I'm in the process of building a water-condensed dual head ducted air-con system.

This is all theory in as much as I have all the parts, some of it brazed together and some of it partially installed.

I have a scroll compressor, which feeds a (quite large) brazed plate heat exchanger as a condenser. From there I go into a LLFD, a large liquid receiver and then a pumpdown solenoid before branching into a couple of EEV's. Because the lines are long, the evaps are reasonably big and the BPHX holds so little liquid, I figured I'd need the receiver to be able to pump down at the end of a cycle. II don't want to leave a lot of static pressure in the evaps/lines while cycled off, and I've always liked the idea of pumping down to obviate the requirement for a sump heater (never gets below about 5 degrees C here)

All my EEV's are rated for bi-di, and I've had thoughts about putting a reversing valve in.

My thinking goes along these lines :

Branch the liquid line around the liquid receiver. Put a check valve in line with the receiver so it only gets liquid in a cooling cycle, and put an additional EEV with opposing check valve across the receiver.

The theory being that at the end of the heat cycle, I can flip the reversing valve, close the liquid line solenoid and pump it down.

I've never dismantled a VRV heat pump before, so I'm coming from a perspective of barely knowing enough to be dangerous. I'm almost content to leave it as a cool only system (and I'm basically convinced it will work), but I've got this lovely reversing valve and 1/2" EEV here begging to be used.

The FCU's are pretty standard, so I figure if the whole thing is a failure I can just install a couple of small split compressor/condenser units and be done with it.

Questions, explanations, advice or smacks around the head are most welcome.