23 Mar 2022

The customer commissioned a Daikin VRV Heat Recovery System and the HVAC worked for ~2 years. The customer was satisfied with the HVAC.

Customer Challenge

After ~2 years, both the inverter compressors were faulty; a rare case where both are. The customer decided to switch the service company for the replacement. The compressors were replaced and activated but the root cause was still unknown.

The traditional course of action

  • Schedule a site visit
  • Travel to site
  • Connect a service tool and collect a current limited operational data
  • Analyze the collected data
  • Find the fault and fix it
  • Collect new data and verify the fix

Remote service course of action

The control swap was probably the major factor in the compressor fault

The service team performed a checkup using the CoolAutomation Remote Diagnostics solution and found irregular readings. When both inverter compressors units were heating- both were heating as required. But when one unit was in Heat mode and the other was Off, the unit in Heat mode was cooling. 

Bu using CoolAutomation's Remote Diagnostics solution, the VRV expert gained remote access to the site's data. Based on the data, he suspected a swap of control lines between the two units (in this case: AV and Bedroom 1). A team of junior service providers was sent to the site. Upon arrival at the site, they opened the ceiling and indeed the control lines were swapped between the units.

After fixing the issue technically, the team used CoolAutomation's Remote Diagnostics solution again. They repeated the operational sequence and saw that now both units were working correctly. And so the root cause was reaffirmed: the control swap was probably the major factor in the compressor fault and liquid refrigerant may have entered the suction pipe.

Course of action

  • Access the system remotely to test the system and find fault: AV Room & Bed 1 have crossed F1-F2 BS-indoor cables
  • Send a junior VRV engineer for 1-hour on-site to perform a fix
  • Verify the fix remotely: After correcting cross cables, Bed1 is in Heat mode ( Although the AV rack unit is off) The technician can remotely set and run an automatic test procedure on the fixed system followed by remote verification that all works as expected.