400L Unvented High Quality Stainless Steel Heat Pump Cylinder

The 400L Unvented Stainless Steel Heat Pump Cylinder is a premium hot water storage cylinder designed specifically for use with air source and ground source heat pumps. Manufactured from high-grade duplex stainless steel, it offers superior corrosion resistance, durability, and efficient heat transfer suitable for the lower temperature output of heat pump systems.

Key Features

• Capacity: 400 litres
• Material: High-quality duplex stainless steel ensuring excellent corrosion resistance and long service life
• Heat Exchanger: Large multi-pass corrugated stainless steel coil with a surface area of approximately 2.97 m² for rapid and efficient heat transfer at heat pump flow temperatures around 50–60°C
• Immersion Heater: 3 kW Incoloy immersion heater with thermostat pocket for emergency or backup heating, supporting legionella control
• Dimensions (HxD): Approximately 1613 mm height × 690 mm diameter
• Weight: Empty weight approx. 54.0 kg, full weight approx. 453.0 kg
• Insulation: Full 50 mm CFC & HCFC free polyurethane insulation to minimize heat loss
• Standing Heat Loss: Around 2.20 kWh per 24 hours
• ERP Band: C (energy efficiency rating)
• Warranty: 25 years cylinder warranty and 2 years on parts
• Additional Features: WRAS approved, includes 12 mm sensor probe pocket, compression fittings, expansion vessel, high limit stat, temperature & pressure relief valve, and 2 port motorized zone valve
• Design Benefits: Optimized coil design reduces pressure loss while maximizing heat exchange; insulation maintains cylinder temperature efficiently

Applications

• Ideal for residential and light commercial installations using air source or ground source heat pumps
• Designed to deliver mains pressure domestic hot water efficiently at lower heat pump temperatures
• Suitable for use where heat pumps may not regularly achieve high water temperatures, with backup heating for legionella risk management

Technical Specifications

This 400L stainless steel heat pump cylinder combines durable construction, energy-efficient insulation, and optimized coil design for excellent performance in modern heat pump domestic hot water systems. Its comprehensive standard components and long warranty provide peace of mind and ease of installation.

Please note: Delivery times may vary depending on location, with specific details outlined below.

Standard Delivery

UK Mainland 

• Delivery Time: 2–4 working days
• Free Delivery on all orders

Express Delivery

UK Mainland

• Delivery Time: 1–3 working days
• Delivery fee of £15

Channel Islands

• Postcodes Covered: GY*, IM*, JE* 
• Minimum Order: £50
• Delivery Fee: £70

Northern Ireland, Offshore Territories & Scottish Islands 

• Postcodes Covered: BT*, HS*, KW, ZE
• Minimum Order: £50
• Delivery Fee: £35

Same Day Delivery 

• Eligible Postcodes:
  E*, EC*, N*, NW*, SE*, SW*, W*, WC*, HA*, UB*, EN*, IG*, RM*, KT*, SM*, CR*, BR*, DA*, TW*
• Minimum Order: £50
• Same Day Delivery Fee: £60
• Special Requests or Locations:
  For areas outside these postcodes or urgent quotes, please email orders@qualityheating.co.uk and we’ll do our best to accommodate.

Collections

Want to collect your order instead?You’re welcome to do so — just email us at orders@qualityheating.co.uk or message us via WhatsApp with your preferred collection time, and we’ll confirm the details.

Collection address: 284 Water Rd, Unit 9, London, HA0 1HX