NRG Awareness V9.4 Link Dual Pressure Interlinking System Installation Guide

V9.4 Link Dual Pressure Interlinking System

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Specifications

• Electric supply: 200 – 240 V (AC) ; 50 – 60 Hz
• Circulators Power consumption: (2 No.) 4 – 42 W
• Pipe Thermostat Temperature Range: Max Ambient temperature
• Plate Exchanger Heat Capacity: 20 kW

Product Usage Instructions

1. Introduction & General Information

This product is the NRG Link Dual-Pressure Interlinking System
designed for interconnecting sealed to open (Solid Fuel) heating
systems. It includes various components such as Plate Heat
Exchanger, Non Return Valve, Circulator Pumps, Wiring Centre, Pipe
Thermostat, Plumbing Connections, and more.

2. Installation Guidelines

Install the NRG Link system in compliance with all relevant
appliance manufacturers’ instructions and codes of practice. Ensure
a suitably competent person carries out the installation. Make sure
the boilers used are CE approved and properly commissioned to
maintain warranties.

3. Precautions

Wait for the appliance to cool down before any maintenance work.
Be cautious of high voltage components to avoid electrocution
hazards. Prevent freezing by taking appropriate measures during low
temperatures.

4. Preliminary System Checks

Prior to installation, conduct thorough system checks to ensure
all components are in working condition and compatible with the NRG
Link system.

5. NRG Link General Information

Familiarize yourself with the operating modes and installation
guidelines provided in the manual to optimize the performance of
the NRG Link system.

FAQ

1. Is professional installation required for the NRG Link

system?

Yes, it is recommended to have a suitably competent person
install the NRG Link system in compliance with all relevant
regulations and guidelines.

2. Can any type of boiler be used with the NRG Link

system?

No, ensure that the boilers used are CE approved and follow
proper commissioning procedures to avoid invalidating
warranties.

“`

NRG Awareness
© Copyright 2018 Sea Box Energy

INSTALLATION AND TRAINING MANUAL
NRG Link Dual-Pressure Interlinking System for interconnecting sealed to
open (Solid Fuel) heating systems
Including: Plate Heat Exchanger, Non Return Valve Pre-assembled Copper Tubing, Air Vent,
1 1/4″ Internal Primaries, Primary Side Injector, 2x Lowara 25-6 130 Ecocirc Circulator Pumps, Pre-wired Wiring Centre / Terminals, Pipe Thermostat, 1″ Plumbing Connections, Insulated Cover & Mounting Bracket.

CONTENTS

Technical Data & Safety Guidelines 2

1.0 Introduction & General Information 3

1.1 Introduction

3

1.2 Important

3

1.3 Installation Guidelines

3

2.0 The Solid Fuel Appliance

3

2.1 Secondary (Interlinked) Appliance 3

3.0 Precautions with Solid Fuel

3

4.0 Preliminary System Checks

3

5.0 NRG Link General Information

4

5.1 NRG Link Operating Modes

4

5.2 NRG Link Installation Guidelines 4

6.0 The Solid Fuel Appliance

5

7.0 Gravity Circuit

5

7.1 Guideline on the Gravity Circuit 6

8.0 The Use of Mechanical Valves

6

9.0 Cold Feed & Expansion Tank / Cistern 6

10.0 Electric Wiring Information

7

11.0 Internal Pipe Thermostat

7

12.0 Dual Boiler Call Strategy

7

13.0 Precautions and Questions & Answers 8

Example Pipework & Wiring Diagrams 9

NRG Link – Basic System Principles 14

Design Assistance Sketch Pad

16

1

CAUTION! YOUR SAFETY IS INVOLVED. FAILURE TO FOLLOW THESE INSTRUCTIONS MAY RESULT IN INJURY.
LEAVE THIS MANUAL AS A REFERENCE GUIDE FOR THE USER

WARNING Risk of damage to or malfunction of the appliance. Pay special attention to the warnings concerning danger to people.
DANGER OF BURNS Wait for the appliance to cool down before working on the parts exposed to heat.
DANGER – HIGH VOLTAGE Live components – electrocution hazard.
DANGER OF FREEZING Possible danger due to the formation of ice due to low temperatures.
IMPORTANT INFORMATION Information to read with particular care as it is useful for correct system operation.
GENERIC PROHIBITION It is forbidden to do/use the things indicated alongside the symbol.
Technical data
Electric supply: 200 – 240 V (AC) ; 50 – 60 Hz

Circulators Power consumption:

(2 No.) 4 – 42 W

Pipe Thermostat Temperature Range Max Ambient temperature Switch Rate Switch Type Switch Differential Switch Configuration
Factory Setting (on primary return position)

30 – 90°C 45°C
6(2.5) A SPDT (Type 1B)
6-10°C 1 – 3 Make on temperature rise 1 – 2 Break on Temperature rise
55°C

Plate Exchanger

Heat Capacity (based on water temperatures and flow rates as outlined below 20 kW

Circuit

Primary

Secondary

Primary circuit fluid

Water

Water

Fluid flow rate

1.75 m³/h

1.75 m³/h

Fluid speed

0.2182 m/s

0.2177 m/s

Inlet temperature

75°C

56°C

Outlet temperature

65°C

66°C

Pressure drop

0.696 mH20

0.710 mH20

Partial exchange coefficient

21137

20229

2

1.0 Introduction and General Information Fig 1

1.3 Installation Guidelines This manual gives supplementary guidance for safe and effective interlinking. It is to be applied in conjunction with the open and sealed-system boiler installation instructions.

The interconnection between a sealed and an open vented systems must be installed by a suitably competent person in compliance with all relevant appliance manufacturers’ directions, codes of practice, trade regulations and by-laws.

It is the responsibility of the installer to ensure that the boiler(s) used are CE approved and are properly commissioned. Failure to do so may invalidate the boiler(s) and NRG-Link’s guarantees.

2.0 The Solid Fuel Appliance This can be a stove/room heater approved to EN13240, with a maximum boiler to water output of 20 kW burning either biomass or mineral fuel.

2.1 Secondary (Interlinked) Appliance

We would like to thank you for purchasing the NRG link unit. This manual contains technical and installation guidelines to assist with the correct installation of the system.
1.1 Introduction
Experience with conventional methods has shown that improperly installed solid fuel interlinked systems are troublesome, difficult to control, most often very inefficient and potentially dangerous.
The NRG Link is a plumbing and wiring interface method used to interconnect the primary open vented part of a wet’ Solid Fuel Appliance installation to any other wet sealed or open vented system that uses an alternative fuel such as Oil, Gas, Heat Pump or Solar heating for common heat distribution in a reliable, simple and cost-effective way using standard well established principles with a safe and compact design. 1.2 Important All uncontrolled solid fuel systems must be open vented and include an open gravity-fed orprimary’ heat leak circuit.

The secondary heating appliance in the interlinked system could be a conventional or condensing oil or gas-fired boiler, a cooker, solar heating or a heat pump. In all instances, it is essential to ensure that the selected secondary appliance can handle or adapt to the additional heat input from the uncontrolled solid fuel source.
3.0 Precautions With Solid Fuel System
This NRG Link has been designed to work in normal circumstances at a temperature lower than the boiling point of water at atmospheric pressure. Care should be taken to reduce the risk of the solid fuel appliance boiling. The maximum
recommended design temperature is 75°C
4.0 Preliminary System Checks
Before installing the NRG Link, the sealed system must be cleaned and flushed to eliminate residual thread-cutting swarf, solder and any solvents, using suitable off-the-shelf non-acid and nonalkaline products that do not damage the metal or fibrous parts. To protect the system from corrosion, sludge and scale, use inhibitors heating circuits. Use these products in strict compliance with the manufacturers’ instructions.

3

NRG Link Data
325 90
Vent
A

320 R2 F2

A

B

Port Connections F1 1″ Female Iron – Flow from Solid Fuel R1 1″ Female Iron – Return to Solid Fuel F2 1″ Female Iron – Flow to Heat Leak R2 1″ Female Iron – Return from Heat Leak F3 1″ Male Iron – Flow to Sealed System R3 1″ Female Iron – Return from Sealed System

Fig 2

Vent

350 B

Mounting Bracket

F3

R3 82

Left

60

160

60

R1 F1 90
75 40 70 85 50

F3 Right
90
325

Dimensions: 350mm(H) x 320mm(W) x 325mm(D) 5.1 NRG Link Operation Modes

Weight: 8 kg Max Operating Temperature: 110°C Max Pressure: 3 Bar Heat Transfer Capacity: 20 kW
5.0 NRG Link General Information

The unit operates under 2 different conditions; Gravity Circulation and Pumped Circulation:
On initial solid fuel heat-up, the gravity circuit supplies the heat leak and circulates through the NRG Links primary-side pipework until the return pipe reaches the pipe thermostat’s set point (min 55°C) to operate the pumps.

The NRG Link can automatically manage the exchange of heat from the open system to the sealed system when the internal pipe thermostat switches contacts and activates the built-in pumps. The heat from the solid fuel circuit is then transferred to the sealed system by the unit’s plate exchanger.
The unit is also designed to facilitate an unobstructed (1″ minimum) open vented gravity circuit from a solid fuel appliance to an appropriate heat leak medium such as a DHW cylinder, a heat leak radiator circuit or a combination of both.

When this happens the primary (right hand) pump draws the primary hot water through the plate heat exchanger and then injects it back into the primary return having exchanged the heat to the secondary side. This also boosts the circulation in the gravity circuit. At the same time, the secondary (left hand) pump circulates a counterflow through the plate heat exchanger, collecting the heat from the primary side for delivery to the sealed heating system.
5.2 NRG Link Installation Guidelines

The NRG Link principle is based on a wellestablished ‘ Injector Tee ‘ method that has proven to be reliable, simple, cost-effective and safe.

The NRG Link must be a part of the gravity circuit and positioned to allow the flow from the solid fuel appliance to rise upwards through the flow pipe F1-F2 and return in the adjacent pipe R2-R1.
4

For the NRG Link to operate safely and

The velocity of a gravity circuit depends primarily

correctly the exchanged heat must have an on the up-feed height from the appliance to the

open path to the sealed (secondary) systems heat top of the circuit (excluding the vent/expansion

emitters at all times. The heat emitters on the

height), the diameter of the pipe (minimum 28mm

secondary system should have sufficient capacity / 1″), the condition and smoothness of the internal

to handle the solid fuel appliance heat output at pipe walls, the slope of the pipe, and the

full load.

temperature differential (Delta T) across the

Note: The return pipe from the sealed system

circuit taking the heat leak into account.

must include a 28 mm (1″) 80 to 100 micron

Every opportunity should be taken to maximise

strainer to prevent any debris entering and

the upward angle of the primary circuit pipework

obstructing the NRG Link plate heat exchanger. from the solid fuel appliance and most particularly

6.0 The Solid Fuel Appliance

when the flow pipe exits the boiler. Here a minimum incline of 20 degrees would be most

Continuous combustion type solid fuel appliances advantageous. The minimal slope rising to the

require that the heat energy is safely transferred away from the heat source until the fuel source is

vent/expansion connection point is 1 degree at each section of the primary circuit. This equates to

exhausted. Experience with conventional methods about 20 mm/m or just over 1/4″ / ft.

has shown that improperly installed solid fuel

A maximized vertical length of the flow pipe from

interlinked systems are troublesome, difficult to the solid fuel appliance to the heat leak will

control, most often very inefficient and potentially positively affect the amount of “thermal lift” and

dangerous.

result in stronger water flow in the gravity circuit.

It is essential to comply with manufacturer’s instructions especially with regard to the flow and return piping connections where there are optional ports available on the boiler.

The length of the initial horizontal pipe-run is a critical factor in how well the solid fuel gravity circuit will operate as too long will delay the initial circulation and restrict the flow.

Some appliances require that both connections are on the same side and others require diagonally

Therefore, the ideal position for heat leak cylinders/radiators is directly above the solid fuel

opposite connection points. Failure to comply with the particular manufacturer’s instructions could

boiler and the heat leak should connect as close as possible to the solid fuel appliance.

render the appliance unsafe as well as reduce its efficiency.

Due to heat losses through the pipe, a three-story building is the practical limit for

The final piping configuration must not inhibit the safe or proper use of any one appliance e.g. by restricting the appliance heat output when it is operating.

a gravity hot water circuit. Above this, the pipe losses can restrict or even disrupt the gravity circulation. This could lead to the water close to the solid fuel appliance overheating and potentially boiling.

7.0 Gravity Circuit

It is vital that any heat leak radiator or DHW heat

When the solid fuel appliance is heating the hot leak circuit is sized to dissipate the ‘turndown’

water in the primary flow pipe expands. This

output according to the stove manufacturer’s

makes its density lower (lighter) and causes it to guidelines. That is where the solid fuel appliance

rise. As the hot water rises it will eventually meet has an automatic turndown air damper-

the heat leak or NRG Link. When heat is removed mechanism or an automatic facility to control or

by the heat leak or heat transferred to the sealed maintain combustion when the appliance has

system by NRG Link’s heat exchanger, the water reached its maximum safe operating water

will cool, increase in density and fall downwards temperature output and the mechanism delivers a

through the return pipe to be reheated in the solid lower supply of air to the combustion chamber to

fuel appliance. The combination of the hot water maintain minimal heat delivery. Generally, the

rising and the cooler water falling creates a

gravity circulation.

5

turndown output of a solid fuel appliance is at least 15% of the stove’s output to water.

vicinity and be in accordance with guidelines and regulations.

The overall system plan should utilise as much useful heat from the ‘ heat leak’ emission as possible rather than dissipating that heat to an unused location where it is of no advantage.

As an insulated DHW cylinder is no

longer accepted as a reliable heat leak,

it may be necessary to include additional heat

leak radiator(s) in a primary heat leak circuit.

The gravity circuit must be open vented and unobstructed by any pumps, non- return valves, motorised or mechanical valves or any other restriction. This primary circuit must also include an open cold feed and a heat leak facility. It must be designed to operate by gravity circulation alone, independent of an electric power supply. The circuit should rise continuously to a Vent /Expansion tee at a high point. It must also pass through the NRG Link and include a Heat Leak in its route. When the water is cooled by the heat exchange it should fall back to the appliance through the Primary return which again should be designed to allow air to rise to the open vent.

7.1 Guidelines on the Gravity Circuit

Only metallic pipe should be used on primary circuits.

Manual or automatic air vents must not

be used on primary circuits as the

system could become extremely dangerous if

any of its mechanical parts fail and trap air,

preventing the gravity circulation.

The total gravity circuit length should be less than 25 M in total including both the Flow & Return pipe.

The number of sharp pipe elbows/bends on the primary circuit should be minimised. Preferably use manual pipe bends formed by a bending spring or pipe bender rather than sharp fittings.

The installer must ensure that there is a

properly sized safety valve fitted directly

on each appliance or on its flow pipe in direct

unobstructed contact with the appliance’s

water contents. The valve outlet must

terminate safely at a low level. The pressure

relief device must be capable of expelling any

excess system pressure. The valve outlet must

not be a source of danger to anyone in the

Pressurised DHW cylinders cannot be used as heat leaks. They can, however, be heated from the solid fuel appliance through the secondary side of the NRG Link (see figure 8).
8.0 The use of Mechanical Valves
Non-Return Valves (NRVs) and motorised valves (MVs) are safe to use as inter- linking distribution control methods on the secondary pipework as detailed in the schematics included further on.
Thermostatic radiator valves must never be used on primary heat leak radiators or on any radiators that would be allocated the function of dissipating heat from the solid fuel appliance.
Motorised valves used on the secondary side heat dissipation circuits must be the ‘ Normally Open’ (Power Close) type. This will ensure that any potentially defective valve will not form a blockage to the circulating heated volume from the solid fuel system that could lead to a dangerous system.
Fig 6 shows an example method of bypassing secondary system motorised valves where the NRG Link’s output is piped to inlet points on the heating circuits, beyond the control valves, to access radiator circuits for the necessary heat dissipation function.
Fig 1
Minimum 450 mm Above Water Level
Expansion Pipe

6

9.0 Cold Feed & Expansion Tank / Cistern
A feed and expansion (F&E) cistern/tank fabricated of galvanised or stainless steel must be used on all solid fuel open-vented central-heating systems. The purpose of the F&E tank is to ensure that an open vented circuit never becomes pressurised as well as provide a receptacle for any heated/expanded volume that returns to the system when the expanded volume cools. If the F&E tank is undersized, it will overflow when the system is heated and refill on cooling with fresh oxygenated water. This will result in increased system corrosion and other associated problems.
The F&E tank should be sized and located in accordance with all regulations and manufacturer’s guidelines.

The cold feed and expansion vent pipework must be entirely metallic.
The connection for the cold feed must be taken from the side of the cistern and never from the bottom to prevent debris that might have accumulated in the cistern from being drawn down into the system.
The ball float and valve should be metallic.
10.0 Risk of electric shock.
The internal wiring centre is live when installed. Isolate the electric supply before carrying out any work. Failure to follow these instructions may result in personal injury or damage to property.
11.0 Internal Pipe Thermostat

The following points are critical to ensure proper installation of the F&E tank (see figure 3 for reference):

The internal pipe thermostat in the NRG Link is mounted on the gravity circuit return pipe and it is set at 55°C.

The F&E tank should be sized and set up to accommodate (without overflowing) at least 4% expansion of the total system contents, i.e. boiler(s), pipework, radiators and cylinder coil or thermal store etc.
The F&E cistern and the system expansion vent pipe above the cistern must be located at the highest practicable point in the system
The overflow pipe must be at least 22 mm diameter and capable of handling boiling water.
When the heating system is up to operating temperature, there must be at least 25 mm air gap between the surface of the expanded water and the invert level of the overflow pipe.
The expansion vent pipe should have a minimum diameter of 22 mm and a gooseneck bend that terminate above F&E tank. In the event of the system water becoming overheated the expansion vent pipe will allow the water to discharge into the F&E tank, preventing dangerous pressure buildup.
Shut-off valves or any other mechanical item that might interfere with or obstruct the flow must never be installed on the expansion vent pipe or the cold feed.

In some instances, where for example the NRG Link is located close to or above a DHW cylinder it will be necessary to ensure that the thermostat is not switched ‘on’ unnecessarily by heat drifting from the stored hot water. In that case, the thermostat must be moved to a lower position on the return, closer to the solid fuel stove.
To ensure continued safe operation it is imperative that the pipe thermostat is securely fastened to the primary circuit pipework and that its calibration be checked periodically by confirming that the stat contacts switch properly when the set-point is reached.
12.0 Dual Boiler Call Strategy
If the solid fuel boiler is not capable of heating the entire system then it would make sense to allow the secondary boiler to continue working but it is important to consider the effect of the hightemperature solid fuel boiler’s output on the efficiency of the secondary boiler.
With many system configurations, it is possible to use both appliances at the same time. This is particularly the case with most oil boilers or stoves. Certain gas boilers or heat pumps may detect the increase in their return water temperature from the incoming solid fuel source

7

and may wrongly identify it as an internal fault and go to a ‘lockout’ state.
If that is the case, a ‘switch-live’ from the NRG Link’s pipe thermostat can be used to output an additional live switch input to a relay that will switch the second boiler ‘off’ when the solid fuel boiler is working. However, if both boilers can work in tandem then the second boiler can provide any additional heat required when the solid fuel appliance is in operation.
The NRG Zone Manifold from NRG Awareness is particularly suited for allowing two different temperature boilers to work together.
13.0 Precautions to Pipe Freezing
There are two distinct dangers to system water freezing in pipes during colder conditions. One is where any water trapped between two freezing/ expanding ice blockages can become pressurised enough to burst the pipe wall. This may lead to potential water damage to the property. The second issue is where an ice blockage will seal the water contents within the system which can then have catastrophic results if it is subsequently heated to a degree where the total system is over pressurised. This is why a properly fitted safety valve located on the flow pipe in proximity to the solid fuel appliance is a critical component.
Therefore, all vulnerable pipework should be sufficiently protected and insulated, especially in unheated areas like the attic.
14.0 Questions & Answers
How safe are solid fuel systems?
Solid fuel systems are probably the safest of all systems if they are installed correctly and follow the basic guidelines set out in this manual but rule number one is that the system must not rely on mechanical devices to maintain their safety. There are more safety features to a good solid fuel system than most other systems. For example, it has a perfect open path to an open expansion tank.

What are the most critical issues when designing solid fuel systems?
1. There must be absolutely no mechanical device(s) in the primary water flow circuit.
2. The expansion and cold feed must not have valves or other obstructions.
3. The Cold Feed must have a direct path to the solid fuel stove at all times and must not pass through plate exchangers, cylinder coils, radiators or other similar equipment to reach the overheating appliance.
4. The appliance’s heat output must not be larger than the heat load of the system it supplies.
5. The Heat Leak on the primary circuit must be able to distribute the heat output from a fully loaded appliance when the air dampers are closed.
Can Solid Fuel Systems be used efficiently with low-temperature systems like heat pumps or under-floor heating systems?
Absolutely yes if the correct design criteria are applied. If you are designing a system NRG Awareness offers technical support by phone or email to assist. We can also provide system schematic diagrams for both the plumbing and wiring work. NRG Awareness can also provide ancillary control equipment; panels etc. to help deal with any unusual queries or control issues.
How cost effective is the NRG Link?
We find that installers do not take the true cost of installing dual heating systems into account. Often we find that too much time is wasted trying to figure out how exactly to put the system together, sourcing the parts, & taking the wiring costs and actual installation time into account. If the costs are properly compared then NRG Link is the best choice by far. It is the only procurable system available that complies with all manufacturer’s guideline and regulations.
Technical Support NRG Link Technical support is available at: www.nrgawareness.com – www.nrgzone.ie
8

NRG Link Basic Principle – Including Secondary Heat Distribution to an NRG Zone 5 Manifold. Fig 4

NRG Zone

NRG Link

Expansion / Vent Pipe

Expansion Tank

Auto Air Vent

Circulation Pump A

Circulation Pump B

Heat Leak Cylinder/ Radiators

Primary Gravity Circuit
Safety Valve

Zone A

Zone B

Zone C

Plate Heat Exchanger

Injector Tee

Cold Feed

Solid Fuel Stove

NOTE; In this instance the return to the heat pump buffer should be connected to the lower side connection on the NRGZone.
This will collect the coolest returning water from the zones and increase the efficiency of the heat pump.
It will also permit the solid fuel appliance and the heat pump to operate together under controlled conditions.
The return to the solid fuel stove should be connected to the middle side connection on the NRGZone.
This will collect any hotter bypassing water in the NRGZone and increase the performance of the stove by maintaining a return temperature above 55 C when controlled by the built-in pipe thermostat in the NRG Link.
It will also permit the solid fuel appliance and the heat pump to operate together under controlled conditions.
The by pass vent shown on the solid fuel Primary circuit allows air at a high level in the return pipe to escape upwards to the Primary Flow where it is released through the open vent
Underfloor heating Manifold 2

NRGZone 4 NRGZone 4
DHW

EXAMPLE SINGLE STORY INTERLINK HEAT PUMP & SOLID FUEL STOVE

Vent/Expansion Tank & Cold Feed

Minimum 400mm

Fig 17

3/4″
Primary Flow piped directly above the primary Return to allow air from the return pipe to vent through the bypass

Fall

By Pass

1″

Vent

1/2″ High Point

Fig 5

Heat Leak Radiator at High Level in wardrobe or dressing room
Aluminium Section Radiator – 1″ Connections
1″

1″

Heat-Lock

Loop

Attic Floor

1″
Sealed System AAV AAV

Diverter Safety

Valve

Valve

NRV

NRGZone 4

Buffer Vessel

Open System
System Fill Point

Strainer

Pressure Vessel

Underfloor heating Manifold 1

Heat Pump

1″

1″

Solid Fuel Stove

Safety Valve

Ground Floor

Figure 5 shows how an `Up&Over’ gravity heat leak system could be designed. The heat leak radiator is used to dissipate excess heat when there is a power shortage. The layout also show how to pipe a system with a sealed system heat

pump that require a buffer tank and an open

solid fuel system. In this instance a DHW zone

and 2 separate Under-floor heating zones can

utilise the heat from heat pump and solid fuel

system simultaneously.

9

NRG Link interconnection of Solid Fuel appliances with Heat Leak.

In the examples below the NRG Link system is sited above the solid fuel appliance and the unit’s integral primary pipework facilitates a gravity fed circuit to heat leak circuits above the units mounting location.

Fig 6 shows a solid fuel stove with a primary heat leak circuit to a conventional open vented DHW dual coil cylinder with 1″ open gravity circuit from the stove to the cylinder.

DHW DHW Zone

Fig 6
If the DHW cylinder is insulated a heat leak radiator must be added to the gravity circuit

The secondary sealed system is

Sealed System

interlinked on the system side

of an `S’ Plan motorised zone

valve control configuration with non return valves (NRV’s)

Boiler

Motorised Valve

preventing any back-feeding

between the systems and

Pressure Vessel

Auto Bypass Safety Valve Valve

zones

CH Zone 2

HeLaot-oLpock

Motorised Valve

NRV

Motorised Valve
CH Zone 1

NRV

Strainer

System
Cooker

Fig 7 shows an open vented solid fuel stove with a heat leak to a conventional open vented DHW dual coil cylinder.
The secondary sealed system uses an NRG Zone 4 manifold creating a radiator, under floor heating and a DHW circuit.

See Wiring Example Diagram (Fig 13)

Sealed System

If the DHW cylinder is insulated a heat leak radiator must be added to the gravity circuit
Heating Zone 2

AAV DHW

Fig 7
Open Vented System

In this instance the manifold allows the coldest zone return water to return to the condensing boiler while the stove maintains a 55°C return temperature.
Fig 8 shows an interconnection between an open vented solid fuel stove with a heat leak radiator – towel rail circuit and a closed system combi-boiler.
The two appliances are isolated from each other by non return valves on the interlinking pipework.
In each of the three examples above the heat leak circuit receives heated water from the solid fuel appliance before the NRG Link stat allows the heat to be transferred to the sealed system.

Oil Boiler

AAV
NRGZone 4
Underfloor Heating Manifold

Strainer

Solid Fuel Stove

Sealed System

Example Heat Leak Radiator

Example Heat leak Towel Rail

Fig 8
Open Vented System

Heating Circuit

Combi Boiler
Hot Cold
CWS

NRV

Solid Fuel Stove
10

NRG Link interconnection of Solid Fuel appliances with Heat Leak located below the NRG Link system. In the examples below the NRG Link system is sited above the solid fuel appliance and the unit’s integral primary pipework facilitates a gravity fed circuit to a heat leak circuit below the units mounting location.

Fig 9 shows a solid fuel stove with a 1″ open gravity circuit from the stove to the heat leak.

Sealed System

In this instance the NRG Link can

Radiator Circuit

exchange heat from the solid Strainer
fuel stove to the sealed heating

system before it reaches the

heat leak circuit.

Gas

Boiler

The sealed system comprises a

Pressurised DHW
P&T Valve

gas combi-boiler which is isolated from the solid fuel heat input by Non Return Valves (NRVs) .
The main benefit of this method

Temperature Mixing Valve

M

H

Hot

C

Cold

Cold Feed

P

Pressurisation Pump

NRV

AAV

NRV

AAV NRV
NRGZone 5

Underfloor Heating Manifold

is that the heat leak circuit only

receives residual heat from the

gravity circuit and the sealed

system can gain the bulk of the

heat generated by the solid fuel

appliance.

Fig 9
Open System
Example Heat leak Towel Rail
Example Heat Leak Radiator
Solid Fuel Stove

Fig 10 shows an interconnection between an open vented solid fuel stove with a heat leak radiator circuit and a closed system Heat Pump.
The NRG Link, controlled by it’s pipe stat is used to prioritise the the solid fuel system heat to the sealed system.

Sealed System

Radiator Circuit

AAV NRV

NRGZone
5

Strainer
Example Heat Leak Radiator

The interlink is completed using an NRG Zone 5 manifold allowing the heat pump to have primary access to the coldest zone return water to increase it’s efficiency and to work in tandem with the stove.

NRV Heat Pump

Pressurised DHW System

Optional

Hot

Heat Pump

Buffer

Cold

Radiator Circuit PresPsuumripsation

NRV

Solid Fuel Stove

The pressurised DHW system has indirect controllable access to the heat from the solid fuel appliance which complies with all regulations and good work practice

See Example Wiring Diagram (Fig 16)

Fig 10
Open System
11

NRG Link Pipe Thermostat

Fig 11
NRG Link Internal Wiring

(55°C)

P1 Primary

E

Pump

E

P2

Secondary Pump

E

E
Basic Wiring

L N E SL

Secondary System Switch

3 amp

E N

Power Supply

L

Fig 13

NRG Link Example Wiring for Fig 4

Pipe Thermostat

(55°C)

P1

Primary

E

Pump

C NC

E

Relay

P2

Secondary Pump

NO

E E

LN

L N E SL

Secondary Boiler OFF

NRG Link Boiler External Controls

Fig 12

Pipe

Stat

Boiler Wiring Centre

(55°C) P1
E

12 LNE

E

E

P2

E
C NC
E

L N E SL

Relay NO
Secondary L N System Switch

Power Supply

E

E

N

Fused Double 3 amp

L

Pole Isolator
Example Boiler-Override Wiring

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16

3N
amp
E
LEN
Power
N N

12 Volt Free Boiler
LEN

L SL
EN Room Stat 1

L SL
EN Room Stat 2

CEL NO N

CEL NO N

CH MV 1 CH MV 2

SL L EN DHW
Stat
CEL NO N
HW MV

Power Supply
E N
L

N

N

1 23

N

N

E L CH CH HW
N

N
Example motorized valve system with Boiler-Override Wiring

NRG Link Internal wiring has pre-wired connections to the internal primary and secondary pumps through the pipe thermostat as shown in Fig 11. The switch live to the pumps can also be used to trigger a control relay (Not supplied) for auxiliary functions, for example as shown in Fig 12 above where a relay breaks the external control link to de-energise the secondary boiler when the NRG Link Stat detects that the solid fuel appliance has reached its heat delivery set-point.

Fig 13 shows NRG Link with a 3 Motorised Valve (S’ Plan) with a common power supply. If required, an additional relay may be used to break theS Plan’ volt free boiler control Link at terminals 7 (C) & 5 (NC) on the controls terminal strip when the relay coil is energised by the NRG Link. By this means the secondary boiler can be switched off when the solid fuel (Biomass) boiler has achieved its set-point on the NRG Link internal thermostat.

12

Example NRG Link Wiring with an NRG Lex System Controls Module (SMC) NRG Lex is a pre-configured electronic wiring center with 4 fused (independent 1 A ) zones, each of which will call the boiler(s) when any of the 4 zones call. The unit also includes 4 isolated inputs to separate auxiliary relay that may be used to carry out additional system controls tasks such as adding extra boilers or control functions when certain wiring control conditions are met. It also has a 6.3 A mains fuse, two 3 A boiler fuses, a 3 A general clock fuse and a Frost/Auxiliary fuse to supply power for any optional ancillary use.
The diagrams that follow show how the NRG Lex SCM may be used to configure interconnected linkups using NRG Link with pumped based systems where selected auxiliary functions can isolate a second boiler and/or override particular zone controls to dissipate heat from the solid fuel stove when its pipe stat calls. The various diagrams show different zone control types but they are not exclusive to any one interlinking method. The alternative zone controls are interchangeable in the other diagrams as required.
NRG Lex SCM

Figure 14 shows an NRG Lex SCM with a four-zone heating system using a switch live boiler interlinked with a solid fuel appliance using NRG Link. In this configuration, the NRG Link’s output will operate its own pumps as well as the NRG Lex’s auxiliary

Fig 14
relay to turn the boiler off by switching the auxiliary relay contacts which will also bypass Zone D’s controls to run the zone’s pump to dissipate the heat when the solid fuel appliance return temperature is above 55°C.

NRG Lex SCM

Example wiring Fig 4
Figure 15 shows an NRG Lex with an example three zone wireless heating system, switch live boiler and a solid fuel appliance using NRG Link. This example allows the boiler to continue firing when the NRG Lex solid fuel stat is above 55°C. This will also cause the double pole auxiliary relay to override the controls in Zone B & C to energise both zone pumps and dissipate the heat from the solid fuel appliance.

Fig 15
It is also important to note that when the solid fuel appliance has caused the auxiliary relay to switch that the power supply for zone pumps B & C will change to the auxiliary power supply at terminals 27 & 28 with power isolation provided by the relay.
This method is only applicable when the system can handle the different temperature outputs from the two boiler appliances.
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NRG Lex SCM

Example wiring for Fig 10
Fig 16 shows an example of a wiring layout to control a solid fuel appliance with a heat pump. The heat pump is called `On’ by the zone controls but also will be switched off if the pipe stat on the heat pump return detects overtemperature. In standard mode the zone pumps

Fig 16
are powered by the zone controls (from A4, B4, C4 or D4) but in this instance the auxiliary relay is also used to override the controls of zone B & C where the auxiliary power supply from 27 and 28 are used to run the 2 zone pumps through the switched relay connections 17 & 18.

If the DHW cylinder is insulated a heat leak radiator must be added to the gravity circuit

Unobstructed Gravity Circuit

Gravity Circuit

Open Vent/ Expansion

Open Cold Feed

Expansion Tank

NRG Link Pipe Thermostat
(55°C) P1
P2

Primary Pump
Secondary Pump

C NC
Relay NO LN

L N E SL

Secondary Boiler OFF

Power Supply
N L

AAV

DHW

Zone 1

Strainer

Safety Valve

Solid Fuel Stove

Pressure Vessel
AAV

Safety Valve

Boiler

Motorised Valve
AAV

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16

3N
amp
E
LEN Power
N N N N N N N

12 Volt Free Boiler
LEN

L SL
EN Room Stat 1

L SL
EN Room Stat 2

CEL NO N

CEL NO N

CH MV 1 CH MV 2

SL L EN DHW
Stat
CEL NO N
HW MV

1 23 N E L CH CH HW

Zone 3

Fig 17
Zone 2

Example – 3 zone Wiring S’ Plan used to control and interlink with a boiler and a solid fuel stove . This variation of anS’ Plan motorised valve wiring diagram will prevent the Oil Boiler firing and allow the 2 zones (2 & 3) to receive heat output from the NRG Link when it’s internal pipe thermostat stat calls. The secondary output from the NRG Link is connected on the system side of, or beyond the motorised valves, therefore it will not be necessary to open any of those valves to allow the heat from the solid fuel to be dispersed to the zones.
14

In this instance the return to the heat pump buffer should be connected to the lower side connection on the NRGZone.
This will collect the coolest returning water from the zones and increase the efficiency of the heat pump.
It will also permit the solid fuel appliance and the heat pump to operate together under controlled conditions

AAV
NRGZone 4

In this instance the return to the solid fuel stove should be connected to the middle side connection on the NRGZone.
This will collect any hotter bypassing water in the NRGZone and increase the performance of the stove by maintaining a return temperature above 55 C when controlled by the built-in pipe thermostat in the NRG Link.
It will also permit the solid fuel appliance and the heat pump to operate together under controlled conditions.

Vent/Expansion Tank & Cold Feed

Minimum 400mm

Fig 18

Attic

DHW

1″

AAV 1″

Heat-Lock Loop

Radiator Heating Manifold 2

Heat Pump

First Floor

Buffer Vessel

Safety Valve NRV

AAV

NRGZone 4

Strainer

Pressure Vessel

If the DHW cylinder is insulated a heat leak radiator must be added to the gravity circuit
Underfloor heating Manifold 1

1″

1″

Solid Fuel Stove
Safety Valve

Ground Floor
Example – 3 zone NRG Zone used to control and interlink with a Heat Pump and a solid fuel stove . Fig 19

Open Vent/ Expansion

Cylinder Heat Lock
Vent

Expansion Tank
Unobstructed Gravity Circuit

ZONE B’ andC’ WILL SWITCH ON AUTOMATICALLY WHEN NRG LINK CALLS

Zone B

Pressure Vessel

Zone A

AAV

DHW

P3 AAV

Zone C

P4 Safety Valve
Boiler

Fill Point

NRGZone 4

Strainer

P2

P1

If the DHW cylinder is insulated a heat leak radiator must be added to the gravity circuit

Heat Lock Loop
Control Thermostat

Open Cold Feed
Solid Fuel Stove
Safety Valve

Example – 4 zone NRG Zone used to control and interlink with a Oil/Gas Boiler and a solid fuel stove
15

DESIGN ASSISTANCE SKETCH PAD
NRGLink
55ºC Pipe Thermostat
Brooklodge East, Glanmire, Co Cork, Ireland, T45Y018
[T] 00 353 (0) 21 4355728 Email: info@nrgawareness.com Web: www.nrgawareness.com
16

References

• NRG Awareness

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