Hot gas defrost query

Q With long suction lines, will there be problems using hot gas defrost? I'm working on a rack system with about a 100-foot suction line that is using R-22.

A I would stay on the other side of the “75/25 relationship.” That is, 75 percent of the Btu should be in circulation and defrost 25 percent. Chances are if you go outside of those boundaries you will not get defrost. Defrost load sometimes is two and a half to three times the Btu requirement of the refrigeration load.

Question from Grantley Noel Parris, St. Michael , Barbados . Answer by Steve