All the Greenstar HE and HE Plus models use the same Aluminum-Silicon heat cell with an extra large surface area. As the flue gases pass through the heat exchanger this extra surface area cools the flue gases to around 55°C whereupon the latent heat within is released and applied to the system. Heat that would normally be lost to the atmosphere.

It is this ability to extract as much heat as possible from the gas it burns that gives the Greenstar HE series an exceptionally high level of operating efficiency. This higher efficiency is recognised within section L of the Building Regulations, subsequently achieving a higher SAP or NHER rating.

Key features of the Greenstar HE and HE Plus Combi boilers include the separate plated domestic hot water heat exchanger, which is guaranteed for 5 years.*

This, combined with the ‘keep hot’ facility, ensures that hot water is delivered instantly to the outlet being operated.

The extra large double pass heat exchanger used in the HE Plus models ensures that the boiler condenses in both HTG and DHW modes of operation. This could result in further fuel savings of up to 10%, Modulating central heating and hot water outputs combined with separate consumer controls, also mean that comfortable temperature levels for both can be set independently of each other.†

*Subject to conditions
†Combi boilers only

Hot water mode
Whenever a hot water tap is turned on the incoming mains water will activate a flow switch which, via the electronic central system, ignites the pre-mix burner. Boiler output is automatically boosted to maximum to heat the incoming cold water as it passes through the heat exchanger. Electronic controls modulate the boiler output downwards to ensure that the hot water temperature remains between 40°-60°C (as set by the consumer).

Keep hot facility
Both the HE and the HE Plus models have an in-built keep hot
facility which will keep the primary water within the heat cell hot. This
will ensure that hot water is delivered instantly to the opened outlet.

Eco mode
With the Eco mode button activated the keep hot facility is
de-energised and the hot water will be heated from cold. A slight
delay should be expected before the hot water is at full temperature
when in the Eco mode.

Central Heating mode
On a Central Heating demand, the boiler will initially fire at minimum
output before modulating upwards to meet the actual system
requirement. Electronics within the boiler continually monitor the
heating flow temperature increasing or decreasing output on
demand. A built-in anti-cycling device makes the Greenstar range
particularly suitable for use on systems with TRV’s (Thermostatic
Radiator Valves).

Modulating Pump
The 40 HE Plus model incorporates a unique modulating pump.

This enables the flow rate through the central heating system to be automatically increased or decreased dependent on demand.

The automatic variable pump offers the following advantages:

* Flow rate through the system perfectly matches system requirement.
* Reduced velocity noise levels when TRV's shut down.
* Tolerant to restrictive systems.
* Electricity saving.
* Auto adjustment ensures boiler stays in condensing mode as much as possible.
* No by-pass required.
* Extra benefits within SAP rating scheme.