Quick Reference Guide

UNT-PRC015-EN 5
General Information on Riser Systems
Hot water, cold water, and condensate risers are factory insulated to avoid condensation and/or
heat loss. Factory insulation is recommended to minimize installation costs and assure quality
control on the insulation application.
Two-pipe and four-pipe riser systems are available. Two-pipe risers provide pipes for hot or chilled
water supply and return only, but not both hot and chilled water simultaneously. Four-pipe risers
provide pipes for hot plus chilled water supply and return simultaneously. Riser systems may be
selected without a condensate riser—not required for a heating-only system. Very tall buildings
may have more than one riser system with each system independent of the other.