What is primary and secondary piping?

Primary/ secondary piping is a versatile piping method that’s increasingly being used as the backbone of modern multi-load/multi-temperature hydronic systems. The result is an extremely versatile piping method that’s increasingly being used as the backbone of modern multi-load/multi-temperature hydronic systems.

What is a primary pipe?

The primary piping elements include steel pipes, connecting elements (flanges, pipe bends, pipe elbows, tees), stop and shut-off-and-regulating valves (slide gates and valves), drain devices, expansion joints, supporting structures and parts, hangers and fastening elements, thermal insulation.

What is a boiler primary loop?

Primary Loop Piping is commonly used in boiler heating systems that run needing multiple temperatures or contstant temperature at the hydronic boiler is required. Primary Loop Piping allows non condensing boilers to maintain a heat level in the boiler high enough to allow the boiler to run at its most efficient state.

What is the maximum spacing recommended for the closely spaced tees on a primary secondary system?

It is VERY important that the closely spaced tees be no further apart than 4 times the diameter of whatever size pipe constitutes the primary/secondary loop, and it is equally important that the length of the straight pipes extending from the closely spaced tees be at least 6 times that same pipe diameter.

How does primary secondary piping work?

When the flow of cooler water returns from the secondary circuit, the hot primary water, which jumped the “gap” between the two tees mixes with the return water. The hotter water instantly raises the returning water’s temperature and protects the boiler from flue-gas condensation and thermal shock.

What is the difference between primary and secondary pumps?

The primary loop uses a constant speed pump to circulate the working fluid (water). The secondary loop uses a variable speed pump to manipulate the flow of the fluid such that the cooling coil demand is satisfied.

What is a secondary loop?

“A secondary loop refrigeration system incorporates two different refrigerants to provide cooling. In all systems, the primary loop is a traditional direct expansion design that uses a phase change refrigerant such as R-404A and a compressor to circulate the refrigerant.

What is primary flow and return?

With an indirect water system, the copper hot water cylinder contains a coil of pipe. This heating is called the “primary” circuit, the pipes running to and from the boiler are called the primary flow and return. The hot water tank operates in exactly the same way as the direct system.

What is Reverse return piping?

Reverse return piping is designed such that the path through any load is the same length and therefore has approximately the same fluid pressure drop. Reverse return piping is inherently self-balancing. It also requires more piping and consequently is more expensive.

What is a primary secondary system?

The primary loop uses a constant speed pump to circulate the working fluid (water). The secondary loop uses a variable speed pump to manipulate the flow of the fluid such that the cooling coil demand is satisfied. The above mentioned pumps are considered as a primary/secondary pumping pair.

What is a secondary pump?

A separate secondary pump delivers variable flow to the secondary loop and two-way valves are applied to control flow through each zone. It also decreases the complexity of the chiller or boiler staging and control by eliminating on/off valves and min/max flow requirements.

What is primary secondary piping for boilers?

Primary-secondary pumping lets you use small, inline circulators – even on large commercial jobs – and that’s a real plus. And in a multiple-boiler system, this simple method of piping gives you a way to lower boiler standby losses and save fuel.

What is primary secondary piping in a hydronic system?

Primary Secondary (P-S) hydronic piping is a common piping scheme in today’s hydronic heating and cooling systems. This short series of blogs will provide examples of piping schemes which will support the reduction of hot water return temperatures to enhance the value of condensing boilers.

Which is primary or secondary piping for a condensing boiler?

Primary/Secondary Piping For Condensing Boilers (Multiple) Monday, December 01, 2014 Modern Hydronic Designs For Condensing Boilers 10 Equal Flow Distribution • Boiler GPM = System GPM • Very little mixing • Equal system/boiler supply and return temperatures • This is situation is idealfor a condensing boiler • Very difficult to achieve in practice

What are the basics of primary secondary pumping?

PRIMARY-SECONDARY BASICS Primary-secondary pumping and control circuits are simple in theory and practice. Operation is based on this simple rule: WHEN TWO PIPING CIRCUITS ARE INTER-CONNECTED, FLOW IN ONE WILL CAUSE FLOW IN THE OTHER, T0 A DEGREE DEPENDING UPON THE PRESSURE DROP IN THE PIPING COMMON T0 BOTH.

What are the different types of chilled water piping systems?

Chillers CHW Pumps Bypass Valve 2 Chilled Water Piping System Types (typical) Configuration Load Valves Installed Cost Pumping Cost Constant Primary Flow 3-way Lowest Highest 3 Primary / Secondary 2-way Highest Medium Variable Primary Flow 2-way Medium Lowest Secondary Pumps Load = Flow X DeltaT Load Equation 4 Secondary Pumps