What happens
The valve or its refrigerant path cannot deliver the expected flow despite a valid actuation circuit.
Typical symptoms
Persistent starved-zone behavior or unstable feed with plausible inputs and verified commands.
Checks that distinguish this cause
Verify charge, liquid supply and sensor plausibility first. Compare zone and piping temperatures under the model test condition while following the approved valve diagnostic sequence; do not force arbitrary valve positions.
What can look similar
A kinked line, closed service valve or insufficient charge can look like a restricted EEV.
Repair direction
Correct the established restriction or replace the confirmed valve using the approved sealed-circuit procedure.
Verify the repair
Verify flow response and stable operation in each permitted mode.
Equipment-specific limits
A commanded step count is not proof of actual valve position. Coil pinouts, drive signals, initialization and resistance limits depend on the installed assembly.
Practice this diagnosis
This cause is a reference topic; it does not yet have a dedicated simulated call. Browse the practice board.
References and applicability
Original HVACSim explanations with manufacturer and instrument-maker references for further reading. These resources support the subject; their model-specific examples are not specifications for every system.
- Daikin: 17 Series service manualModel-specific sensor and control examples; terminal values and code definitions vary.
- Senville: R-454B model documentationSeparate installation and service documents for indoor styles and multi-zone generations.
Editorial review: 2026-09-29. Verify the current manual for the installed model.