Frequent operation and shutdown of the heating boiler is a fairly common problem. It occurs in different boiler models from different brands. The main thing is to detect and eliminate it in time. We suggest looking at why a gas boiler often turns on and off and what to do if the unit is not working correctly.
Malfunction is often the result of incorrect installation or failure to follow operating instructions. If you see that the equipment begins to randomly turn on/off at high frequency, you need to carry out diagnostics and repairs. Otherwise, the service life of the equipment will be greatly reduced due to rapid wear of parts.
The most common reasons for incorrect operation of heating equipment
Even systems from leading manufacturers can malfunction for various reasons: Navien, Ariston, Bosch, Vaillant, BAXI and others. A common reason why the Navien boiler often turns on and off (like models from other brands) is incorrect installation. The system starts turning on/off every 5-7 minutes or even more often.
If you see that the operation occurs more often than normal, this is a reason to contact a specialist. He will be able to more accurately diagnose the problem and find the answer to why the malfunction occurred.
Here are some more common reasons:
- The model was chosen incorrectly. For example, if a model with too much power is installed for such premises. We have repeatedly said that you need to choose units with a power reserve, but not too much. Usually +10% of the recommended power is enough.
- The circulation pump is not installed correctly. If the coolant does not move as expected, this can also cause operational errors.
- The specified temperature range is incorrect. Modern models of heating equipment make it possible to accurately indicate the temperature range that they must maintain - to prevent overheating of the room and its hypothermia. If the owner sets these values incorrectly and the temperature difference is too small, this may be the root cause why the boiler often turns on and off.
- There is no thermostat installed in the room, and the operation of the equipment is adjusted according to the temperature of the coolant. This solution does not provide an objective assessment of the room temperature and the system does not work correctly. It is more efficient and reliable to install a thermostat.
Most of these problems are not critical and difficult to solve. But if you do not pay attention to them, the system will wear out much faster due to incorrect operation and will require replacement. And this is already expensive. We will talk about these problems and their solutions further.
Excess power
A powerful wall-mounted or floor-standing gas boiler in a small room is overkill. First of all, it's expensive. And secondly, power must be calculated accurately, and not in excess. Too much power is not recommended, as is insufficient power. If you cannot perform power calculations yourself, we recommend contacting a specialist who will do everything.
By the way: if you install a unit of insufficient power, there may not be a problem with frequent switching on/off, but condensation will constantly collect in the chimney. Clogging and wear of system elements accelerates. Plus, it will be impossible to fully heat the premises.
We have already written how to calculate the power of a heating system for a home. The choice is influenced by many factors:
● climate in the region by season; ● total area of heated premises; ● materials used to build the house and the quality of insulation; ● type, sizes of windows and doors, etc.
Check the instructions for how often your boiler should be activated. These values differ for different models. You should be wary not only of too frequent shutdowns, but also of its different frequency - after five minutes, after three, then again after five (the intervals may be different).
If your boiler has excess power, this is not a reason to buy a new one. There are several ways to solve this issue:
- Install 4-way mixing valves in the hydraulic system. This is the most effective method, but it is also the most expensive.
- Lower the burner. This method is only applicable if a multi-stage burner is installed.
- Install and connect the boiler. This way you will reduce the boiler power and at the same time provide the house with hot water.
Well, in order to prevent such reasons for frequent switching on and off of a gas boiler, it is easier and cheaper to initially carry out calculations and select equipment.
Circulation pump installed incorrectly
Natural circulation may not be efficient enough, which is why installing a pump is completely justified. In particular, for large houses with several floors. Any violation during installation can lead to malfunctions of the equipment - the unit will go out, may clap and show other signs of malfunction.
Excess power
Under no circumstances should you install a boiler of greater power than required for a particular room. It is necessary to accurately calculate the required power. After all, a lack or excess of power can negatively affect the operation of the equipment. Therefore, if you were unable to independently calculate the required power, then you can turn to specialists who will correctly carry out all the calculations.
But in order to determine the power, it is not enough to know the area of the heated room. The following factors influence the power value:
- House wall material;
- Material of windows and doors;
- Room area;
- Climatic conditions of your area.
But there are many resources on the Internet where you can find online power calculations. You can use them for an approximate calculation.
But if you bought a heating boiler and noticed that the power is much more than required, then you need to solve this problem. First you need to find out how often the boiler can turn on during normal operation. In order to ensure normal operation for a boiler with increased power, it is necessary to install a four-way mixing valve in the hydraulic system. This option will show excellent results. But you will also have to spend a considerable part of your funds.
If your appliance has a multi-stage burner, then you can try the method of lowering the burner.
Another way is to connect the boiler to the boiler. In this option, in addition to reducing the power of the gas heating boiler, it will be possible to provide the house with hot water supply. In order to determine the power of a single-circuit and double-circuit heating boiler, it is necessary to use different schemes. It is better to choose boilers with the minimum power required to heat your home.
In order to correct the problem of frequent boiler switching on, as well as reduce fuel consumption, you can use a thermo-hydraulic distributor instead of a mixing valve. It costs a lot more, of course, but the result is much more effective.
Differences between Navien Ace and Navien Delux
Navien Delux is a modified model that replaced Navien Ace. Navien Delux Coaxial is a series of boilers with two heat exchangers with a power from 10 to 30 kW with a closed combustion chamber and forced smoke removal using a turbine. The manufacturer notes the following features of Navien Delux:
Frost protection system. Unlike boilers from other manufacturers, in addition to automatically turning on the burner when the temperature drops below 6 degrees, at temperatures below 10 degrees the boiler ensures continuous movement of the coolant by activating the circulation pump.
Fan with variable speed. Navien Delux boilers are equipped with a turbine with adjustable blade rotation speed depending on the readings of a special air pressure sensor. This ensures an optimal gas-air mixture ratio and increases boiler performance.
The heat exchanger is made of stainless steel. By using a fan with variable rotation speed and increasing combustion efficiency, it became possible to replace the copper heat exchanger with a stainless steel heat exchanger, which certainly has a significantly longer service life.
It is also noted that the boilers are protected from the influence of mains voltage surges by a special protective chip and the ability to operate at low (up to 4 mBar) pressure of main gas and water. In other words, the manufacturer tried to make a product that is maximally adapted to the worst operating conditions.
Navien Delux Coaxial device
The word Coaxial in the name of the boiler means the use of coaxial chimneys (pipe in pipe). This system is convenient in that only one pipe is used to supply air to the combustion chamber and remove exhaust gases, which can be led from the room to the street by the shortest route. In general, the boiler is not fundamentally different from products from other brands. You can note the convenient location of the expansion tank and the non-standard location of the fan - it is located below the burner.
It is noteworthy that Navien boilers do not have a built-in control panel. All adjustments are made using a separate control panel. The remote control is also equipped with a temperature sensor and displays various information about the operating status of the equipment and will report a malfunction with an error code. A special feature of Navien is also the presence of an air pressure sensor, which not only performs a draft check function, but also sends data to the control unit for portion control and determines the presence of reverse draft. If there is excess pressure in the chimney, for example due to wind blowing, the gas supply to the burner will be stopped and the boiler will stop.
At the bottom of the boiler there are inlets and outlets of the heating and hot water circuits, a make-up tap, a drain plug, a cleaning filter and a safety valve for relieving excess pressure.
Operating principle of the Navien boiler
The operating principles of modern gas boilers are almost the same for all manufacturers, the only differences are in the configuration of the equipment and the internal arrangement of the actuators. The flow diagram of water in the boiler is shown in the figures. The Navien boiler works either to maintain the required temperature in the CO, when heated water from the first heat exchanger is pumped by a circulation pump in a large circle, or in the DHW preparation mode. The DHW mode is a priority, which means that if it is necessary to heat the water, a special three-way valve switches the circulation to the DHW plate heat exchanger, and the coolant flow through the heating circuit is blocked. The signal to switch the boiler to the DHW preparation mode comes from the flow sensor located on the hydraulic unit with the make-up tap.
Checking the heating system: pipes, radiators, circulation pump
If the boiler power meets the requirements, you should pay attention to the elements of the heating system (all valves and thermostats, radiators, pipes); perhaps something is blocking or slowing down the movement of the coolant, make sure there is no air.
In systems with forced circulation, the cause may be the circulation pump. Firstly, in order to operate the boiler in vacuum mode, it is recommended to install it on the supply side (provided that the pump is designed for a temperature of 110-115°C). Secondly, it is worth trying to increase its speed; perhaps the speed of movement of the coolant is not enough and it lingers for a long time in the boiler heat exchanger.
Navien malfunctions
A gas boiler is a structurally simple device, but to ensure safe operation, any such units are equipped with automatic safety equipment, which serves to prevent serious accidents when operating errors occur. Almost all physical processes occurring during the operation of the unit are controlled by various sensors, information from which is sent to the control unit and continuously processed.
For the convenience of diagnosing and troubleshooting, information is provided to the user on the control panel display in the form of codes, which can be used to determine which specific system the malfunction has occurred and what checks can be carried out to eliminate it. Next we will look at the most common errors of Navien boilers in more detail.
Problems with closed-type turbocharged equipment
Sometimes when installing a new chimneyless apparatus, the flame periodically goes out. In this case, you need to check the components and parts. The problem is detected by the following factors:
- ignition of the igniter is accompanied by periodic attenuation - this indicates a failure of the thermocouple, which affects the operation of the valve. It is produced in the form of a copper tube with a bimetallic piece at the end. When different metals come into contact, the voltage increases to 20-45 W. This problem keeps the gas valve open. The thermocouple must be replaced with a new one; it cannot be repaired;
- breakdown or clogging of the traction sensor - the flat part is combined with the fuel valve. When the leading contacts are closed and the burner is ignited, a fire occurs - this indicates the need to replace the sensor. Oxidized areas of contacts can be cleaned with sandpaper with fine abrasives;
- if the circulation pump malfunctions, it is necessary to carry out a complete diagnosis of the unit and replace it;
- A yellow flame is due to the fact that the jet is clogged. You can clean it if you have experience working with gas appliances.
Most of the reasons can be eliminated with your own hands, however, this will require some knowledge and a lot of time.
Navien boiler error 02
Error 02 is caused by the heating circuit flow sensor located at the outlet of the main heat exchanger. If nothing prevents the movement of water in the CO circuit, after turning on the pump, the sensor contacts close and the signal is registered by the control unit, otherwise error 02
.
The following main reasons can be identified:
low pressure in the heating system (to control the pressure, Navien boilers are equipped with a dial pressure gauge located on the front cover - you need to check and, if necessary, feed the system to 1.2-1.5 bar)
failure of the flow sensor (to check, measure the resistance of the sensor before and after turning on the pump)
no circulation in the heating circuit
control board is faulty
Lack of circulation means that for some reason the coolant cannot move normally through the heating pipes. Obstacles can be: clogged cleaning filters, freezing of a section of the pipeline, closed taps around the perimeter of the heating system, the presence of an air lock or a malfunction of the pump.
To remove air, you can try to start the boiler in a special test mode, after first opening the air vent valve on the pump. To activate the test mode, you need to turn off the boiler and move switch No. 1 on the DIP-Switch block of the board to the ON position. We will discuss the testing of actuators in more detail in a separate article.
We recommend watching a video in which one of the users simulates error 02 on a Navien boiler:
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Navien boiler error 03
In gas boilers, the presence of a flame on the burner is checked by a special sensor - an ionization electrode. The operating logic of the unit is to continuously check for the presence of a flame after opening the gas valve. Symptoms of error 03 on Navien boilers can be divided into two groups:
unsuccessful attempts to ignite (no flame appears)
ignition occurs, but the flame goes out
If ignition does not occur, you need to check:
gas pressure at the inlet and outlet of the gas valve (can only be carried out by a qualified specialist using special equipment - a differential pressure gauge)
condition of the ignition electrodes (compliance of the gap with the manufacturer’s standard, contamination of the electrodes). The normal distance between the electrodes is 3.5-4.5 mm.
integrity of the insulation of the electrode power wire (you can visually verify that the spark breakdown occurs specifically on the body of the gas burner, and not somewhere else)
correct setting of the boiler power on the DIP switch (valid if there is a problem during the first start of the boiler or after replacing the electronic board)
presence of voltage on the ignition transformer
Error 03
on the Navien boiler will also appear when combustion is unstable (intermittent flame) or if the control unit is unable to detect the presence of a flame. In this case, you need to make sure that the connection between the ionization electrode and the control board is reliable, check that the boiler is grounded and that there is no contamination on the electrode. Unstability of combustion can be caused by an increase in fan speed, so you need to make sure that the yellow hose going from the turbine to the APS sensor is securely connected and not damaged.
If during the checks it was not possible to normalize the operation of the boiler, diagnostics of the boiler board, repair or replacement will most likely be required. We recommend watching a video in which one of the users simulates error 03 on a Navien boiler:
More rare technical reasons why a gas boiler often turns on and off
Low pressure in the gas line
It's no secret that domestic gas pipelines may allow interruptions or a decrease in gas pressure. In the event of a failure, the burner simply goes out; in more expensive boilers, the automatic system extinguishes the flame as soon as it, due to the low gas supply pressure, drops to a critical level at which the burner may burn out. If the problem is temporary, this may be the issue.
There is also a possibility that the meter may break or become clogged, and it may produce a characteristic noise. If the measuring device is malfunctioning, contact a specialist; it is prohibited to carry out any work yourself.
Clogged or frozen chimney
Standard chimneys, in the absence of regular maintenance, are characterized by clogging with soot, dust from the street, and particles of construction waste. Lack of draft can lead to characteristic cyclical operation of the boiler; it is enough to clean the chimney yourself or contact the utility service.
Freezing of the coaxial (side) chimney can also limit the draft of turbocharged and atmospheric boilers. Combustion products in the form of vapors form condensate, which settles on the chimney. In severe frosts, above -15°C, this contributes to critical icing, which affects traction. If advanced models with a self-diagnosis function inform the owner with a corresponding error, then simpler models turn on cyclically and immediately turn off.
The solution is quite simple - knock off the icing and clean the chimney. To prevent the problem, it is worth installing a special anti-icing chimney design.
Backdraft
Occurs when the calculation of the height or cross-section of the chimney is incorrect. It also often happens during strong gusts of wind in boilers with a horizontal flue. When the flame is blown out by reverse draft, the gas control of the boiler turns off the burner for safety reasons, and then lights it again.
What to do if the gas boiler blows out in a strong wind
Voltage fluctuations or failures
An extreme reason for the malfunction of the boiler can be fluctuations or interruptions in the voltage supply (respectively, if the boiler is volatile). In the first case, in the absence of a voltage stabilizer, some models of gas boilers may interrupt operation and start again, if this is provided - the corresponding error is displayed on the screen.
A similar situation occurs during a short-term power failure, which is typical in our conditions and is not at all uncommon. The problem can be avoided by installing and connecting a UPS (uninterruptible power supply), which will be able to ensure the constant operation of the boiler for some time after the power supply is turned off.
Navien boiler error 10
This error is related to the smoke removal system of the gas boiler. Combustion products must be removed; for this purpose, the boilers are equipped with a fan. To control the operation of the fan and determine the presence of permissible draft for boiler operation, a differential relay is used, which is connected to the turbine by two plastic tubes. When the fan is running, a vacuum is created, the relay closes, and the boiler functions normally.
Reasons for error 10
may be a clogged chimney, the presence of reverse draft, or incorrect connection of the air pressure control sensor to the fan. For the latter case, you need to check that the yellow tube is connected to the bottom of the fan, and the transparent one is connected to the top, and the tubes themselves are not damaged, deformed or condensation inside.
Increased resistance in the chimney can occur due to direct gusts of wind or blockage of the chimney (bird nest or cobwebs, freezing in winter). That's right, the location of the chimney should be taken into account the direction of the winds of a particular region at the design stage and the chimney should not be installed on the leeward side of the house.
We focused on the most common malfunctions of Navien boilers, but in fact there are significantly more error codes. Methods for checking and troubleshooting are the topic of a separate article. For convenience, here is a summary table of codes with a brief description:
I once wrote here about this boiler. Following the problem with the high temperature of the batteries, which has not yet been resolved, the following one appeared. During DHW operation, the boiler turns off spontaneously and immediately turns on. In 10 minutes of work it can glitch about 5 times. I called a technician - they washed the heat exchanger, swapped the temperature sensors of the circuits - to no avail. The master shrugged his shoulders and assumed there was a problem with the board. I also noticed that if you set the temperature higher, it turns off much less often, or does not turn off at all. What's the matter?
Excessive power as the most common cause
In a simplified form, the required boiler power is calculated based on experience: for every 10 m 2 of an average house with a masonry of 2 bricks and a ceiling height of no more than 2.7 m, 1 kW of thermal power of heating equipment is required. It is also recommended to take into account a reserve of 15-20% so that the boiler does not work at the limit or the heat transfer is sufficient during the most severe frosts in the region.
This calculation method is sufficient for any typical private home. For example, for a house with an area of 200 m2, a boiler unit with a capacity of 22-24 kW is required.
How to calculate the required boiler power Individual calculation, formula and correction factors
The boiler lights the main burners, which quickly, in 2-5 minutes, heat up the missing few degrees of coolant temperature and turn off. And since modulation (power adjustment) of the flame is not provided for by the design of the burners, nothing can be done at the level of boiler settings.
