The selection of gas boiler should be considered in the case of their own conditions, the bedroom area and heating, water, electricity, gas, district, etc., all these should be compared before reasonable choice, so that the heating boiler room can meet the comfort requirements, while ensuring provide adequate hot water to meet the people's daily lives and bathing requirements. Specifically the following points should be considered:

1.Output power of gas boiler
　　Boiler heating load can not exceed the rated output power in the following table, and about 10% safety rich amount should be considered add; domestic hot water production will be based on changes in water temperature rise, see the table below production of hot water
Capacity, domestic hot water flow rate can not less than 2.5 L / min.

2.Type of gas, pressure and air consumption
　　The user's selection must be checked daily capacity should not less than the maximum gas consumption in the following table, otherwise it will affect the capacity of heating. The following table is gas consumption per hour of gas boiler for reference.

3.Gas meter
　　The following table is equipped with a gas meter for reference, you can test gas meter flow value whether it is adequate in the selection, which should not be less than the rated flow value in the following table. Special attention should be paid in using artificial gas low resistance meter, gas meter and the user's traffic is often small. The following table and the gas boiler is only required for the gas meter, if the user has to use other types of gas with a gas appliance, the gas meter must be re-compared to the nuclear and the total air consumption must not exceed the maximum value of the selected flow rate of the gas meter.

4. Flow and head of circulating pumpa)

Because the performance curve of the pump flow and head is corresponding relation (see below pump performance curves on as Grundfos, next to Wilo), by calculating the most unfavorable pipeline radiator heating systems, valves, piping and wall water resistance furnace, etc. and add up the value of the security plus the amount of about 10% of the affluent, this value can be used to determine the value of the pump head H, and then on the pump performance curve Richard H corresponding to this head was flow value Q, flow rate Q less than the rated heating water flow (△ t = 25K) to meet the requirements. Boiler water resistance which hosts small 1mH2O.

5.Water, electricity configuration: water, electrical parameters of the user is not lower than the standard value in the following table.

a) Water pipe connection size: users' water, trachea interface can not be less than the value in the following table. For heating
If the pipe diameter is decreased, the sectional area of ??the pipe becomes smaller, which makes the water flow pipe is large, the
Water resistance tubing with water flow rate of 2 power relations (h = ξQ2), and therefore the water resistance of the pipeline will increase exponentially, may lead to reduced water heating system, seriously affecting the heating effect. For gas pipe diameter decreases, the resistance also appears to increase exponentially, making the air pressure is lower than might be desired nominal gas pressure, especially the use of gas but does not allow users to reduce the diameter.