What an HIU service includes
A proper HIU service is a performance test, not a visual inspection. We isolate the unit, strip and clean the primary and secondary strainers, then measure flow and return temperatures on both sides of the plate heat exchangers under a real draw-off. Those four readings tell us whether the DHW exchanger is fouled, whether the control valve is actually closing, and whether the unit is returning water cool enough for the network. Every reading is written down so degradation is visible year on year.
- Primary and secondary strainer clean
- DHW and heating plate heat exchanger performance test
- Control valve, actuator and sensor operation check
- Differential pressure control valve verification
- Safety and pressure relief checks
- Filling loop, isolation valve and leak inspection
