To successfully choose a gas column you need to find answers to the following questions:
- What is a gas dispenser?
- What manufacturing capacity should a gas dispenser have?
- What water pressure a gas dispenser is designed for?
- What is gas dispenser’s ignition type?
- What type of heat exchanger does a dispenser have?
- What are the safety devices a gas dispenser is equipped with?
- Any additional functions?
The relevance and importance of these questions is given below:
1.What is gas dispenser?
This device has long been well known to our consumers – an in-line water heater with gas with manual ignition is still often found in houses, especially old buildings. In the past, such devices were produced in hundreds of thousands per year. However, a gas dispenser is not only the past, but also the future, because such water heaters have a number of advantages, first of all - it is economical: for all economic troubles gas is still the cheapest source of heat in the house.
While a liter of the water heated by the dispenser costs several times cheaper both in comparison with water coming from the electric heater and from the centralized HWS systems. It is convenient, that the dispenser, which is an in-line heater, does not require the presence of a boiler, which occupies a considerable space, and therefore is compact. The promptness of the hot water supply ("switched on and got ") is also a plus in comparison with storage heaters, which will require at least an hour to heat up your "own" volume of water. In this case, the capacity of the storages is limited by the volume of the boiler, and the dispenser heats the amount of water that you need while there is cold water and gas in the system.
2. What manufacturing capacity should a gas dispenser have?
The manufacturing capacity of the dispenser can be indicated both in kW, and in l/min.
Typically the manufacturing capacity is indicated in l/min. As a rule, this value is reduced to a certain temperature difference when the water is heated, which is 25°C. For example, the manufacturing capacity of the dispenser is 10 l/min. This means that when the temperature of the water entering the dispenser is 10°C, heating the water to a comfortable temperature of 35°C, the dispenser is able to pass 10 l/min. This value is conditional: a smaller flow of water corresponds to a larger heating temperature.
The necessary flow of hot water can be estimated by the number of points of water extraction (mixers). On average, a flow of 6-7 l/min corresponds to one mixer.
Thus for a standard apartment with one mixer in the bathroom and one mixer in the kitchen, the minimum recommended typical size is 10 l/min.
Below is a table on which you can easily determine the recommended typical size.
3. What water pressure a gas dispenser is designed for?
First of all, it is necessary to pay attention to the minimum pressure at which the dispenser is switched on. It must also be indicated on the nameplate. A low water pressure is a special characteristic of the houses built within the 60s-70s. Therefore, if the manufacturer's declared value is above 0.15 bar, there may be problems when the dispenser is switched on when there is insufficient pressure.
It is also important that the materials and connections of the water heater are strong enough to withstand the hydraulic shocks that can periodically occur in the water supply system. A hydraulic shock is a short-term pressure increase in the system. Its consequences may be damaged joints and leakage of water from the dispenser as a result. The value can be considered as a value of 11-12 bar that is sufficient to withstand periodic hydraulic shocks.
4. What is gas dispenser’s ignition type?
Here are three possible options:
Piezo-ignition. The name is not easy, as is the method of ignition, which involves working with hands, which is not always suitable for modern residents. If it does not make it difficult to come up and press the button, then why not choose this type of device? Only it is necessary to take into account the location and the fact that the gas consumption in this case will be greater, since the igniter remains on after ignition.
Ignition from batteries. This option is convenient because it is automatic. This means that the ignition is switched on automatically when the tap is opened. The same happens with the fan and gas supply. The energy source is batteries. Convenient and simple.
Ignition from a hydroturbine. The option is also automatic. The difference is in the source of energy, which is provided from an electric generator of small size, a drive from a hydro turbine. However, this type of device should only be selected if the water pressure is at least 0.35 atm.
5. What type of heat exchanger does a dispenser have?
Virtually all gas dispenser heat exchangers are made of copper, but there are cheap models with a less durable aluminum heat exchanger.
Of course, it is advisable to opt for a copper heat exchanger.
When choosing a copper heat exchanger, it is important to pay attention to the places of adhesion. Black dots and lines say that, most likely, the manual soldering of the heat exchanger was used. With such soldering, errors are possible, and during the operation of the dispenser, superheated areas can appear in the heat exchanger, which lead to burn-out and leakage of the heat exchanger after 1-2 years of operation.
6. What are the safety devices a gas dispenser is equipped with?
For safe use, the gas dispenser must be equipped with basic safety devices such as:
Ionization flame control.
Ionization electrode, located, as a rule, near the igniter or near the main burner. If there is a flame on the electrode, an ionization current is generated that keeps the gas supply valve. In the absence of a flame, the supply of gas ceases.
Protection against lack of traction in the chimney.
Typically, it is a temperature sensor installed in the flue gas manifold on the top of the column. When the chimney is blocked, the combustion products leave the column through special channels, while heating the temperature sensor. If there is such a leak, the dispenser stops gas supplying and switches off.
In the event that for some reason the temperature in the heat exchanger exceeds a certain value close to 80°C, the dispenser stops gas supplying and switches off.
7. Any additional functions?
Many people want the installation to have additional parameters that will be useful in certain conditions. Gas dispensers can have the following functions:
Available screen, the water temperature is displayed on it.
Availability of decorative pictures on the panel of a dispenser, thanks to such function the device will easily be entered in an interior.
In conclusion, we want to add a few tips for the competent operation of the gas dispenser:
- Observe the requirements and regulations given in the manufacturer's instructions.
- Check the hardness of the water and compare it with the one specified in the manufacturer's instructions. Hard water leads to deposits of salts in the heat exchanger, which leads to its destruction. If the water is hard, then it is desirable to use the means to soften it.
- Try to adjust the comfortable temperature of hot water immediately at the outlet of the dispenser. Thus, the dispenser will operate at lower temperatures, and less deposit will form in the heat exchanger.
- Recommended frequency of gas dispenser maintenance is 1 time per year.