and customer handover: proving the system works, documenting it, and teaching the owner.
Commissioning
Flush the loop, pressure-test at the specified test pressure, fill with the correct glycol concentration, and purge air. Verify flow, ΔT, pump current, relief-valve setting, expansion-tank precharge, and controller setpoints. Record glycol concentration with a refractometer, pH, pressure, and flow. Confirm tempering-valve output and pool interlock.
Troubleshooting and maintenance
Low ΔT with low flow suggests air, a clogged strainer, or a failing pump. High collector temperature with no pump operation suggests a sensor, controller, or relay fault. Annual service includes glycol testing, pressure check, relief-valve inspection, sensor check, insulation repair, and shading review. Replace glycol per manufacturer intervals.
Handover
Provide manuals, as-built diagram, valve schedule, freeze-protection instructions, warranty terms, and emergency shutdown. Demonstrate controller display and isolation valves. Record serial numbers and commissioning data.
Worked example
A new DHW system delivers lukewarm water. The collector is hot, storage is cool, and the pump runs. The gauge shows 0 gpm. The technician finds a closed isolation valve and air in the loop. After opening the valve and purging, ΔT returns to design.
Traps
Skipping air purge; using a hydrometer instead of a refractometer; not recording glycol; no customer training; failing to check the pool interlock.