Low side pressure ranging from 15psig-125psig on multi zone AC system????

[Jet]

Hey everyone. I'm having an issue with a multi-zone ducted AC system. It was running normally for a few months after installation and recently started shutting off on LOW PRESSURE PROTECTION. It is an R410 inverter Airlux unit which I believe is one of GREE's units. I've observed the system run at pressures of 260/80 at 70 ambient. Then after 10 minutes or so the low side starts dropping all the way to 15 or so, runs for a while and rises up to 125, runs for a while and drops to 15 the same way. Throughout this whole time, the unit works and cools with a delta of 25. At times, the system shuts down on a LOW PRESSURE PROTECTION error.

If anyone has any thoughts on what may be happening with this system and/or what can be done. I would greatly appreciate it.

[install monkey]

crap in the pipework or moisture