ARXA24GALH / ARXD12GALH / ARXD18GALH - EEV Closed on Delivery

This article summarises a factory investigation into indoor units where installers found that pressure would not pass through the indoor unit piping during commissioning because the electronic expansion valve (EEV) was closed.

Key finding: The affected units were believed to have been shipped with the EEV at 0 pulses (fully closed) because power was removed before the factory F-mode reset process had finished.

Applies To

ModelReported Unit Reference
ARXA24GALHR000182
ARXD12GALHR001383
ARXD18GALHR001077

Problem Detail

  • During commissioning, installers pressurised the refrigerant piping and found that pressure did not return to the outdoor unit connections.
  • The indoor flare connections were disconnected and pressure was applied through the suction side, but pressure still did not pass through the indoor unit.
  • The concern was whether the indoor unit EEV could be supplied in a closed position.

Factory Process Investigation

The factory confirmed the normal end-of-line process used after operational and noise testing.

  1. After testing each operating mode, the indoor unit is returned to the factory default condition using F-mode.
  2. When F-mode is completed correctly, the EEV position becomes 800 pulses.
  3. At the completion of F-mode, the operation lamp turns off.
  4. The unit must remain powered until F-mode has completely finished and the operation lamp has turned off.
  5. If power is removed before F-mode finishes, the EEV position can remain at 0 pulses (closed).
Normal factory condition: EEV = 800 pulses after successful completion of F-mode.
Affected condition: EEV = 0 pulses if power is removed before F-mode completes.

Root Cause

The factory concluded that the likely cause was that the power supply cable had been removed before F-mode had finished. This left the EEV fully closed when the indoor unit was shipped.

The factory also found that the requirement to keep the product powered until F-mode had finished had previously been communicated verbally by the line administrator, but it had not been included in the written work instruction. Factory operators were also not aware of the consequence of removing power too early.

Factory Countermeasure

  • The requirement to maintain power until F-mode is fully completed was added to the factory work instruction from 20 August 2014.
  • Factory operators were retrained on the correct procedure.
  • Training included an explanation of what can occur if power is removed before F-mode is complete.

Product Action

Product StatusAction
Already installed productTake corrective action at the individual site if the problem occurs.
Stock productNo specific stock action was identified in the report.
Manufactured productFactory countermeasure already implemented.

Service / Commissioning Guidance

If pressure will not pass through the indoor unit during commissioning: Do not immediately assume there is a blocked pipe or damaged EEV. An affected unit may have been supplied with the EEV in the fully closed position.
  • Confirm the model is one of the affected series listed above.
  • Consider the possibility that the EEV is at 0 pulses / closed.
  • Power and operate the indoor unit as required so the EEV can be driven from the closed shipping condition.
  • Repeat the pressure / flow check after confirming EEV operation.
  • If the EEV still does not respond, continue normal diagnostics for the EEV, wiring and indoor PCB.