Grundfos TPD 50-30/4 A-F-A-BUBE circulator Pump 96408857 415v #2628

GRUNDFOS TPD 50-30/4 A-F-A-BUBE – 415V Twin In-Line Circulator Pump (96408857) #2628

This listing is for a Grundfos TPD pump from the TP family of dry-rotor, single-stage in-line circulators. The TPD is the twin-head version, providing duty/standby flexibility or parallel operation using identical in-line suction and discharge ports. It is designed for heating, cooling and industrial circulation duties where serviceability and continuity of operation are important.

The pump uses the top-pull-out design, meaning each power head (motor, pump head and impeller) can be removed for maintenance while the pump housing remains in the pipework.

Condition: supplied as surplus / unused stock. The unit may show cosmetic marks consistent with storage and handling. It is inspected prior to dispatch and confirmed free-turning and operational.
Guarantee: supplied with our 2-year guarantee.

• Pump type: TPD twin dry-rotor in-line circulator
• Control: fixed-speed operation
• Connection: DN50 DIN flanges (PN6 / PN10)
• Port-to-port length: 280 mm
• Service design: Top-pull-out – power head removable without disturbing pipework
• Shaft seal: BUBE mechanical seal

Need help confirming suitability?
Call us on 01803 220416 for technical advice.

Manufacturer product page

Full technical specifications, curves and documentation can be viewed on the official Grundfos product page:
View Grundfos TPD 50-30/4 (96408857) – Variant details

Key specifications (summary)

• Model: TPD 50-30/4 A-F-A-BUBE
• Grundfos product number: 96408857
• Rated motor output (P2): 0.37 kW (nominal)
• Electrical supply: 3 × 220–240 V Δ / 380–415 V Y, 50 Hz (listed as 415 V)
• Connection: DN50, PN6 / PN10 DIN flanges
• Port-to-port length: 280 mm
• Shaft seal: BUBE

Typical applications

• Heating systems and boiler circuits
• District heating and district cooling
• Air-conditioning and chilled water systems
• Industrial circulation loops
• Building services requiring duty/standby redundancy

Frequently Asked Questions

What does the model number mean?

• TPD – twin-head TP in-line circulator
• 50 – nominal diameter of inlet and outlet ports (DN50)
• 30 – head series designation
• /4 – 4-pole motor
• A – basic version
• F – DIN flange connections
• A – basic version
• BUBE – shaft seal code

What does the BUBE shaft seal code mean?

• B – rubber bellows seal construction
• U – tungsten carbide seal face
• B – carbon, plastic-impregnated counterface
• E – EPDM elastomers

Seal operating temperature (BUBE): suitable from 0 °C up to 120 °C in water duties (EPDM-limited).

Why choose the BUBE seal?

The BUBE seal uses a tungsten carbide against carbon-impregnated graphite face pairing. This combination provides the wear resistance of tungsten carbide together with the self-lubricating, low-noise properties of carbon, offering good hot-water behaviour and improved tolerance to brief dry running compared with hard/hard pairings. It is a proven and reliable choice for general HVAC circulation duties.

What liquids can this pump be used with?

This twin pump is typically suitable for clean circulation liquids compatible with EPDM, such as:

• Heating system water meeting accepted water quality standards
• Cooling and chilled water circuits (above 0 °C)
• District heating water
• Condensate
• Softened water
• Clean industrial circulation liquids compatible with EPDM

Not suitable for:

• Liquids containing solid particles or fibres
• Flammable liquids
• Mineral oils or synthetic oils
• Strong chemicals or solvents that attack EPDM
• Sea water or aggressive saline solutions

Can one head be used as standby?

Yes – the TPD twin configuration allows duty/standby or parallel operation, but this requires an external control system. Automatic changeover and alternation are not managed by the pump itself; they must be provided by a separate control panel, inverter drive system, or BMS controller configured for twin-pump operation.

Is this suitable to replace other DN50 circulators?

This model uses DN50 PN6 / PN10 DIN flanges with a port-to-port length of 280 mm. Where dimensions match, it can replace other DN50 in-line circulators from manufacturers such as Wilo, Lowara and KSB, subject to hydraulic duty and system requirements.

Can the motor be removed without draining the system?

Yes – each head uses a top-pull-out design, so the power head can be removed while the pump housing remains installed in the pipework.

About Our Stock

Stock code: #2628
We specialise in supplying quality pumps and equipment. This unit is supplied as surplus stock, inspected prior to dispatch and supplied with a 2-year guarantee.