The operation of modern heating systems with forced circulation of the coolant directly depends on the voltage supply to the electrical circuit thermal unit.
In the event of an accident in the power supply network, the heating pump and boiler automation are de-energized, which leads to the stoppage of the DHW boiler.
To protect autonomous DHW systems from sudden power outages, redundant power supplies are used. Uninterruptible power supplies (UPS) are the most popular among owners of "autonomous" systems.
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Benefits of uninterruptible power supplies for circulating pumps
It is not hard to imagine which unpleasant consequences will freeze the water in the system in winter. Only one replacement of burst pipes and radiators will cost the owners a pretty penny.
Parametric failures in the electrical network are capable of disabling the boiler electronics. it voltage drop up to 160-170 V (in single-phase units) during peak periods of power consumption, amplitude jumps and alternating current deviations frequency of 50 Hz.
Design UPS or UPS (Uninterruptible Power Supply) is a device with a rechargeable battery and a DC-AC converter (direct current → alternating current). The inverting process of the UPS is controlled by a microcontroller with a crystal oscillator.
The UPS is distinguished from other alternative sources by:
- compactness of devices, which allows the production of products in a tabletop / floor version;
- ease of connection and operation, quiet operation the entire model line of uninterruptible power supplies;
- relative cheapness most headings;
- basic protection of the electric motor and electronics of the autonomous DHW system;
- no maintenance costs during use;
- long service life (with battery recharging): 3-5 years or more;
- minimum time pause or lack thereof when switching "backup power ↔ network";
- almost sinusoidal output voltage with minimal distortion;
- the ability to change the frequency and voltage on the connected load.
UPS types
The uninterruptible power supply, depending on the options supported, provides the following functions:
- automatic switching to be powered by a storage battery (AKB) in emergency situations;
- inversion of constant DC voltage (12V) into the required alternating voltage (220 V) with frequency correction of 50Hz;
- smoothing out power surges and filtering network noise with a duration 10-100 ms;
- stabilization of the "transit" mains voltage in the normal mode.
Reference! All UPSs / UPSs are responsible for transferring the heating pump power to the battery, converting the voltage and filtering line noise. Voltage stabilization is performed only by devices equipped with a stabilizer block.
Exist three kinds uninterruptible power supplies, which are also used to work with circulation pumps of heating systems.
Reserve
The simplest budget models provide only the transition to spare power. Normally the mains voltage goes directly to the boiler without stabilizationby passing one passive surge suppression filter.
Photo 1. A reserve budget UPS can only provide a transition to a spare power supply.
In the event of a mains power failure, parameters exceeding the range values, the switch connects the standard battery in 4–12 ms. The constant voltage of the battery is first fed to the electrical converter, where it becomes variable, and then rises to the required 220 V.
Line-interactive sources
These UPSs are more advanced than standby ones. They feature a built-in voltage regulator that corrects for voltage failures. in the range of 25% of the nominal value. This makes it possible to work at fairly large voltage surges without connecting the battery to the process.
Technically, this problem was solved by installing an autotransformer that monitors the deviation of the alternating voltage from a given value. In devices no sinusoidal correction provided mains voltage.
Photo 2. Line-interactive uninterruptible power supply with built-in stabilizer corrects voltage failures.
Inverter uninterruptible devices
In the multicomponent circuit of these devices, the principle of double inversion is implemented. Serviced boiler equipment, regardless of the state of the network, always powered by a battery.
In the absence of mains voltage, the usual DC → AC conversion similar to standby UPS. Direct current is supplied to the battery terminals for recharging.
Inverter UPSs reproduce stable electrical parameters, this type of device is optimal for supplying heat pumps.
Photo 3. Cyber Power inverter uninterruptible power supply is used to supply heating circulating pumps.
What kind of UPS is needed for the boiler?
The main purpose of the UPS / UPS is to ensure the supply of electricity through the charge of the built-in rechargeable battery. Desktop UPS models are common, but they are more suitable for computers.
Taking into account the provision of starting current, one battery charge is enough for 30-40 minutes of continuous work home DHW network.
To extend the autonomy time up to several hours, it is better to choose such a UPS model, which provides the ability to connect additional external batteries.
Attention! Equipment should be chosen with LT (Long Time) marking... This means that external storage capacities are connected and monitored. Helium accumulators are irreplaceable as additional batteries.
At the same time, uninterruptible power supplies improve the quality of the main power supply, preventing the parameters from going beyond the permissible limits.
In our case, voltage stabilization is acceptable in the range of 220 V ± 5% with frequency maintenance of 50 ± 0.2 Hz.
The difference between a UPS and a backup power source (generator, mini-power plant) is that the device switches to battery mode in 3-10 milliseconds.
In the case of double-conversion UPS, there is no switching delay at all.
The use of the device with such a minimum duration / absence of a "pause" will not lead to a malfunction of the automation or stop the pump of the DHW system.
Important! The boiler circulation pump is sensitive to the shape of the supplied voltage. It is required to select a device that inverts 12 in constant voltage battery to variable 220V 50Hz with a "pure" sinusoid.
The last requirement is indicated by manufacturers in the equipment product cards. It means that the distortion of the sinusoidal current at the output of the UPS / UPS does not exceed 8%... Compliance with this condition will ensure silent operation of the pump and significantly will extend the life of the electric motor.
What to look for?
Most modern heating systems use methane as fuel.But for the system to work stably, it must have a current source that produces a continuous voltage without any interruptions. If the power supply is abruptly turned off, then the coolants will gradually cool down, and this is very unpleasant, since cracks may eventually appear on them in some places - first small, and then larger.
Therefore, carefully monitor the stability of the device!
How to make a UPS for a heating system with your own hands
Assemble yourself an uninterruptible power supply capable of within a few days to ensure the operation of the boiler, the following manual will help.
Required set of components
For independent design of the UPS, such ready-made modules and components are purchased:
- 2 car batteries for 12 V with a capacity of 225 A ∙ h;
- pulse power supply unit (PSU) 28.8 V at 50 A;
- a 28.8 V inverter-converter with a 310 V meander output;
- power resonant filter of higher harmonics 310/220 V
- power cord with plug, pieces of insulated wire, connectors and connectors, housing.
Phased assembly
All components are placed in the case, components are connected in the following order:
- We connect "+" and "-" pairs of batteries with a jumper to a serial battery, free terminals are connected to the output of the switching power supply.
- To these terminals connect the inverter, and we equip the power supply input with a wire with a plug for connection to the network.
- The inverter output is connected to the filter, at the output of which we obtain the voltage 220 V 50 Hz with "pure" sine.
Self service
If you managed to assemble the UPS for the boiler with your own hands, then servicing it more often than not is already easy... You only have to change the batteries at some time intervals and periodically check the integrity of the entire system.
It is better to install the UPS either in the basement or in the semi-basement so that it does not occupy the space of the apartment, but moisture penetration, of course, is unacceptable in any case, so placing it in a small cabinet would be a good option.
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General recommendations for choosing the right UPS
It must be borne in mind that a gas boiler with one circulation pump and an electronic control unit requires up to 300 W power consumption. The UPS must be selected so that the rated power was not less than this value.
To calculate the duration of continuous operation of an uninterruptible power supply, the formula is used:
Time (hours) = Battery voltage (V) x Battery capacity (Ah) / Electric power of the boiler (W). For example, for a device with a battery capacity 150 A ∙ h and tension 12 in continuous operation time is 6 o'clock: 12x150 / 300 = 6.
Precautions and Possible Errors
- First of all, if you decide to make an uninterruptible power supply for the heating pump with your own hands, you need to wear gloves so as not to get an electric shock from bare wires or contacts.
- You should carefully consider the wires - they should not have even minor damage, because a short circuit is very dangerous and can not only harm human health, but also cause a fire.
- For the system, several batteries should be connected (it is best to take 2-4 fully charged ones) and connect them in parallel.
- In no case should you save money and take cheaper devices, since the quality and service life usually turn out to be corresponding to the price.
- Do not connect everything to the device, use it exactly for those devices for which it is designed for its power. However, for computers, as a rule, this power is quite enough, the main thing is that the total power does not exceed the maximum allowable.
- The best choice, as experts advise, will be models with phase-dependent equipment.
