Hoval has introduced two new models to its range of high efficiency, low NOx steel shell boilers; the Max-3 E and the Max-3 condens E. Each is available in four sizes in outputs up to 6,800kW in gas and dual fuel options. Key features include return inlets with injection effect to ensure return water is heated evenly – avoiding condensation on the flue surface and extending service life.
A low NOx burner is supplied as standard in both models to ensure compliance with the forthcoming Medium Combustion Plant Directive, which will apply to boilers commissioned after December 2018. This is combined with three-pass technology in the Hoval Max-3 E to reduce emissions even further, with retarders in the third pass tubes to improve heat transfer and efficiency.
The Hoval Max-3 condens E also uses a three-pass heat exchanger design, combined with an integrated flue gas condensing heat exchanger with a large heat transfer surface to increase the rate of condensation. The large tube diameter of the gas heat exchanger reduces hydraulic resistance so that a smaller pump can be used (compared with boilers with a narrower tube).