DIY gas heater setup and repair: a guide for water heater owners

Vasily Borutsky
Checked by a specialist: Vasily Borutsky
Author: Angela Kravets
Last update: October 2019

Isn't it true that having spent money on installing a column, I want the house always to have hot water of a given temperature? But even the most modern equipment fails. What to do if an icy stream pours from a tap or vice versa - boiling water?

Can I repair gas water heaters with my own hands or is it better to call gas workers? Let's decide together what problems with water-heating equipment can be solved independently. We will analyze and list for what problems a wizard is necessary.

From the article we presented, you will learn how to restore the gas unit to working capacity and how to set it to the optimal mode. We will introduce you to the typical design of gas-fueled appliances and their typical operational errors.

The design of gas water heaters

To repair any equipment, you need to know its design features.

For domestic needs gas water heaters of 3 main types are used:

  • cumulative;
  • flowing;
  • combined.

Most popular gas instantaneous water heaters. Abbreviated GPVN. GOST they are defined as instantaneous water heaters. In such devices, water is heated only when the tap is turned on.

Water heater circuit
The standard GPVN scheme includes many elements grouped according to the functions performed: gas path, combustion path, water circuit, etc. For example, burners belong to the gas path, and the heat exchanger to the combustion path

Technical requirements for domestic instantaneous gas water heaters equipped with atmospheric burners are established by GOST R 51847-2009. Their classification is also given there.

Features of diagnostics and repair

Manufacturers usually indicate in the accompanying documentation that repairs to the GPVN should only be performed by service company employees.

In accordance with the requirements of labor protection, such work is performed by adults who have undergone vocational training and are licensed by the State Industrial Supervision Authority.

If nevertheless you decide to eliminate minor defects yourself, you should be aware of the explosiveness and suffocating effects of liquefied and natural gas, be prepared for emergency situations, and be able to use fire protection equipment.

Please note that the same problem in the operation of the equipment can be caused by different reasons. For example, you open a hot water tap, but the gas water heater does not turn on. This can be due to dirty filters, damage to the controls, and about a dozen other reasons.

Difficulties in diagnosis are encountered by both home masters and representatives of service companies. But gas workers have experience and professional equipment, which greatly facilitates and accelerates the solution of the problem. A home foreman is often armed only with a screwdriver and adjustable wrench.

Before embarking on an independent repair, adequately evaluate your resources, weigh the pros and cons. This will help save time and avoid risks.

Battery compartment
Do not forget that all repair operations for which it is necessary to remove the front panel of the housing or completely remove it must be carried out by gas workers from the organization with which a contract was concluded for the maintenance and supply of gaseous fuel. In case of self-intervention, the manufacturer’s warranty is void

If the warranty period has long been exhausted, you can perform the simplest steps to restore the functionality of a gas water heater yourself. When identifying the causes of malfunctions, it is not necessary to immediately dismantle and disassemble the device.

Act from simple to complex, first check:

  • whether shut-off valves for water and gas are open;
  • whether there is gas in the cylinder (if the column is running on liquefied fuel);
  • Are the batteries installed correctly in the battery compartment and is there a charge.

This principle works for most common faults. In the future, we will not return to it, believing that you have already performed the initial diagnosis, but you could not get by with a little blood.

Why does water heat up poorly?

Over time, the burner channels accumulate dust, soot is deposited on the edges of the heat exchanger. As a result, real heat output drops and lukewarm water runs from the tap. Related problems: the column does not turn on, the burners smoke and spontaneously go out.

Scum on pipes
Water entering the heat exchanger from a well or water supply system contains magnesium and calcium salts. When heated, they settle on the inner surfaces of the heat exchanger in the form of scale

The thermal conductivity of the stainless steel and copper from which the heat exchangers are made is 45 and 401 W / m2 × K, respectively. These indicators vary slightly depending on the grade of metal. The thermal conductivity of scale is much less - only about 0.2 W / m2× K.

This means that even a small precipitate on the walls of the heat exchanger leads to a decrease in heat transfer. As a result, the time for heating the water increases. Deposits reduce the diameter of the passage, which reduces the flow of water.

How to clean the heat exchanger?

At home, the predominantly chemical method is used. It is universal and suitable for both collapsible and welded / soldered heat exchangers. Special detergents are used that do not react with the metal, but dissolve carbonate deposits.

Before cleaning, you must:

  • shut off the gas and water supply;
  • drain the remaining water by turning on the tap;
  • remove the protective cover;
  • disconnect the supply pipes and wires;
  • remove the heat exchanger.

Pour warm water into a deep basin with the addition of dishwashing detergent. Place the heat exchanger and the gas burner unit in the basin. Use a soft brush to clean the soot from the radiator grill, rinse the parts with a stream of clean water, not forgetting the channels through which gas is supplied to the burner.

Heat exchanger flushing
To remove scale, install the heat exchanger in the basin upside down (down the radiator and up the inlet and outlet of the tube). Pour anti-scale agent into the tube. After dissolving the scale, drain the liquid and rinse the heat exchanger thoroughly. Reassemble and connect

The plate heat exchanger can be carefully disassembled before cleaning. In this case, do not miss the opportunity to examine it and assess the condition. If the wear of the plates is significant, it is best to replace them immediately. With a small layer of scale, instead of special liquids, you can use ordinary table vinegar or a solution of citric acid.

The washing time varies from 30 minutes to a day or more, depending on the properties of the detergent and the thickness of the deposits. After eliminating contaminants, the thermal performance of the column should correspond to those indicated in the passport.

Limescale Prevention

The use of faucets in a water supply system involves the mixing of cold and hot water. This method leads to an acceleration of scale formation. It is recommended to use a separate faucet for hot water, and a gas flow regulator will help increase or lower its temperature.

If, when the water is heated, its temperature often rises above 60 degrees, scale will form faster. Do not fill the bath with boiling water for subsequent dilution with cold water. Correctly configure the device, and water of a comfortable temperature will come immediately from the tap. Recommended temperature for bath and shower is in the range of 37-42 degrees.

The rapid accumulation of soot leads to prolonged heating of the water at the maximum flame of the burners, poor draft of the chimney, incomplete combustion of the gas and the presence of impurities in it.

What to do if the column does not turn on?

You opened a hot water tap, but there is no spark and the instantaneous gas water heater does not ignite? It is possible that carbon deposits formed on the electrodes of the candles. In many models, these parts can be cleaned through the viewing window using a brush on a long handle.

Spark plug

Sometimes water heaters do not work due to weak water pressure. Check the filter and, if necessary, clean it or replace it, rinse the heat exchanger. Open the stopcock completely. If the pressure remains weak, contact the management company (Housing and Utilities).

Kitchen column

Difficulties with the ignition of the gas column are often caused by damage to the elastic membrane located at the beginning of the water circuit. When the valve is opened, a pressure drop occurs, due to which the membrane bends and acts on the gas valve through the stem. As a result, the gas enters the burners.

With repeated bends, the membrane wears out, stretches, breaks and no longer performs its functions properly. Losing elasticity or integrity, it is not able to press on the stem with sufficient force. The gas valve does not open or does not open fully.

Due to lack of fuel, the water heater does not work. The membrane replacement algorithm is as follows:

  • shut off water and gas;
  • removal of the casing;
  • disconnection of branch pipes and wires;
  • membrane removal and replacement;
  • reassembly.

Upon completion, using a soapy solution, the tightness of the demountable joints is checked.

The burner goes out spontaneously

A water heater with an open combustion chamber is switched on normally, but its nozzles go out during operation. This problem may be due to a lack of air, which is taken directly from the room where the device is located.

With tightly closed plastic windows, air exchange with the street is difficult, which leads to the operation of the protection system and the flame of the burner goes out.

Chimney blockage
Blocking the operation of a gas boiler can occur due to poor flue gas removal. A common cause of this problem is a chimney blockage.

Open the window, wait about 10 minutes and turn on the column. If it goes out again, check the path of the combustion products. For atmospheric burner water heaters these are common chimneyswith natural traction.

Gas workers check traction with an anemometer. The device allows you to determine the amount of air passing through the chimney. Home craftsmen use thin paper, which must be cut into strips about 2 cm wide and about 20 cm long and brought to the chimney inlet at a distance of 5 cm.

First turn off the column, remove the exhaust pipe and open the window. If the paper strips are not carried away by the air flow and do not touch the entrance of the chimney, then it is time to clean it.

Piezo ignition system
The ignition device does not work if the gas supply is interrupted, the spark plug is clogged or smoked. Other causes include breakdown of the ignition device transformer or violation of the electrical circuit connected to it.

Please note that during leaks, gas builds up in the discharge shafts. Therefore, do not try your luck by checking cravings with a burning match, candle or lighter.

The burner works with the valve closed

Have you turned off the hot water tap, but the burner is not going to go out? Most likely, the stem of the gas or water circuit stuck. This is the case when you can not do without specialists.

But first of all, it is necessary to block the gas access to the apparatus by closing the shut-off valve on the gas line, and only then call the service department.

Leakage through detachable connections

The stopcock is installed on the cold water inlet pipe using a threaded union nut. A pipe through which hot water enters the plumbing system is connected to the heat exchanger pipe in a similar way.

Detachable connections
All detachable connections of the water circuit are sealed with gaskets made of asbestos-free paronite, Teflon or oil and petrol resistant rubber. Gasket wear leads to poor sealing of joints and leaks

Before replacing the gasket, the column turns off, the water in the water system is shut off, the nuts are unscrewed, the worn gaskets are removed and new ones are installed in their place.

The water heater is very noisy

Serviceable gas equipment is very quiet and this is one of its advantages.

Fan column
Closed combustion chamber gas water heaters are equipped with fans that pump the air required for combustion and exhaust flue gases

An increased noise level indicates an excessive flow of water in the heat exchanger or its overheating.

Measure the temperature of the water in the tap and, depending on the result, adjust the flow of water or gas in the direction of decrease.

Security issues

To meet the safety requirements, manufacturers equip them with a variety of sensors. If the burner is extinguished for some reason and the gas continues to flow, the air-gas mixture may explode.

This development helps prevent a flame detector. Between its control electrode and the burner flame, ionization currents arise, on the basis of which discrete signals are formed. If there is no flame, shut-off valves are triggered and the gas supply stops.

If the sensor is installed in such a way that the electrode touches the parts of the burner or is located too far from the flame, its correct operation becomes impossible. This causes the speaker to turn off. To solve the problem, just change the location of the electrode.

Water heater repair

To control the water temperature, an overheat sensor is installed on the heat exchanger tube. Usually it is a thermal relay with bimetallic heat-sensitive elements.

When the water temperature approaches the boiling point (85 ° C), the shape of the heat-sensitive elements changes, which leads to the opening of the electrical circuit of the power supply of the electronic unit and the column turns off.

Failure of the overheating sensor, rupture of the electric circuit leads to premature shutdown of the column, even if the water does not have time to heat up.

Excluding other possible causes of the malfunction, with the help of a multimeter check the integrity of the conductive conductors of the electrical circuit. If there are no gaps, check the sensor and, if necessary, replace it with a working one.

To do this, disconnect both wires from the sensor, unscrew the fastening screws that fix the device to the heat exchanger. Now it remains to remove the old sensor and install a new one.

Pressure testing of a water circuit

After repairing the gas water heater with disassembling the water circuit, it is necessary to check the tightness of the pipes and joints. The most effective method is crimping. Fill the circuit with waterwhose temperature is from 5 ° C to 25 ° C. The air temperature in the room should be above 0 ° C.

Using a manual or electric pump, the pressure in the circuit is raised to the test value. Stand for at least 5 minutes, controlling the pressure using two pressure gauges pre-installed at two points in the system.

If the pressure has not fallen by more than 10%, the water circuit is sealed. Otherwise, the diagnostics of the malfunctions are performed again, and after their elimination, a second leak test is performed.

The test pressure is 1.5-2 times higher than the working pressure indicated in the passport of the water heater. The exact values ​​for different types of columns are easily found in GOST R 51847-2009. They cannot be exceeded, so during pressure testing it is necessary to carefully monitor the operation of pumping equipment.

Temperature and water flow control

Speakers equipped with an electronic control unit and a display for displaying relevant information are gaining great popularity. Thanks to this technical solution, setting the gas water heater is to select the desired mode, which is then automatically maintained.

Columns with a mechanical control system are equipped with rotating handles located on the front of the case. One of them serves to adjust the gas flow, the second regulates the flow of water. A number of models also have a third handle - “winter / summer”.

At low pressure in the water supply network, the water flow knob is set to a minimum. If the inlet water pressure is normal, the handle can be set to maximum.

Devices for adjusting the gas column
Adjustment is carried out with the crane open, taking into account the regulatory parameters specified in the operating instructions. Errors lead to the extinction of the burner flame

The temperature of the water entering the tap from the column directly depends on the gas flow. To reduce or increase it, the gas flow rate is accordingly reduced or increased.

The adjustment process is as follows:

  • close the gas valve;
  • set the gas flow knob to a minimum;
  • open the gas valve;
  • turn on the hot water tap;
  • give a few minutes to heat;
  • measure the temperature of the water coming from the tap;
  • if the water is not hot enough, turn the gas flow knob one step;
  • continue adjustment until the required water temperature is reached.

If the heating capacity of the water heater does not allow you to heat the water to the desired temperature even with the maximum gas flow rate, screw the water supply shut-off valve slightly. The volume of water entering the column will decrease, and its temperature will increase.

The combination of a minimum water flow rate and a maximum gas flow rate can lead to overheating, triggering of the protection system and shutting down the burner. In this case, you need to slightly change the settings to achieve the optimal balance.

Display for data monitoring
The new generation gas water heaters are equipped with electronic displays that display the functions of the device, the parameters and performance required for tuning

In winter, the water temperature in the water main can drop to 4 degrees, and in summer it can rise to 20 degrees or more. In order to avoid overheating or underheating of water during seasonal temperature changes, many modern columns are equipped with an additional handle. It must be timely installed in a position appropriate to the time of year.

Conclusions and useful video on the topic

Owners of flowing water heaters sometimes encounter difficulties when firing up - they fail to light a glow plug the first time. The problem can be solved independently:

If the solenoid valve fails, the gas supply to the burners stops, the security system is activated and the column is turned off. You can check the health of this component yourself:

Owners of gas water heaters just need to know the device design in order to timely understand what the problem may be and to prevent its occurrence. It is worthwhile to familiarize yourself with typical malfunctions that occur during operation. It is possible that you can eliminate simple irregularities in your work yourself.

Please write comments in the block below, post a photo on the topic of the article, ask questions. Tell us how you coped with the problems of a gas water heater with your own hands. It is possible that site visitors will be able to take your advice.

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