BS EN 89-2000 pdf download.Gas-fired storage water heaters for the production of domestic hot water.
7.16.2.1 General
The water heater Is supplied with one of the reference gases for the category to which it belongs,
The water heater is fitted with the longest combustion air supply and combustion products evacuation ducts stated by the manufacturer. The tests may be carried out without the terminal or fining piece.
The CO concentration is determined as stated in 7.12.2.
7.16.2.2 Supervision of the combustion air or the combustion products pressure The water heater is adjusted to the nominal heat input. Measurements are taken at thermal equilibrium.
The CO and CO2 concentrations are measured continuously. By choice of the manufacturer one of the following tests is conducted:
a) the voltage at the fan terminals is progressively reduced, It is checked that the requirement of 7.16.1.2 a) is met;
b) with the water heater at ambient temperature, the minimum voltage at the fan terminals which enables the burner to Ignite, is established. Under this condition, the water heater is operated until thermal equilibrium is reached. It is checked that the requirement of 7.16.1.2 b) is met.
7.16.2.3 Supervision of the combustion air or the combustion products rate
The test is carried out when the water heater is in thermal equilibrium, at the nominal heat input, or for modulating water heaters at the maximum and the minimum heat input and at the heat input corresponding to the arithmetic mean of these two inputs. When several rates are provided, supplementary tests are needed at each of these rates.
The CO and CO2 concentrations are measured continuously. By choice of the manufacturer one of the following tests is conducted:
a) the combustion products evacuation duct or air inlet is progressively blocked. The means of carrying out the blockage shall not give rise to re-circulation of the products of combustion. It is checked that the requirement of 7.16.1.3 a) is met
b) with the water heater at ambient temperature, the maximum blockage of the combustion products evacuation duct or air inlet which enables the burner to ignite, is established. The means of carrying out the blockage shall not give rise to re-circulation of the products of combustion. Under this condition, the water heater is operated until thermal equilibrium is reached. It is checked that the requirement of 7.16.1.3 b) is met;
C) the voltage at the fan terminals is progressively reduced. It is checked that the requirement of 7.16.1.3 C) is met;
d) with the water heater at ambient temperature, the minimum voltage at the fan terminals which enables the burner to ignite, is established. Under this condition, the water heater is operated until thermal equilibrium is reached. It is checked that the requirement of 7,16.1.3 d) is met.
7.16.2.4 Gaslair ratio controls
7.16.2.4.1 Endurance
The ratio control is supplied with air, at ambient temperature, in the direction of gas flow. The rate is not to
exceed 10 % of the declared value.
The pressure at the inlet of the ratio control is the highest normal pressure for the water heater category stated by the manufacturer.
If the test is carried out away from the water heater, the ratio control is fitted on a test rig having a fast-closing valve upstream arid downstream of the ratio control and may include a device creating a downstream suction.
The test rig is programmed such that the first valve opens when the second doses and a complete cycle is effected every 10 s.
When the ratio control is fitted on the water heater, the device is subjected to a similar endurance test. At the end of the endurance test it is checked that the requirement of 7.16.1.4.1 is satisfied.
7.16.2.4.2 Leakage of non-metallic control tubes
The water heater is supplied with the reference gas at its nominal heat input.
The requirements of 7.16.1.4.2 are checked under the various situations that could occur, in particular:BS EN 89-2000 pdf download.