UPS for gas boiler

Modern gas boilers are good because in the presence of normal operating conditions, they work completely autonomously. Human intervention is usually only required to adjust parameters. But for stable operation they need a certain pressure and quality of gas, as well as high-quality and constant power supply. The last task is handled by an uninterruptible power supply for a gas boiler. Their choice and parameters will be discussed.

What is a UPS for

In our country, in winter, heating is indispensable. Moreover, heating is desirable without interruptions and stops - in severe frosts, the system can be defrosted. When organizing the system, it must be remembered that most of modern boilers are controlled by automation, and the movement coolant the system is provided with circulation pumps. All this equipment is powered by electricity.

When creating a redundant power system, it is necessary to install an uninterruptible power supply for a gas boiler (also called UPS, UPS (UPS) or uninterruptible power supply)

Given that power outages are not uncommon in winter, additional measures must be taken to create a redundant power supply. In most cases, they install a UPS - an uninterruptible power supply. Its task is to supply power from rechargeable batteries in the event of a power failure or "subsidence" in the network.

Features of choice for gas boilers

An uninterruptible power supply for a gas boiler must be selected so that it supplies a voltage of the correct shape - as close as possible to an ideal sinusoid. In this case, phase synchronization of the sinusoid is also important.

All these requirements are necessary to ensure the normal operation of the control unit. In most imported gas boilers, automation is assembled on the basis of electronics, and it is demanding on the quality of power supply. To assess how important this requirement is, it should be said that, according to the statistics of service centers, about 40-55% of breakdowns of gas boilers are associated with the failure of the control board. At the same time, boards are almost never repaired. They just need to be replaced.

The block diagram of the UPS connection looks like this.

It is also worth remembering that the failure of the control board due to unstable power supply is a non-warranty case (for almost all manufacturers). So the cost of the board and its replacement have to be paid out of your own pocket. Moreover, many boards are delivered "on order", and this is a few weeks of waiting. How to heat the house at this time is an interesting question ... If you also remember that the cost of the board is about 40-50% of the unit cost, you involuntarily think about purchasing a high-quality and reliable uninterruptible power supply for a gas boiler.

The good news is that for one UPS of sufficient power, you can "add" the rest of the equipment that requires high-quality and guaranteed power supply or you just want to ensure its uninterrupted operation. Most often these are computers, televisions and a couple of emergency lights.

Types of UPS

Today, the trading network offers three types of UPS:

• off-line (on-line);
• on-line (off-line);
• Line-Interactive (line-interactive or line-interactive).

Types of UPS for gas boilers and block diagrams of their connection

Ofline UPS (standby type)

These are the simplest and cheapest uninterruptible power supplies.Off-line from English can be translated as "not in line", which reflects the principle of operation of this device. In an uninterruptible power supply of this type, the upper and lower voltage limits are set, at which the boiler operates normally. As long as the network parameters are within this range, power is supplied directly from the line.

If the voltage becomes higher or lower, the transfer relay is activated, power is supplied through the UPS from the batteries. When the mains parameters return to normal, the relay energizes again, shutting down the uninterruptible power supply. For a gas boiler, such protection is, of course, better than nothing, but when you turn on / off the network, there are significant voltage surges. So the stabilization in this case is not complete - there are no large dips or peaks, but the supply voltage is far from ideal. The second drawback of offline-type UPS is that they cannot correct the shape of a sinusoid.

Scheme of operation of an offline UPS (UPS)

Therefore, offline uninterruptible power supplies for gas boilers should be used only if you already have a stabilizer installed on a scrap or apartment. It delivers the ideal voltage, and the UPS in this circuit simply connects the batteries in the absence of voltage. This scheme is expensive, but creates the normal conditions for the operation of equipment demanding on the quality of the power supply.

On-line UPS (permanent type)

This type is also called double conversion uninterruptible power supply units. All because of the principle of work:

• The AC voltage supplied to the input is converted to DC and used to charge the batteries connected to the device.
• The DC voltage is converted into an AC voltage with an ideal sine wave.

It turns out the power supply is converted twice. This ensures voltage stabilization and an ideal sinusoidal shape.

Scheme of the online uninterrupted service

Online uninterruptible power supplies are connected to the power supply circuit break. While the voltage is normal, the linear power is converted, with a reduced voltage, its deficiency is replenished by charging the batteries; in the absence of power, it is supplied from the battery.

The disadvantage of this equipment is the high price and fast discharge of the batteries, which is due to the fact that it is spent on straightening the surges. However, if you want the best uninterruptible power supply for your gas boiler, buy online type equipment.

Line-Interactive (line-interactive)

The properties and characteristics of uninterruptible power supplies of this type are not as good as those of online models, but not as bad as those of offline units. There are all the same batteries and a switch that connects the UPS when the voltage drops. But for voltage stabilization, there is a special unit - an automatic voltage regulator (AVR in the figure above).

How an interactive uninterruptible power supply works

The disadvantage of line-interactive uninterruptible power supplies for a gas boiler is non-instantaneous switching when the voltage changes. But it is much less than in offline devices, but the voltage is kept constant (within certain limits). This equipment is the best choice, as it guarantees good results at a relatively low price.

Determining the UPS parameters

Determining what type of uninterruptible power supply for a gas boiler you need is not all. You need to know at least two more parameters: the power of the UPS and the capacity of the batteries that it can charge.

An example of the technical characteristics of an uninterruptible power supply for a gas boiler

How to determine the power of an uninterruptible power supply

To determine what power you need an uninterruptible power supply, look for the line "power consumption" in the passport of the gas boiler. On average, it is 150-170 watts.If the system has a second circulation pump, its power consumption must be added to this figure.

Uninterruptible power supplies must be selected according to the power of the connected equipment

For everything to work without problems, a power reserve of at least 20-30% is required. If possible, when choosing a UPS, the result can be doubled - just in case. Sooner or later, you will want to add a couple of devices to the load, since it is really convenient - when, in the absence of electricity, at least something works for you. This will be the minimum capacity of an uninterruptible power supply for a gas boiler.

Determining the capacity of the battery

Many UPS models have built-in batteries. In this case, you do not need to read anything. If the batteries are connected separately, it is necessary to find the line "maximum charge current" in the technical specifications. We do not multiply this figure by 10, we get the capacity of the battery that this UPS can charge. Larger batteries can be connected, but in this case they will not be fully charged, which reduces their service life.

Dependence of the battery capacity and the duration of the boiler operation

How to choose a UPS with built-in batteries? For the battery life you need. The dependence of the operating time on the capacity of the batteries and power consumption is shown in the table. It is generally easy to select an uninterruptible power supply for a gas boiler using it.

Criteria for choosing a UPS for a gas boiler

From all that has been said, the following requirements for an uninterruptible power supply for a gas boiler can be deduced:

• Special UPS with sine wave output voltage are required. Uninterruptible power supplies are not suitable for computers. At the output, they do not give out a sinusoid, but a meander - the voltage is also alternating, but not round, like a sinusoid, but with a cut off top. For computers, such a voltage is not a hindrance, but for the heating system it is not. Such a voltage has a bad effect on circulation pumps - they hum and work in jerks. As a result, the impeller wears out quickly, and the pump has to be changed.
• UPS power is selected with a margin. If possible, it is necessary to double the power consumption.
• It is advisable to choose the type online, a good option is the interactive type.
• The capacity of the storage batteries must be selected so that when the power supply is cut off, the heating can work for several hours (at least). This requirement is not critical if a generator is available. In this case, the battery must hold out long enough for it to start. By the way, this is another reason why you should not install computer uninterruptible power supplies for the boiler - they are designed to operate the equipment for 10-15 minutes. During this time, you can correctly exit all programs and turn off the equipment. These minutes are too short for the boiler.
• It is desirable to have the ability to connect additional external batteries (there must be connectors). This will come in handy if you decide to increase the heating operation time from a backup power source or when connecting other equipment.
  

  Diagram of connecting a gas boiler to an uninterruptible power supply (UPS)

The requirements are not the most stringent, but it is advisable to adhere to them. When connecting an uninterruptible power supply, observe the phasing (the UPS phase must be connected to the boiler phase, zero and minus - with the corresponding conductors). Otherwise, the boiler will not work. It is simple to check the correctness of the phasing: pull out the boiler plug from the network. The boiler must continue to run. If the flame has gone out, check the correctness of the connection, the efficiency of the grounding. If everything is OK, but the boiler is still not working, then your UPS is built without a “zero pass-through”. To start the boiler, you need to connect the N (zero) neutral terminals at the input and output on the UPS. For most boilers, this will solve the problem.But there are some brands of boilers, for example - Buderus (Buderus), which need to set a resistance of 1 to 10 MΩ between the inputs PE and N (ground and zero) (Buderus even offers to buy their proprietary resistor).

Actually, this is all about choosing and even connecting an uninterruptible power supply for a gas boiler.