This document specifies the requirements and tests methods concerning the construction, safety, fitness for purpose, and rational use of energy, as well as the classification and marking of hybrid units.
A hybrid unit is composed of:
- a gas boiler as a heat generator which is able to supply the heat demand in all operating conditions;
- an electrical air-to-water heat pump, as a heat generator, which does not have to meet the heat demand in all operating conditions;
- a control unit (see definition 3.1.10).
A hybrid unit can include the facility to produce hot water, either by the instantaneous or storage principle, the whole being marketed as a single unit.
A gas boiler as part of a hybrid unit covered by this document is a gas-fired central heating boiler from the types C1 up to C9 and the types B2, B3 and B5, according to the classification in EN 1749:2020:
a) that have a nominal heat input (on the basis of gross calorific value) not exceeding 400 kW;
b) that use one or more combustible gases of the three gas families at the pressures stated in EN 437:2021;
c) where the temperature of the heat transfer fluid does not exceed 105 °C during normal operation;
d) where the maximum operating pressure in the water circuit does not exceed 6 bar;
e) which are classified as a gas-fired central heating boiler;
f) which are intended to be installed either indoors or outdoors in a partially protected place;
g) which are designed for either sealed water systems or for open water systems.
This document provides requirements for boilers with known constructions.
NOTE 1 For boilers with any alternative constructions, which might not fully be covered by this document, the risk associated with this alternative construction needs to be assessed.
NOTE 2 An example of an assessment methodology, based upon risk assessment and which covers the essential requirements of the Gas Appliance Regulation UE/426/2016, is given in Clause 11.
This document does not cover all the requi ...