It cannot be overstated the importance of a properly designed hot water distribution system. The heat transfer media (fill) cannot achieve full performance without proper coverage. In many cases tuning the distribution system is the most cost effective way to improve performance. In most cases very little time is given to the design and an off the shelf or standard one size fits all approach is used. Obviously fan performance is important along with a proven pressure drop thermal design. We can review your distribution system and determine if it can be improved. We have had decades of experience in improving performance thru enhancing distribution system designs.