I don't know what is causing this, and hopefully someone can shed some light, but when trying to select a "Variable Speed" compressor the option is grayed out for a PSZ?
But, when you follow the subsequent steps you can trick eQuest into making the variable speed compressor option become available.

Change the system to a water source heat pump, assign it to a CW loop, then change it to a PVVT system. The option to change your compressor to Variable Speed is now available, now change it to a PSZ system and you are good to go!

2 questions;
Does anyone see a problem with simulating Variable/Inverter or digital scroll compressors this way? (if so, what is the proper way)
And, is there a quicker way to do this w/o having to change the system type 4 times?

Thanks

Joe Fleming
E.I., LEED AP BD+C, BEMP