Grant Expansion Vessel Mpss08 10Ltr Flat Grey Vortex Combi21

Vortex Combi 21 Pre Dec 2014

Grant Expansion Vessel – MPSS08

10 Litre Flat Grey Expansion Vessel for Grant Vortex Combi 21 Boilers

The Grant MPSS08 Expansion Vessel is a genuine 10-litre flat grey expansion vessel designed specifically for the Grant Vortex Combi 21 oil-fired boiler. This critical component manages pressure fluctuations within the sealed heating circuit, absorbing excess water volume when the system heats up—thereby protecting internal components from pressure-related damage.

Whether you're replacing a failed vessel or performing essential system maintenance, the MPSS08 ensures your boiler continues to operate safely, efficiently, and in full compliance with manufacturer standards.

 Key Features & Benefits

• Official Grant Part – MPSS08
  OEM expansion vessel made for direct fit into the Grant Vortex Combi 21 boiler.

• 10-Litre Capacity – Flat Design
  Compact flat-profile vessel fits neatly within the boiler casing or specified bracket position.

• Regulates Heating System Pressure
  Absorbs water expansion when heated to maintain safe operating pressure levels.

• Steel Body with Internal Diaphragm
  Separates air and water to maintain consistent pressure control and long-term reliability.

• Pre-Charged with Nitrogen
  Comes pre-set to standard pressure (typically ~1.0 bar) for fast and easy installation.

• Protects Boiler & Radiator System
  Reduces stress on pipework, pump, heat exchanger, and other components.

Compatible Grant Boiler Models

The MPSS08 Expansion Vessel is specifically suited to:

• Grant Vortex Combi 21kW (Internal model)

If you're unsure whether this expansion vessel fits your boiler, just send us your model or serial number—we'll confirm compatibility quickly.

When to Replace the Expansion Vessel

Replace your expansion vessel if:

• The system pressure frequently rises too high or trips the pressure relief valve

• You notice water leaking from the pressure relief pipe outside

• The vessel has no air charge left (you hear water sloshing or can't recharge it)

• You're conducting a major service, refurb, or system pressure fault diagnosis

A failed expansion vessel can cause erratic pressure, water discharge, and even boiler lockout—early replacement is key to avoiding bigger issues.

Technical Specifications

• Part Number: MPSS08

• Manufacturer: Grant UK

• Type: Flat expansion vessel

• System Type: Sealed central heating circuit

• Capacity: 10 litres

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