A one pipe system or monoflo system as it is sometimes called is a distribution system that uses specialized tee fittings to divert a portion of the hot water through a branch piping path.
Hot water heating coil piping diagram.
If a manual or automatic control valve is placed in the branch piping path the water flow through a given heat emitter can be fully controlled.
All ball isolation valves are furnished with an adjustable memory stop feature and may be used as a balancing valve.
Heat is released from the water as it flows through the heating unit coil terminal.
When ordered unions are installed at the water coil and are available on vav products and all fan coil units except vh.
For hot water coils control valves are available normally open.
There is no separate header tank and heating coil inside the hwc as in modern systems.
The garn unit all related heating equipment including pumps piping fan coils hot water baseboard radiant floor heating systems etc and all electrical equipment including power wiring controls control wiring back up electric heating etc must be installed by a qualified installer or competent licensed personnel in strict compliance.
After heat is released the water returns to the boiler to be reheated and recirculated.
This is a diagram of the obsolete one pipe pumped system.