Comparison : Item # R6K, 1-1/2 to 5 British Thermal Units per Hour (Btu/hr) TR Aquefier® Heat Recovery Unit with PC Stop, Relief Valves, and F Freeze Stat
Item # R6K-PC, 1-1/2 to 5 British Thermal Units per Hour (Btu/hr) TR Aquefier® Heat Recovery Unit with F Freeze Stat
Item # R6K-F, 1-1/2 to 5 British Thermal Units per Hour (Btu/hr) TR Aquefier® Heat Recovery Unit with PC Stop and Relief Valves
Item # R6K-PC-F, 1-1/2 to 5 British Thermal Units per Hour (Btu/hr) TR Aquefier® Heat Recovery Unit