Tell it your design flow and hose size. It tells you which loop tier you're in — and whether you need a reservoir — then builds your grocery list with every fitting, coupler, and clamp in one consistent size. No mixed-size surprises at assembly time.
Tier 1 — Tankless (100 L/min and under). No tank. A fill tee at the high point handles fill, venting, and expansion. Most first loops live here — simpler, cheaper, fewer leak paths.
Tier 2 — Tank loop (over 100 L/min). A reservoir is required: fill volume, expansion room, deaeration, and a calm pump inlet stop being optional. And past ~125 L/min the tank must be baffled — an open tank vortexes and entrains air faster than it can separate, so a baffle plate and inlet diffuser give the coolant residence time to shed air before the pump inlet.
Keep the tank-to-pump line level and straight. Gravity head in a sloped or stepped suction run adds (or subtracts) pressure the pump never made, and skews your measurements. As horizontal to gravity and as straight as the bench allows.
Pressure sensor: as close to the pump as possible. Every foot of line between the pump outlet and the sensor hides line loss inside your pump reading.
Flow meter: anywhere on the discharge line. It reads the same wherever it sits on discharge — just respect its straight-run requirement.
Backpressure is set by hand. A manual valve on the discharge line is your operating-point adjustment: open or close it to move where the pump rides on its curve. It's in the grocery list below.
| Item | Spec | Qty | Buy |
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Buy links open a supplier search for the exact size class — Grainger first, then Zoro, Global Industrial, Amazon, MSC. Some are affiliate links at no cost to you (see the disclosure below). Confirm thread, material, and pressure rating against your pump and load ports before ordering. For the pump itself, run the pump sizing calculator first.