NRG Link

NRG Link – Dual‑Pressure Interlinking System

The NRG Link is a pre‑assembled, regulation‑compliant solution for safely connecting open‑vented solid fuel appliances to sealed heating systems.

It allows heat from a solid fuel stove or boiler to be shared with oil, gas, heat pump or solar systems without compromising safety, manufacturer requirements, or good installation practice. The unit is designed specifically to deal with the challenges of mixing open and sealed systems, which are often complex, time‑consuming and high‑risk when done using site‑assembled components.

What problem does NRG Link solve?

Solid fuel appliances are uncontrolled heat sources and must always be installed on a fully open, unobstructed gravity circuit with a heat leak, open expansion and cold feed. Sealed systems, on the other hand, rely on pumps, valves and pressurisation.

The NRG Link provides a safe and compliant interface between these fundamentally different systems. It allows the solid fuel appliance to operate independently and safely, while transferring usable heat into a sealed heating system when conditions are correct.

This removes the need for complex site‑built interlinking arrangements and avoids the common problems of:

• Restricted gravity circulation
• Incorrect valve placement
• Non‑compliant heat leak arrangements
• Overheating or system lock‑outs
• Excessive installation time and piping errors

How it works 

The NRG Link is installed in the primary gravity circuit of the solid fuel appliance.

• When the solid fuel appliance starts heating, the gravity circuit operates normally, supplying the heat leak.
• Once the return temperature reaches approximately 55 °C, the internal pipe thermostat activates the built‑in pumps.
• Heat is then transferred through the integral plate heat exchanger into the sealed system.
• If there is a power failure, the open gravity circuit continues to work safely, unaffected by pumps or valves.

Both systems remain hydraulically separate, while heat is transferred efficiently and automatically.

What’s included

The NRG Link is supplied as a complete, pre‑assembled unit, reducing site work and the risk of installation errors:

• Integrated plate heat exchanger
• Two high‑efficiency circulator pumps (primary and secondary)
• Factory‑set pipe thermostat (55 °C)
• Injector‑tee gravity boost arrangement
• Pre‑wired internal wiring centre
• Pre‑piped copper internals
• Air vent, non‑return valve and insulation
• Wall‑mounting bracket

Key benefits for installers

• Regulation‑compliant solution for open‑to‑sealed interlinking
• Reduced installation time and complexity
• Eliminates guesswork and piping errors
• Makes gravity heat leak circuits easier to design correctly
• Pre‑built and pre‑wired – no sourcing multiple components
• Allows solid fuel to work alongside oil, gas, heat pumps or solar
• Suitable for heating sealed domestic hot water via the secondary system

Typical applications

• Solid fuel stove combined with: 
  -Oil or gas boiler
  -Heat pump
  -Solar thermal system
• Upgrades where a solid fuel appliance is added to an existing sealed system
• Systems using NRG Zone manifolds or conventional zoning
• Installations where compliance, safety and reliability are critical

Technical overview

• Heat transfer capacity: 20 kW
• Max operating pressure (sealed side): 3 bar
• Factory‑set thermostat: 55 °C
• Power supply: 230 V AC
• Dimensions: 350 × 320 × 325 mm
• Fully insulated enclosure