What type of hydronic heating system uses diversion (monoflow) tees.

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

Answer: (A)

Monoflow or diversion tees are used to feed radiators off a single main piping run. In a one-pipe hydronic system, the same pipe carries water downstream to multiple radiators. When the water hits a monoflow tee, part of the flow is diverted into the radiator branch, passes through the radiator, and then rejoins the main line downstream for the rest of the circuit. This allows several radiators to be served in sequence without separate supply lines.

Two-pipe systems carry separate supply and return pipes to each radiator, so there’s no need for divergence at a tee. Radiant floor systems use floor loops fed from a manifold, not a single main line with diversion tees, so monoflow tees aren’t part of their typical configuration.