Wednesday Nov 4
It can take a lot for an installer to consider a switch to a new brand of boiler, but ATAG is confident that it’s new ‘A’Series of condensing boilers have enough features and benefits to win over any sceptics. PHAM News takes a closer look at what the boilers have to offer.
The new ‘A’ Series condensing boiler from ATAG Heating UK Ltd, the UK operation of Dutch boiler manufacturer, ATAG Verwarming Nederland BV, is claimed to set new standards of efficiency levels. Efficiencies of 109.7% [EN677J] have been achieved during independent testing at KIWA Gastec. CO2 and NOx figures are also impressive, giving the boiler the maximum 3 points on the BREEAM rating.
The Dutch manufacturer is able to boast long experience of condensing boiler technology, with its core business in the development of wall hung system and combination condensing boilers for both the domestic and commercial markets. The company utilises its own 3115 stainless steel inverted heat exchanger, with water-cooled side walls and smooth direct heat transfer pipes. This enables continuous condensation and low hydraulic resistance, which helps to produce the high efficiency levels and low emissions.
Controls and operation
A number of control options provide the installer with a more flexible installation: 230V ‘switched live’ enables use of existing controls; volt free connections allow volt free programmable room thermostats to be used; Z control, for use with ATAG’s OpenTherm Z controller. Whichever option is chosen, an outside sensor can be utilised, if required.
All the boilers, when in heating mode, modulate from their lowest output (4.4kW) up to the output required at a specific moment. This eliminates the need to ‘range rate’ the heating output and allows for an even increase of the flow temperature.
The controls, when used in conjunction with an outside sensor, will calculate the optimum flow temperature required to bring the system up to the required indoor temperature, which allows the boiler to be kept in condensing mode for much greater periods. As the return temperature will be below the dew point of approximately 53°C, a much greater fuel saving is achieved.
The use of an OpenTherm Z controller increases this fuel saving by up to 10% through close monitoring of the room temperature transmitted back to the boiler. The boiler can then modulate down to accurately set the lowest flow temperature required to reach the required room temperature. Unlike standard room thermostats, which operate with a simple on-off control, OpenTherm controls keep the boiler and room temperature constant, thus avoiding large temperature fluctuations.
The heat exchanger monitors not only the flow temperature but also the return temperature, as 2 NTC thermistors are fitted. This prevents the boiler from operating at an AT of more than 20°C, thus eliminating the risk of ‘kettling’ the heat exchanger due to incorrect flow rates.
A hanging bracket and all necessary plugs and screws are supplied with all boilers and, once the boiler is hung from this bracket, all connections are standard 15 and 22mm copper supplies. Full bore lever isolation valves with built in drain points are also included in the hardware pack and an optional wall spacing frame allows pipework to be routed behind the boiler.
The ‘A’ series boiler comes set for a 60/100mm concentric flue system allowing up to 12m flue runs. Options include a 60mm plume management kit or 2 x 80mm air intake! flue discharge system, which can be increased to 2 x 100mm supplies for up to a 40m flue run. Alternatively, flexible flue liners in 80 and 100mm diameter allow for the air intake to be taken from the void left within the chimney, once the liner has been inserted.
The A’ Series combination boilers operate with an increased input of 20% when in hot water mode. More specifically, the A325EC has a 34.2kW input for hot water and achieves flow rates up to 15 litres/m @ AT of 3 5°C. As well as combi boilers,
available in 20 and 32kW models, the range also includes open vent and system boiler models.
A noteworthy feature of the EC combination boiler is a plate and frame primary heat exchanger fitted in the flue outlet connection inside the boiler’s casing. This allows cold mains water preheating using the hot flue gas before entering the secondary heat exchanger. The increase in efficiency this brings reaches up to lS0o when in hot water mode.
All of the company’s combination boilers have been designed to operate from a solar system as all components are designed to operate at high temperatures. A blending valve can be supplied for installation in the hot outlet, thus enabling the user to set the hot water flow temperature without risk of excessive temperatures reaching the taps.
Recognising the need for a supportive sales and technical service, ATAG has established its own training centres in Chichester and Warwick, a nationwide Select Dealer network and the option of ‘for life’ service contracts. To find out more, please circle the number below on the freepost reader enquiry card inside this issue.