ARTG45LHTA - Distributor Freezing Due to Foreign Contamination
This article summarises a factory quality investigation into ARTG45LHTA indoor units where freezing occurred at the refrigerant distributor. Inspection found foreign material inside the distributor, identified as insulation material.
Key finding: Foreign insulation material was found inside the distributor. The material could restrict refrigerant flow and cause localised freezing at the distributor.
Applies To
| Product | ARTG45LHTA |
| Reported quantity | 2 units |
| Known serial number | T008921 |
| Reported fault | Freezing at refrigerant distributor |
Problem Detail
- Freezing was reported at the indoor unit refrigerant distributor.
- The attending technician found foreign contamination inside the distributor.
- Two units were reported, including serial number T008921. The second serial number was not recorded in the source report.
Analysis Result
Returned Part Analysis
- The foreign material found inside the distributor was identified as insulation material.
- A similar issue had previously been reported in the Australian market under reference GS13-224.
- In the previous case, the foreign contamination was also identified as insulation material.
- The exact mechanism by which the insulation entered the distributor was not confirmed in the earlier investigation.
- A process-validation countermeasure had already been introduced from 27 December 2013.
- The affected ARTG45LHTA unit in this report had been manufactured before that countermeasure was implemented.
Important: The contamination found in this case was the same type of insulation material identified in the earlier Australian-market case.
Distributor Manufacturer Investigation
The distributor manufacturing process at OKAYAMA was reviewed.
- The distributor manufacturer does not use the insulation material identified as the contamination.
- The distributor was confirmed as being manufactured in accordance with the applicable production standards.
FGT Manufacturing Record Review
- No repair history was recorded for the affected product.
- The indoor heat exchanger assembly manufacturing process was reviewed to identify where foreign material could potentially enter the refrigerant circuit.
Heat Exchanger Manufacturing Process
| Step | Manufacturing Process |
|---|---|
| 1 | Fit coupling pipe assembly |
| 2 | Weld coupling pipe assembly |
| 3 | Fit distributor assembly |
| 4 | Weld distributor assembly |
| 5 | Remove flare nut and fit coupler |
| 6 | Vacuuming |
| 7 | Charge helium gas at 1.2 ± 0.2 MPa |
| 8 | Leak check |
| 9 | Confirm residual pressure using helium gas |
| 10 | Apply INS (PIPE) B / 14B |
| 11 | Apply Seal (PIPE) A / B |
| 12 | Remove coupler |
| 13 | Check for foreign contamination |
| 14 | Visual inspection |
| 15 | Fit flare nut at 70 ± 10 kgf.cm |
Suspected Entry Point
The source report notes that Seal (PIPE) A / B is made from the same material as the foreign contamination. However, this material was considered too large to be inserted through the half union in its normal form.
Factory speculation: The most likely point where the foreign material could have entered the refrigerant circuit was at the half union during the FGT manufacturing process. The contamination may then have moved through the refrigerant circuit and lodged in the distributor.
The source report presents this as a possible cause; it does not confirm exactly how the insulation material entered the system.
Factory Countermeasure
- A dedicated foreign-contamination check was added to the process validation.
- This process was implemented from 27 December 2013.
- The affected unit in this report had been manufactured before implementation of this countermeasure.
Product Action
| Product Status | Action |
|---|---|
| Already installed product | Take corrective action at the individual site if the problem occurs. |
| Stock product | No specific action. The factory considered recurrence unlikely. |
| Manufactured product | Factory countermeasure already implemented. |
Service Guidance
- If an ARTG45LHTA shows localised freezing at the distributor, consider a restriction within the distributor or refrigerant circuit.
- Where practical, inspect for evidence of foreign material or insulation contamination.
- Do not assume the symptom is caused only by refrigerant charge, airflow or an EEV issue; internal contamination is a documented possible cause on units manufactured before the countermeasure.
- If contamination is confirmed, affected components should be replaced and the refrigerant circuit checked for remaining foreign material before recommissioning.