Grundfos UPS 50-60/4 F DN50 Flanged Circulator Pump 415V 96403942 #5016

Grundfos UPS 50-60/4 F 280 DN50 Flanged Circulator Pump 415V 96403942

This listing is for a Grundfos UPS 50-60/4 F 280 commercial heating circulator pump, product number 96403942. It is a three-speed, four-pole, glandless wet-rotor circulator with DN50 flanged connections, a 280 mm port-to-port length and a 415V three-phase electrical supply.

Part of the Grundfos UPS Series 200 range, this pump is designed for circulating clean water in commercial heating, cooling and HVAC systems. Its three selectable operating speeds allow the hydraulic performance to be adjusted to suit the installation.

Condition: Supplied in as-new surplus condition. The pump has not been installed or used but may show minor cosmetic markings from storage and handling. Guarantee: Supplied with a 2-year guarantee.

Technical Specifications

• Manufacturer: Grundfos
• Model: UPS 50-60/4 F 280
• Grundfos product number: 96403942
• Product range: UPS Series 200
• Pump type: Single-head glandless wet-rotor circulator
• Motor: Four-pole, three-speed induction motor
• Electrical supply: 3 × 400–415V, 50Hz
• Speed control: Three manually selectable speeds
• Connection size: DN50 inlet / DN50 outlet
• Connection type: DIN flanged
• Flange pressure rating: PN6/10
• Port-to-port length: 280 mm
• Maximum head class:  approximately 5.2 metres nominal
• Speed 1 power input: 130–240 W
• Speed 2 power input: 140–290 W
• Speed 3 power input: 220–430 W
• Speed 1 rated current: 0.43 A
• Speed 2 rated current: 0.50 A
• Speed 3 rated current: 0.92 A
• Liquid temperature, continuous: -10°C to +120°C
• Maximum short-duration liquid temperature: +140°C, subject to operating conditions
• Ambient temperature: 0°C to +40°C
• Pump housing material: Cast iron EN-GJL-250
• Impeller material: Stainless steel EN 1.4301 / AISI 304
• Rotor construction: Canned wet-rotor design
• Mechanical shaft seal: None – glandless construction
• Motor protection: Built-in thermal overload switch; external control requirements depend on terminal-box configuration
• Historical energy classification: Class C
• Net weight: Approximately 23.1 kg
• Gross weight: Approximately 24.4 kg

Performance note: This is a three-speed pump. The actual flow and head depend on the selected speed and system resistance. The 6-metre designation identifies the nominal head class rather than a guaranteed duty point at every flow rate.

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

Technical Documentation

Original Grundfos UPS / UPSD Series 200 technical data booklet, including performance curves, electrical specifications, dimensional drawings and minimum inlet-pressure requirements.

View Grundfos UPS / UPSD Series 200 Technical Data Booklet

Relevant section: Page 28 – UPS 50-60/4 F 280 and UPSD 50-60/4 F 280.

Typical Applications

• Commercial central-heating circulation
• Boiler primary and secondary circuits
• Commercial HVAC systems
• District-heating circulation
• Air-conditioning and cooling-water circulation
• Heating distribution and mixing circuits
• Heat recovery systems
• Replacement of existing DN50 flanged UPS circulators
• Maintaining older 415V three-phase commercial installations

Frequently Asked Questions

What is the Grundfos UPS 50-60/4 F used for?

The Grundfos UPS 50-60/4 F is a commercial wet-rotor circulator designed for moving clean water around heating, cooling and HVAC systems.

It is commonly installed in plant rooms, commercial buildings and larger heating systems where a three-phase circulator is required.

What does UPS 50-60/4 F 280 mean?

• UPS: Grundfos three-speed wet-rotor circulator range.
• 50: Nominal DN50 inlet and outlet connection size.
• 60: Nominal maximum head class of 60 decimetres / approximately 6 metres.
• /4: Four-pole motor version.
• F: Flanged pipe connections.
• 280: Port-to-port installation length of 280 mm.

What is the difference between UPS 50-60/4 and UPS 50-60/2?

The /4 and /2 indicate different motor pole configurations.

The UPS 50-60/4 uses a four-pole motor, operating at a lower rotational speed than the two-pole version. The hydraulic performance curves and electrical characteristics are therefore different.

Although both pumps belong to the DN50 circulator family, they should not be considered interchangeable without checking the required flow, head, electrical supply and dimensions.

What are the three operating speeds and power consumption?

According to the original Grundfos Series 200 data booklet, the 415V three-phase UPS 50-60/4 F has the following electrical characteristics:

• Speed 1: 130–240 W, rated current 0.43 A
• Speed 2: 140–290 W, rated current 0.50 A
• Speed 3: 220–430 W, rated current 0.92 A

Selecting a lower speed reduces the pump's hydraulic performance and can reduce electricity consumption and system noise.

The power figures are electrical input-power ranges taken from the manufacturer's technical documentation.

Why replace this pump with another original UPS circulator?

A significant advantage is the ability to retain an existing 415V three-phase installation.

Many modern high-efficiency circulators use 230V single-phase power. Replacing an older three-phase pump with one of these models may require alterations to the electrical supply, controls, protection equipment and wiring.

This original-style Grundfos UPS also has DN50 PN6/10 flanges and a 280 mm port-to-port length. Modern replacement pumps may have different installation lengths, even when the connection size and nominal head are similar.

Where the existing installation is serviceable, a matching replacement can avoid unnecessary electrical and pipework modifications.

Modern high-efficiency circulators can provide substantial energy savings, so the most suitable option depends on the installation, expected running hours and replacement costs.

What are the minimum inlet-pressure requirements?

Grundfos provides specific minimum inlet-pressure figures for the UPS 50-60/4 F 280 to prevent cavitation and associated pump noise or bearing damage.

The original manufacturer data booklet specifies:

• 75°C liquid temperature: 0.05 bar minimum inlet pressure
• 90°C liquid temperature: 0.15 bar minimum inlet pressure
• 120°C liquid temperature: 1.45 bar minimum inlet pressure

These are minimum pressures required at the pump suction flange during operation.

The required inlet pressure increases significantly at higher temperatures because hot water is more susceptible to cavitation.

When considering a modern replacement, the new pump's minimum inlet-pressure or NPSH requirements should also be checked against the existing system.

What liquid temperature can this pump handle?

Grundfos specifies a continuous liquid temperature range of -10°C to +120°C for the UPS Series 200 range.

Temperatures up to +140°C are permitted for short periods under the manufacturer's specified conditions.

At elevated water temperatures, adequate inlet pressure is essential to prevent cavitation. The applicable system-pressure rating and any installation-specific restrictions must also be observed.

What pressure rating does this pump have?

This pump has PN6/10 flanged connections, suitable for matching DIN flange arrangements.

The permitted system pressure depends on the pressure rating of the installed flange arrangement and connected equipment. The lower-rated component or connection determines the maximum permissible operating pressure.

The PN pressure rating describes the allowable system pressure and should not be confused with the differential head generated by the pump.

What liquids can this pump circulate?

Grundfos specifies the UPS Series 200 range for thin, clean, non-aggressive and non-explosive liquids without solid particles, fibres or mineral oils.

Typical suitable applications include:

• Clean central-heating water
• Commercial heating-system water
• Clean cooling water
• Air-conditioning circulation water
• Compatible closed-loop heating and cooling liquids
• Clean industrial circulation water

Heating-system water quality should meet recognised standards, such as VDI 2035, or equivalent local guidance.

The pump is not intended for sewage, wastewater, abrasive solids, sludge, fibres, mineral oils, diesel, petrol or aggressive chemicals.

Can this pump be used with glycol?

Some Grundfos wet-rotor circulators are suitable for water-glycol mixtures, but compatibility must be checked against the specific pump and liquid.

The glycol type, concentration and operating temperature affect the liquid's viscosity and density. This can change hydraulic performance, electrical loading and the lubrication conditions of the wet-rotor bearings.

Before using this UPS 50-60/4 F with glycol or antifreeze, confirm that the mixture is compatible with the pump materials and operating limits.

Is this suitable for domestic hot-water circulation?

This is the cast-iron housing version of the UPS 50-60/4 F.

For domestic hot-water applications, Grundfos generally specifies pumps with bronze housings to reduce corrosion risk.

This standard cast-iron version should therefore not automatically be selected for potable or domestic hot-water circulation.

Does this pump have a mechanical shaft seal?

No. This is a glandless canned-rotor circulator, meaning the pump and motor form an integrated wet-rotor unit without a conventional mechanical shaft seal.

The pumped liquid lubricates and cools the rotor and bearing assembly. The pump must therefore be correctly filled and vented before operation and must not be run dry.

Does this pump need a control panel?

The UPS 50-60/4 F uses a three-phase electrical supply and incorporates a thermal overload switch.

The required external protection and control arrangement depends on the terminal-box module fitted. Grundfos specifies external contactor arrangements for standard-module installations, while alternative protection and relay modules have different wiring requirements.

The existing installation should be checked before connection, and all electrical work should be completed by a suitably qualified person.

How should this pump be installed?

The pump must be installed with the motor shaft horizontal, regardless of the direction of the surrounding pipework.

The correct flow direction, terminal-box position and access for venting and servicing should be checked before commissioning.

The pump must not be operated dry. Grundfos also advises against operating continuously at very low flow rates, where overheating can occur.

Can this replace a modern Grundfos MAGNA circulator?

The pump may be suitable for replacing an existing circulator with comparable hydraulic performance, but it should not be regarded as a direct replacement based only on nominal DN size or head class.

Modern MAGNA circulators use electronically controlled motors and can have different electrical supplies, installation lengths, control arrangements and performance curves.

A replacement should be selected by checking the required duty point, flange standard, installation length, electrical supply and system controls.

What should I check before ordering?

• Existing pump model and product number
• Electrical supply: 415V three-phase, 50Hz
• DN50 PN6/10 flange compatibility
• 280 mm port-to-port installation length
• Required flow and head duty point
• Existing motor-control and protection arrangements
• Minimum inlet pressure at the operating temperature
• Pumped-liquid compatibility and water quality
• Motor shaft orientation and available installation space

About Our Stock

We specialise in supplying new and unused surplus commercial pumps, circulators and obsolete Grundfos equipment.

This pump is supplied in as-new surplus condition and may show minor cosmetic marks from storage and handling.

Supplied with a 2-year guarantee. Please check the product number, electrical supply, flange dimensions and hydraulic performance before purchasing.