Diversion tees (monoflow) are used in which hydronic system configuration?

• A. One pipe system
• B. Two pipe system
• C. Three pipe system
• D. Radiant system

Answer: (A)

Diversion tees are used in a one-pipe hydronic system. In this setup, all radiators are fed from a single continuous pipe, so the flow would otherwise travel mainly through the path of least resistance and skip some radiators. The monoflow/diversion tee provides a side branch that diverts a portion of the hot water into the radiator while the rest continues along the main pipe. The radiator’s temperature is controlled by adjusting the branch flow, helping to balance heat output along the loop. This approach isn’t used in two-pipe systems (which have separate supply and return lines) or radiant systems (which typically use dedicated loops or manifolds), where such diversion in a single pipe isn’t how heat is distributed.