Hydronics

Hydronics is the side of the building that moves heat with water. A pump pushes hot or chilled water out through piping to a coil or terminal unit at every zone, a control valve at each load meters how much heat that load takes, and the water gives up its heat and returns for another pass. Every station on that loop is something a control system sizes, meters, or balances — the pump head and speed, the valve Cv and authority, the flow each load needs, the temperature split the plant sees. These pages walk the water side from the loop architecture out to the coil, and give you the tools that put a number on each station.

New to it? Work the five lessons in order — they build from the loop types out through load piping, pump control, and balancing, then close on where the design flow comes from. Already have a system in front of you? Jump to the tools: size a control valve, check that it will actually control, work the waterside flow, or predict what a speed change does to a pump. Everything here is open, needs no login, and tracks nothing.

Start here — the lessons, in order

1 Hydronic Loops → 2 Load Piping → 3 Pump Control → 4 Balancing → 5 Coil Selection

LESSON :: HYDRONIC LOOPS READ

Hydronic Loops

How a building distributes its water — direct versus reverse return, and primary-secondary with the injection tee — and what each loop choice does to flow and control. The chapter's starting point.

Step 1Loop TypesPrimary–Secondary

LESSON :: LOAD PIPING READ

Load Piping

How each load ties into the loop — a two-way valve for variable system flow versus a three-way for constant — and how that one choice at the coil ripples back through the whole system.

Step 22-Way vs 3-WayVariable Flow

LESSON :: PUMP CONTROL READ

Pump Control

Moving the water — the pump curve and the operating point, variable-speed (VFD) control against a differential-pressure sensor, and the DP-setpoint reset that saves pump energy.

Step 3Pump CurveDP Reset

LESSON :: BALANCING READ

Hydronic Balancing

Getting design flow to every load — calibrated balancing valves and PICVs, the proportional field method, and how to tell when a loop is starved at the far end or overflowing near the pump.

Step 4CBV · PICVDesign Flow

LESSON :: COIL SELECTION READ

Coil Selection

Where the design flow a balancer chases actually comes from — the load-to-flow chain, why the chosen temperature split sets the GPM, and how a coil is picked to meet the capacity at its entering conditions.

Step 5Load → ΔT → GPMEntering Conditions

Build one — the simulator

One interactive model for the water side — assemble a loop and watch it solve, so the loop types and pump behavior from the lessons move in front of you instead of sitting on the page.

SIM :: LOOP BUILDER RUN

Hydronic Loop Builder

Drop a plant, pump, coils, and valves on two elevations, pipe them together in 3D, and watch flow and water temperature solve live — a sandbox for the loop architectures the lessons cover.

SandboxLoop BuilderLive Solve

The tools

Four field utilities for the water side — size a control valve and check that it will actually control, work the flow a load needs, and predict what a speed change does to a pump. No login, nothing to install.