FAQ

A heat pump can be added to an existing heating system to create a hybrid system. When adding a heat pump to an existing system it is important to be aware of the limitations of the heat pump. A heat pump runs at much lower temperatures than a traditional boiler. Therefore existing radiators will have a lower output when heated by a low-temperature heat pump. This can be accounted for by installing new and larger radiators, or by simply having the boiler take over when it gets too cold for the heat pump to heat the house with the existing radiators. When keeping the existing radiators the heat pump will still heat the system for big portions of the year, just not the colder winter days. 

When designing a hybrid system the heat pump and boiler mustn't run at the same time. Due to the high-temperature difference between the two appliances, the heat pump will shut down if the water from the high-temperature boiler gets to it.

 
We recommend using the NRG Zone manifold to interconnect the heat pump, boiler and heating zones. We also recommend using the NRG Lex 3 with the Hybrid Control Module (HCM) addon to control the system and make sure that the boiler takes over from the heat pump when it is supposed to and to make sure that the boiler and heat pump aren't running at the same time.
 

A solid fuel stove is categorised as an uncontrollable heat source. Therefore it must be installed on an open vented system to prevent any pressure from building up. It is also important that the stove has a heat lead radiator on its gravity circuit to dissipate any excess heat.

If the stove is being added to an open vented heating system it can be added directly. We recommend using an NRG Zone manifold to tie the stove in with the existing boiler and heating zones.

If the stove is being added to a sealed heating system a device is needed to transfer the heat from the stove's open vented system to the sealed heating system without mixing the water or different pressures. Our NRG Link is designed for this application and comes pre-plumbed, pre-wired and pre-insulated. We usually use the NRG Zone together with the NRG Link to simplify the design and installation of the system,

The standard NRG Zone comes in 3 sizes. NRG Zone 4, NRG Zone 5 and NRG Zone 6. The number indicates the number of connection pairs. If you have a system with 1 boiler, 2 radiator zones and 1 domestic hot water zone, you need an NRG Zone 4. If you have a system with 1 heat pump, 2 underfloor heating manifolds and 2 radiator zones, you need an NRG Zone 5. As you can see, the number of inputs and outputs has to be the same or smaller than the number in the NRG Zone model name.

We recommend designing systems with a pair of spare connections, this is to make it easier for the homeowner to add a heat source or heating zone in the future if they are building an extension or want to add a renewable energy source. Simply remove the plugs and you are ready to add the new zone/appliance.

For the NRG Zone 5 and NRG Zone 6 we also have versions with 1 1/4" connections on the sides instead of the usual 1". These would be suitable for systems with higher-than-normal flow rates. For example, heat pumps greater than 14 kw and boilers greater than 30 kW.

We also make large bespoke manifolds for commercial projects.

A heat pump can replace a boiler in an existing heating system. When adding a heat pump to an existing system it is important to be aware of the limitations of the heat pump. A heat pump runs at much lower temperatures than a traditional boiler. Therefore existing radiators will have a lower output when heated by a low-temperature heat pump. This can be accounted for by installing new and larger radiators or using underfloor heating.

It is also important to be aware that the heat pump operates with a smaller temperature differential between flow and return, this means that it needs a higher volume of water to deliver the same amount of energy as a boiler. Before replacing the boiler with a heat pump you have to confirm that the existing pipes are large enough to handle the higher flow rates, or you have to replace the pipes. In some cases, it might be enough to just use a larger circulation pump to overcome the resistance of the undersized pipes.