Grundfos TPE3 D Twin-Head Inline Variable Speed Pump

The TPE3 D puts two TPE3 power heads on one in-line pump housing. A flap valve in the common outlet is opened by the flow and stops liquid running back into the idle head, so the pair runs as duty-standby, alternates to share the running hours, or runs both heads in parallel for more flow at the same head. Each head has the Grundfos MLE permanent-magnet motor (IE5) with its own frequency converter and the built-in differential-pressure and temperature sensor, and the pair is controlled without an external controller. The single-head version is the TPE3.

• Alternating operation by time or by energy; the standby head takes over automatically if the duty head stops on an alarm
• Backup operation: one head runs, the other runs briefly each day so it does not seize
• AUTOADAPT (factory setting), FLOWADAPT, proportional and constant pressure, temperature and flow control modes
• Color display control panel on each head, plus Grundfos GO by radio
• Built-in GENIbus; BMS protocols through a CIM module

The table is both heads running in parallel, read from Grundfos’s own dashed parallel-operation curves. With one head running (duty-standby), each model performs exactly like the single-head TPE3 of the same number: its table is on the TPE3 listing and its curve is in this gallery.

TPE3 D 65 — total head in feet, both heads in parallel

Curve ends: 65-80 259 GPM; 65-120 298 GPM; 65-150 329 GPM. Digitized from the published parallel-operation curve in the Grundfos data booklet TPE3, TPE3 D, 60 Hz, North America, p. 82, and rounded down.

TPE3 D 80 — total head in feet, both heads in parallel

Curve ends: 80-40 263 GPM; 80-110 351 GPM; 80-120 394 GPM; 80-150 439 GPM; 80-180 525 GPM. Digitized from the published parallel-operation curve in the Grundfos data booklet TPE3, TPE3 D, 60 Hz, North America, p. 85, and rounded down.

Flows are the points nearest 20%, 50% and 75% of the longest curve in each size, then that curve’s end. Bold = the last column that model’s curve reaches; — = beyond it. Grundfos prints no shut-off figure: 0 GPM is where the curve starts, and the parallel curve reads up to 1 ft above the single-head curve at low flow. PSI = feet ÷ 2.31.

• Flush the pipe system with clean water before first start, without using the pump to do it.
• Fill and vent each head before starting, with the vent screws pointing up.
• The built-in flap valve does the non-return job between the two heads; no separate check valve is needed between them.
• Above 3,280 ft the motors cannot run at full output; check the derating curve in the data booklet.

From Grundfos Installation and Operating Instructions 93076014 and the TPE3 data booklet.

Heating and district heating, air-conditioning, chilled water and district cooling, data center cooling loops and industrial cooling: any circulating loop that needs a standby pump.

From Grundfos Service Kit Catalogue TPE2, TPE2 D, TPE3, TPE3 D (96488862, 12.2023).

The pump is set up and run from its own color control panel, with no app required. Grundfos GO adds guided setup, live operating data, alarm troubleshooting and reports on a smartphone. The panel’s radio button connects the pump to Grundfos GO; Grundfos lists the MI 301 mobile interface as the phone accessory for this. It is sold separately.