03/09/2026
This one was a proper engineering job!
Our engineers have been carrying out remedial works to the DX side of an AHU serving a hospital department, working across two refrigeration circuits.
The job included recovering the existing refrigerant, relocating electrical and control panels to make future servicing easier, replacing drier cores, rerouting pipework and cabling, pressure testing both circuits and recharging the systems with new R407C refrigerant.
Once the system was ready, it was time for commissioning — and that's where the real fault-finding began.
Both circuits developed the same problem, with the compressors running the suction pressures continued to drop.
Our engineers worked through the system methodically, checking the electronic expansion valves, control equipment, pressure sensors, pump-down solenoids and refrigerant flow.
The investigation has pointed towards the existing EVD4 control drivers, which date back to 2009 and are now obsolete. Further specialist investigation or replacement of the drivers will be required before commissioning can be completed.
Not every fault gives up its secrets straight away! 🔧
But that's exactly where good engineering and systematic fault-finding come into their own — identifying the problem, testing the possibilities and leaving a clear route forward.
