Entering pipe length data adjusts the VRF outdoor unit capacity according to the piping correction curve that is part of the Performance curve set.
The equivalent piping length is the length of piping between the outdoor unit and the farthest indoor unit. The level difference is the maximum height difference between the outdoor unit and the highest or lowest indoor unit.
By default, piping correction values for cooling and heating are the same. Editing either cooling or heating will update the other to match. To enter different piping lengths or height differences for cooling and heating, check the “Separate heating & cooling values” check box.
For example, suppose the building has an indoor unit serving a core zone full of equipment that is always generating heat or that is simply located very deep within the building and thus will never need heating. This indoor will operate only in cooling mode. If this indoor unit is significantly further from the outdoor unit or has a greater height difference relative to the outdoor unit, as compared to any of the indoor units that will provide heating, then the Equivalent piping length or Level difference inputs may be greater for cooling than for heating.
