Grant Pressure Relief Valve Prv 3Bar Mpcbs50X Mpcbs123

V3 EXT COMBI was MPCBS50X 2.5bar

 Grant Pressure Relief Valve 3 Bar – MPCBS123X

Genuine 3-Bar Safety Valve for Grant Oil-Fired Combi and System Boilers

The Grant MPCBS123X Pressure Relief Valve (also referred to as PRV 3 Bar MPCBS50X) is a genuine Grant safety component designed to protect sealed central heating systems by releasing excess pressure. Suitable for a range of Grant Vortex and Euroflame boilers, this 3-bar valve acts as a crucial safety device that prevents potential damage to the heat exchanger, pipework, or expansion vessel during overpressure events.

Whether you're servicing a system or replacing a faulty valve that is leaking or constantly discharging, the MPCBS123X ensures your heating system stays protected, compliant, and reliable.

Key Features & Benefits

• Genuine Grant Part – MPCBS123X (Replaces MPCBS50X)
  Official manufacturer-approved pressure relief valve for use in compatible Grant oil boilers.

• Set to 3 Bar Pressure
  Automatically opens to release water when system pressure exceeds 3 bar—protecting critical components from failure.

• Pre-Calibrated for Safety & Reliability
  No on-site adjustment needed; fully factory-tested and certified for consistent operation.

• Robust Brass Construction
  Built to withstand prolonged use in high-pressure, high-temperature environments.

• Threaded for Easy Installation
  Direct replacement with standard compression or screw fitting—ideal for fast servicing.

• Essential Safety Feature
  Prevents boiler lockouts, pipe bursts, and expansion vessel overloads caused by overpressure.

 Compatible Grant Boiler Models

The MPCBS123X PRV is suitable for use with various Grant oil-fired boiler models, including:

• Grant Vortex Combi 21 / 26 / 36 kW

• Grant Vortex System and Utility Boilers (selected models)

• Grant Euroflame models using a 3-bar PRV

Not sure if this valve fits your boiler? Contact us with your serial number or part reference—we’ll help you find the correct match.

When to Replace the Pressure Relief Valve

Replace the PRV if:

• The valve is leaking or dripping continuously, even when system pressure is normal

• It fails to open during pressure spikes, causing boiler lockouts

• The valve has visible signs of corrosion or limescale build-up

• You’re conducting a system pressure fault diagnosis or replacing the expansion vessel

A malfunctioning PRV puts your entire heating system at risk—replacing it early avoids unnecessary damage and costly repairs.

Technical Specifications

• Part Number: MPCBS123X (supersedes MPCBS50X)

• Manufacturer: Grant UK

• Type: Pressure relief valve for sealed heating systems

• Material: Solid brass with pre-set internal spring

• Pressure Setting: 3.0 bar

• Connection Type: Threaded (check manual for fitting details)

• Application: Combi, system, and sealed heating boilers

• Operation: Automatic release at overpressure with spring-loaded valve closure