BS EN 303-6:2019 pdf free.Heating boilers.
6.2.2 Instantaneous type 6.2.2.1 Maximum temperature of the domestic hot waterThe boiler is operated at the nominal domestic hot water heat input with a domestic water supply pressure of 2 bar.Starting with this 2 bar supply pressure, the pressure is progressively reduced until the burner is extinguished. The water outlet temperature is measured continuously with a low inertia thermometer. The maximum temperature is measured and shall satisfy the requirements of 5.2.2.1.6.2.2.2 Overheating of the domestic hot waterThe boiler is operated at the nominal domestic hot water heat input, where appropriate. The water rate and any water temperature control are adjusted to obtain the maximum water temperature at the nominal domestic hot water heat input.After the boiler has operated for 10 mm, the hot water delivery tap is turned off quickly. After 10 s the tap is turned on quickly and the highest temperature at the centre of the flow, as close as possible to the boiler outlet, is measured by means of a low inertia thermometer. The boiler remains in operation until it has again reached its steady-state condition. The same measurements are made during similar operating cycles, but with the time that the draw off is stopped increased each time by 10 s, until the maximum temperature is obtained.It is checked that the requirement of 5.2.2.2 is met.6.4.1 Instantaneous and storage types — Specific water rate The boiler is operated at the nominal domestic hot water heat input with an inlet water pressure of 2 bar. The domestic hot water temperature is adjusted, where possible, to obtain an average temperature rise as close as possible to 30 K which permits the nominal domestic hot water heat input to be obtained. Before the test, the boiler is in the “summer” operating mode, at thermal equilibrium, without any draw off. For storage type boilers, the setting of the domestic hot water thermostat is adjusted to 65 °C or the value stated by the manufacturer for boilers with integral, non-disconnectable tanks. If by design, the 65 °C temperature cannot be achieved, the test is carried out at the closest possible temperature to 65 °C. The first draw off is carried out no earlier than the second controlled shut down of the burner and lasts 10 mm. The temperature and the water rate are recorded. The test follows the sequence:
— water delivery of 10 mm duration; — 20 mm period of no water delivery; — further water delivery of 10 mm duration. BS EN 303-6 pdf download.