<table cellspacing="0" cellpadding="0" border="0" ><tr><td valign="top" style="font: inherit;">I'm currently modeling a midrise office building with water cooled VAV DX systems (one per floor). These have between three and four compressors that stage on as the building loads. I see input for stages in the PVVT system section but then parallel flow fan powered boxes are not an optional selection. <br><br>Is there a way to use a step function in the DX performance curves? Or am I out of options?<br><br>Thanks,<br>Dug</td></tr></table><br>