Chapter 2
Hydronic
System Piping
One of the main advantages of hydronic
heating is its flexibility. There are a wide variety
of hot water heating systems in operation
today, this section will examine the following
systems:
• Series Loop
• One Pipe
• Two pipe
• Radiant
• Primary-Secondary
It’s important to understand that an individual
home (or building) can have several
different types of systems. For example, there
may be a one pipe system on the main floor,
radiant heat in the basement and a series loop
on the second floor.
Each of these systems would typically be
piped as a separate zone using circulators,
zone valves, manifold telestats and/or solenoid
valves.
Zoning gives the occupants better control of
their comfort and reduces energy consumption
as different temperatures can be maintained in
different areas of the structure.
A series loop (Figure 1) is the simplest and
most common hydronic heating system design.
Each zone is made up of a single run of piping
or radiation and the water flows from the boiler
supply through each heat emitter (finned-tubed
baseboard, cast-iron baseboard) in series and
back to the boilers return. When there are multiple
zones for the project this might be referred
14 National Oilheat Research Alliance
Figure 1