What is a single pipe system?

This is why it is called a "one-pipe" system.

There are two main types of pipe systems: one pipe and two pipe. A one-pipe heating system has all radiators connected to one pipe. This acts as both a flow pipe and a return pipe. The temperature drops along the pipe.

How do single-pipe radiators work in the same way? One-pipe steam installations use steam to flow from the boiler to radiators. There, it displaces cold air by pushing it through a radiator vent. When the radiator has reached its full steam, the air vent automatically closes. The condensate flows through the same pipe again.

You may also wonder, "What is a single-pipe heating system?"

One-pipe central heating systems operate through a single-feed hot water supply pipe. This pipe comes from the boiler that supplies hot water to each radiator. Each radiator is supplied with hot water via a smaller supply pipe that branches off the main pipe.

Is it important which pipe goes where on the radiator?

When fitting radiators, should TRV's be on the return or flow pipe? Steve Harris, Wavin's technical services engineer, answered the question. Although most TRV's can be fitted to either flow or return pipe, it is best to do so on the flow side.