Grundfos STN-2.0 Twin Brass Shower Negative Pump | 98284259

• Negative head shower pump - for gravity-fed systems where the outlet sits below the cold water tank
• 2.0 bar rated pressure boost - up to 20 m maximum head
• Twin brass impellers with regenerative impeller design for reliable performance
• WRAS approved - certified safe for use with drinking water systems
• 510 W rated power input - rated current 2.2 A at 230 V / 50 Hz
• Flow rate up to 50 litres per minute
• Built-in thermal motor protection - pump stops automatically if it overheats
• IPX2 enclosure rating with anti-vibration feet fitted as standard
• Noise level 55-65 dBA at 1 metre
• Supplied with four flexible stainless steel braided connection hoses
• Manufacturer warranty: 2 years
• Dimensions: 287 x 309 x 232 mm

Grundfos STN-2.0 B Twin Brass Negative Head Shower Pump

Purpose-built for gravity-fed systems:

The Grundfos STN-2.0 B (Product No. 98284259) is a negative head shower pump designed specifically for gravity-fed hot water systems where the shower outlet is positioned below the cold water storage tank. It is the correct replacement for any existing 3 bar negative pump - identifiable by the presence of air tanks attached to the existing unit - and suits homes where low mains pressure results in a disappointing shower experience.

Regenerative impeller design:

The STN-2.0 B uses a regenerative impeller design with twin brass impellers to deliver consistent pressure across the full plumbing route. Unlike standard centrifugal pumps, the regenerative type is equipped to overcome air pockets and maintains performance even where the pipework includes multiple bends or elbows. The rated pressure is 2.0 bar, with a maximum head of 20 m and a minimum static head requirement of just 1 m.

Durable brass construction with built-in protection:

The pump housing and both impellers are manufactured in brass, contributing to long-term durability in a wet environment. A built-in thermal protection system monitors the motor continuously and stops the pump immediately if it reaches an unsafe operating temperature. Silicon carbide seals support quiet, long-life operation, and the anti-vibration feet fitted as standard reduce transmitted noise to floors and pipework.

WRAS approved and CE certified:

The STN-2.0 B carries both CE certification and WRAS approval (Water Regulations Advisory Scheme, approval number 1209052), confirming it has passed independent testing for use with potable water systems. It conforms to ISO 9906:2012 3B, Model A curve tolerance standards. The pump activates via a flow switch - no pressure switch is fitted - which is the correct configuration for negative head installations. G ¾ inch push-fit connections are used at both inlet and outlet, accepting standard 22 mm flexible hoses.

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Key Features

Negative Head Configuration - flow-switch activation only, correct for gravity-fed systems where the outlet is below the cold water tank.
Regenerative Impeller Design - twin brass impellers overcome air pockets and maintain pressure through complex pipework routes.
2.0 Bar Rated Pressure - maximum head of 20 m, rated head 15.1 m, suitable for single or multiple shower outlets.
WRAS Approved - approval number 1209052, certified safe for potable water systems in the UK and Ireland.
Built-in Thermal Motor Protection - stops the pump automatically if the motor temperature exceeds safe limits.
IPX2 Enclosure Class - rated for the damp environments typical of airing cupboards and hot press installations.
Anti-Vibration Feet - fitted as standard to reduce noise transmission through floors and pipework.
Silicon Carbide Seals - long-life shaft seals for quiet, reliable continuous-duty operation.
22 mm Push-Fit Connections - G ¾ inch inlet and outlet with PN 6 pressure rating, compatible with standard flexible hose fittings.
Stainless Steel Braided Hoses Included - four flexible, corrosion-resistant connection hoses supplied in the box.

Specifications

• Model: Grundfos STN-2.0 B GBQP (Product No. 98284259)
• Pump type: Regenerative, twin impeller
• Impeller material: Brass
• Head configuration: Negative head only
• Rated pressure: 2.0 bar
• Maximum head: 20 m
• Rated head: 15.1 m
• Minimum static head: 1 m
• Maximum flow rate: 50 litres/min (0.6 m³/h)
• Minimum flow rate: 5 litres/min
• Power input (P1 max): 510 W
• Rated voltage: 230 V / 50 Hz
• Rated current: 2.2 A
• Cable length: 1.5 m
• Motor type: Induction
• Enclosure class: IPX2 (IEC 34-5)
• Insulation class: F (IEC 85)
• Liquid temperature range: 5-60 °C
• Ambient temperature range: 0-40 °C
• Maximum operating pressure: 6 bar
• Noise level: 55-65 dBA at 1 m
• Inlet/outlet connections: G ¾ inch push-fit (PN 6)
• Activation: Flow switch (no pressure switch)
• Certifications: CE, WRAS (approval no. 1209052)
• Standard: ISO 9906:2012 3B, Model A
• Colour: Black
• Net weight: 9.5 kg
• Dimensions (HxWxD): 287 x 309 x 232 mm
• Manufacturer warranty: 2 years

What's Included in the Box

• Grundfos STN-2.0 B negative head shower pump
• 4 x flexible stainless steel braided connection hoses (22 mm push-fit)

Setup and Care

Installation guidance:

The STN-2.0 B is designed for gravity-fed hot water systems where the shower outlet is positioned below the cold water storage tank - confirmed by the presence of air tanks on any existing pump. G ¾ inch push-fit connections at both inlet and outlet accept the supplied 22 mm stainless steel braided hoses. Installation by a qualified plumber is recommended to ensure correct orientation and comply with local water regulations.

Positioning and ventilation:

The pump should be installed in a dry, well-ventilated location such as an airing cupboard or hot press, with the anti-vibration feet resting on a firm, level surface. Keep the area around the pump clear to allow adequate airflow to the motor. The IPX2 enclosure rating means the pump is splash-resistant but should not be installed in direct contact with water.

Routine maintenance:

Inspect the stainless steel braided hoses and push-fit connections periodically for signs of wear or mineral build-up. The filter washers fitted to the hose connections should be checked and cleaned as part of any routine service. Where water hardness is a concern, descaling the hoses at regular intervals will help maintain flow performance.

Running the pump correctly:

The STN-2.0 B is activated by flow only - open the shower valve before expecting the pump to start. Never run the pump dry or against a closed valve for extended periods, as the built-in thermal protection is a safeguard rather than a substitute for correct operation. The pump is rated for continuous duty within its specified liquid temperature range of 5-60 °C.

We are pleased to offer FREE delivery on orders over €499.00 to anywhere in the Republic of Ireland and Northern Ireland, and our Click & Collect service is FREE on all orders.

All items are shipped from the Athlone Warehouse in Co. Westmeath, Ireland so no import duties apply to the island of Ireland.

Delivery Costs to Republic of Ireland are €6.99 for orders Under €499.00

Same Day Dispatch €9.99
Orders placed before 12pm are dispatched the same working day, helping your items reach you sooner. Excludes bulky items.

Large Bulky Items
Please be aware that large, bulky items (large appliances, white goods, etc.) have a delivery charge of €39.99 for bulky items or €59.99 for extra bulky items to ROI

- We are now delivering to Northern Ireland with all delivery costs equal to the Republic of Ireland.

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We now offer an exhange or refund on goods purchased online, and returned 14 days after purchase.

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