401kW – 2907 kW

The ST-plus is a high efficiency low NOx boiler ranging from 401kW – 2907 kW. It can be fired using oil, gas or both oil and gas using a dual fuel burner. The ST-plus boiler is unique with it's 'e-firing' principle and space saving design.

ErP Directive 

After the 1st January 2018, smaller ST-plus (to 400kW output cannot be supplied even as an identical replacement boiler, other than as a spare part.


The above directive is intended to help improve air quality by limiting emissions from all boilers and generators sized at 1 MW or 1000 kW or above.*

Eventually all boilers and generators will be covered by this directive but IMPORTANTLY any plant that is installed and commissioned after 20th December 2018 will have to comply with emission limit values that have been set and defined for NEW plant or equipment. Boilers installed and commissioned prior to this date will be classed as Existing plant or equipment and will be subject to less rigorous emission limit values and will not require permitting immediately.

Hoval have therefore reviewed the models that will be affected under this new directive to ensure that all boilers likely to be commissioned after this date will fully comply with the new emission limits. This has had some impact on both the models we now offer and some of the maximum outputs stated in our technical data. It is therefore very important that boilers purchased before the directive comes into force are suitable if then commissioned after the implementation date indicated.

*Based on heat input, net calorific value basis.

For further information on the above, please contact Hoval Technical

Low NOx emissions
Low fuel costs
Rapid installation
Easy to maintain