Natural gas instantaneous water heaters are very efficient household appliances that can supply heated water for household needs indefinitely. And although their operating principle has not changed since the invention, the design has undergone many improvements. Users will not be bothered to study the device of a modern gas column to successfully operate it, and sometimes repair it on its own.
The device of modern gas columns
At the moment, in the distribution network you can buy two types of domestic water heaters:
- The most common option is geysers with an open combustion chamber (atmospheric). In them, air for burning gas comes from the room in a natural way, passing through the opening at the bottom of the apparatus and the viewing window.
- With a closed combustion chamber (otherwise - turbocharged or supercharged). Here, air is forced into the combustion zone by a fan.
First, we will analyze the device for more than simple atmospheric columns, consisting of the following basic elements:
- metal case;
- gas burner with igniter;
- finned heat exchanger with a casing and a coil of copper;
- automatic gas valve with a regulator of combustion intensity;
- mechanical water unit with safety valve;
- ignition system;
- a diffuser with a pipe at the end for connecting the chimney;
- water and gas pipes extending from below and ending with connecting fittings.
Column ignition systems are used in several types: piezoelectric and electric from batteries, a hydrogenerator or a home electrical system.
In the water heater diffuser, where the combustion products are collected, a draft sensor is installed, connected by wires to the gas valve. A flame (ionization) sensor, also associated with this valve, is placed directly in the combustion zone. Below is a diagram where the atmospheric gas column device is shown in detail:
Now about how the turbocharged version of the water heater with a closed combustion chamber is arranged. By design, it is similar to atmospheric, but has the following differences:
- Instead of a conventional manual burner, a step or modulation burner is installed, changing the flame intensity in automatic mode.
- Combustion air is supplied by a fan, whose performance is regulated by the controller (electronic unit).
- The ignition system is fully automatic, operating from the mains or hydro generator.
- The column device provides for maintaining water heating at a set level (for example, up to 60 ° C). This is monitored by a separate temperature sensor connected to the controller.
The turbocharged gas column diagram is shown in the figure:
How does a hot water column work?
The task of water heaters of this type is to react by turning on the burner to open a hot water tap anywhere in the house and ensure that it is heated to the desired temperature. To describe in detail the principle of operation of a gas column, we list the sequence of processes taking place in atmospheric models:
- At the first stage, the user sets fire to the igniter located in the viewing window and directed towards the main burner.
- After the tap is opened, a flow of water appears in the DHW system, and the pressure rises. The device of the water unit (colloquially - frogs) provides that the membrane is triggered and moves the rod connected to the gas valve.
- From the action of the membrane of the water unit, the valve opens the fuel supply to the main burner, which is immediately ignited from the igniter or directly from the spark electrode. The user can manually adjust the power of the flame using a crane on the front panel.
- Water entering the heat exchanger of the gas column begins to heat up even in the coil made around the copper casing. This principle of operation avoids the formation of condensate on the tubes due to the difference in temperature of cold water and the flame of the burner.
- Heated water goes to consumers. After closing the tap, the frog membrane retracts the stem, the valve shuts off the gas supply and the burner device dies, and heating stops.
This is how most of the inexpensive atmospheric gas water heaters with a constantly burning igniter work, which do not need to be connected to the mains.
This principle of operation is inherited from instantaneous water heaters of an old design. In more modern models, there is no wick that never fades, which is why the heat exchanger casing from the front is destroyed over time. For example, the Neva gas column diagram, originally from St. Petersburg, provides for electric ignition from batteries at the time of the appearance of a water flow.
The operation of pressurized water heaters is based on the automatic maintenance of the water temperature set by the user. Ignition is carried out from the mains or from a hydrogenerator built into the water supply system and generating electricity when a flow occurs. Further heating is controlled by a controller that focuses on the temperature sensor. It changes the fan performance and combustion rate depending on the temperature of the outlet water.
What to consider when choosing a water heater?
A household gas water heater is not a boiler for heating and it is difficult for an ordinary user to choose it by power. It is much clearer when it comes to the amount of heated water. This value is indicated in the technical passport of the product of any manufacturer and is expressed in liters per minute when heated at 25 ° C.
For clarity, we present a table with data on water heaters of the Russian brand Neva, showing the dependence of productivity on the heat output of the unit:
Reference. Columns for the needs of domestic hot water are inferior in efficiency to gas heating boilers from 3 to 5 percent. If the efficiency of the atmospheric heater is about 88%, then the efficiency of the same water heater is 84%. But to experience this difference is impossible in practice.
When choosing a device for heating water, you must first determine its performance. Further we suggest following simple recommendations:
- If your budget is limited and electricity is often cut off in your area of residence, then a simple, non-volatile atmospheric type model is just what you need. The ignition system - from a piezoelectric element or on batteries, they last quite a long time (2-3 months with intensive work).
- In most apartments, atmospheric columns cannot be installed due to the lack of chimney channels, and the removal of combustion products into ventilation shafts is prohibited. No problem, buy a turbocharged water heater with a coaxial chimney facing the street right through the wall. Just determine the place of exit of the pipe and coordinate it with the neighbors. More information about connecting chimneys to geysers is described in this article.
- In our conditions, when the water supply networks are worn out, it is better not to install devices with the ignition from the hydro generator. The latter can quickly fail due to poor water quality and water hammer in pipelines. To protect the generator, you will need a water gear, and this is an additional cost.
- Try to pick up modern modifications of devices where the ignitor does not burn around the clock.It slowly but surely consumes gas, destroys the front wall of the heat exchanger and smokes on the front panel.
The choice of the appropriate manufacturer is yours, but there are still brands whose products are time-tested and have proven themselves in work:
- Junkers (Junkers), aka Bosch;
- Beretta (Beretta);
- Electrolux (Electrolux);
- Neva;
- Vector.
Common Malfunctions
Like any gas-using equipment, the water heater must be serviced and repaired by a specialist in this field. But there are a number of simple malfunctions that the owner of a private house or apartment can fix on his own. Most often, flowing water heaters have the following problems:
- The igniter is not set on fire.
- The wick burns, but after the valve is opened, the main burner does not turn on or ignites, but immediately extinguishes.
- Inadequate heating of water is observed.
- Water begins to drip from the bottom of the case.
There may be many causes of the listed symptoms, but we will indicate the most obvious ones that the user can eliminate with his own hands.
It often happens that the ignitor does not ignite due to a banal reason - the batteries (batteries) are exhausted.
The cause of burner attenuation may be:
- lack of draft in the chimney channel;
- malfunction of the draft sensor or a violation of the contact in its wiring;
- leaky membrane of the water node;
- filter clogged inlet (if any).
The low temperature of the outlet water, which happens after several years of operation, is usually associated with the appearance of scale in the heat exchanger and it will have to be washed. But drops of water from under the housing indicate a leak in any connection, safety valve or the heat exchanger itself. The reason is the overheating of the device at the time of turning off the water.
A malfunction with overheating is inherent in atmospheric geysers. The mechanism is this: when water shuts off sharply and the burner shuts off, the heat exchanger remains hot, boiling occurs in it and steam forms. If the situation is constantly repeated, then the steam eventually breaks out, breaking the weakest seal. Hence the recommendation: in such devices, you must first turn off the gas, and then shut off the water.
Conclusion
Inexpensive instantaneous water heaters with an open combustion chamber have a fairly simple design and a minimum of electronics. Knowing the internal structure of the geyser, the homeowner will service the unit without problems, and if necessary, eliminate minor malfunctions. Turbocharged columns are more complicated, but here the user can independently perform part of the work. For example, clean the electrodes or replace the worn membrane of the water unit.