Setting and Programming of ELÍZ Electric Boiler Control

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Setting Up and Programming the Controls of the ELÍZ Electric Boiler – A Complete Guide

The ELÍZ electric boiler is a device especially appreciated by owners of family houses and apartments who value simple operation, reliable output, and the ability to precisely set temperatures. Although the installation itself is a job for a qualified electrician (you can read more about that in the topic Installing the ELÍZ Electric Boiler: Procedure and Installation Requirements), setting up the controls is something every user encounters – from the first start-up to seasonal mode changes. This is exactly where most of the questions we repeatedly get from customers come from.

In this article, we'll go through the entire process of setting up and programming the controls of ELÍZ boilers step by step. We'll focus on practical scenarios: the first start-up after installation, setting daily and weekly programs, configuring weather-compensated (equithermal) control, working with an external thermostat, setting protective parameters, and also the common mistakes people make when programming that lead to higher energy costs or uncomfortable heating.

How Control Works in ELÍZ Boilers – Principles Before Setup

Before you start programming, it's important to understand how the control system of the ELÍZ electric boiler works on a basic level. In this respect, an electric boiler is simpler than a gas one – it has no burner, gas valve, or flame modulation. Instead, it regulates output by directly switching electric resistance elements (or PTC heating elements) on and off, or by modulating their output.

Temperature control in the ELÍZ boiler happens on two levels:

Primary control (boiler level): The thermostat in the boiler monitors the outlet water temperature and switches the heating elements on/off according to the set target heating outlet temperature (the so-called set-point). This value is set directly on the boiler's display or via its control panel.
Secondary control (room level): An external room thermostat or controller (e.g. room thermostat, OpenTherm controller, or weather-compensated controller) communicates with the boiler and adjusts its target outlet temperature or switches it on/off directly according to the room temperature.

Combining both levels of control is the basis of efficient heating. The boiler alone, without room-level control, only operates based on water temperature – it has no way of knowing whether it's 15 °C or 22 °C inside the house. That's why properly wiring and setting up a room thermostat can reduce energy consumption by 15 to 25% compared to a boiler without room-level control.

First Start-Up of the ELÍZ Boiler – What to Set First

After installation and filling the system (never start the ELÍZ boiler without water in the circuit!), the first start-up follows. This is the moment when you need to set the basic parameters. Before that, check:

System pressure – for ELÍZ boilers, it should be 1.0 to 1.5 bar when cold. When the system is heated (60–70 °C), it may rise to 1.8–2.2 bar, which is normal.
Expansion vessel setting – volume and pre-charge pressure must match the volume of water in the circuit.
System air venting – air in the radiators prevents circulation and can cause the boiler to overheat.

After the physical check, turn on the boiler. The display usually shows the current outlet water temperature and the basic mode. First steps in the menu:

Setting the Language and Basic Units

Older ELÍZ models come with the interface in Slovak or Czech from the factory. In newer models, such as the ELÍZ EQH 802, you can choose the language from the menu on first start-up. Set the correct language, date format, and time format – these values are essential for the weekly programs to work correctly.

Setting the System Time and Date

Time and date are critical for the weekly program. An error of just one hour can cause the boiler to heat at night instead of in the morning. Procedure on ELÍZ boilers: enter the menu (usually by long-pressing the "Menu" or "SET" button), find the "Time/Date" item, and set the values using the arrow buttons. Confirm by pressing "OK" or "Enter".

Practical note from experience: After a power outage, on some ELÍZ models without a backup battery, the clock resets. If the radiators don't heat up at the right time after a power outage, the first thing to check is the time setting on the boiler.

Setting the Outlet Water Temperature – The Right Value for Different Systems

The outlet water temperature (the so-called boiler water temperature or heating water temperature) is a key parameter. You set it directly on the boiler, and it determines the maximum temperature to which the boiler heats the water in the circuit. An important rule applies here: the lower the outlet water temperature, the lower the energy consumption for the same heat output – but only if your heating surfaces are properly sized.

Specific values for common types of systems:

Underfloor heating: 30–45 °C. This is the most efficient type of system for an electric boiler. At higher temperatures, there is a risk of damaging the floor covering and unnecessary energy consumption.
Low-temperature panel radiators (modern, larger surfaces): 45–60 °C.
Standard panel and column radiators: 60–75 °C. This is a typical scenario in older houses, where cast-iron or steel radiators are sized for temperatures of 70/50 °C (outlet/return).
Maximum temperature of ELÍZ boilers: Most models allow setting the maximum outlet water temperature up to 85 °C, some models up to 90 °C. Normal operation should be lower – the maximum temperature serves as a safety limit, not an operating point.

In boilers with weather-compensated output control (see below), the outlet water temperature changes automatically according to the outdoor temperature, which is the most efficient approach in terms of consumption.

Programming Daily and Weekly Modes

Most ELÍZ boilers allow you to set up a so-called weekly program – a defined schedule of when the boiler heats to the comfort temperature, when the setback (economy) mode is active, and when the system is in frost protection. This is one of the most important features in terms of energy savings.

Comfort Temperature, Setback Temperature, and Frost Protection

Before you start programming, define three basic temperature levels:

Comfort temperature: The outlet water temperature during active heating. It is set according to the desired room temperature and the type of system. For example: if you want 21 °C in the house and have panel radiators, the comfort outlet water temperature will be around 65–70 °C.
Setback (Eco) temperature: The temperature during absence or at night. It is typically set 5–8 °C lower than the comfort temperature. For example: comfort 70 °C → setback 55–60 °C. Important: setback is not the same as turning the boiler off. The boiler still keeps the system warm, just at a lower level.
Frost protection: The minimum outlet water temperature at which the boiler switches on regardless of the program. Usually 10–15 °C. This function remains active even when the boiler is in "off" or "holiday" mode.

Real-world example: A customer had a weekly program set up where on Friday evening it switched to "weekend" mode (comfort all day), but on Monday morning at 5:00, the boiler wasn't able to heat the house up in time for 7:00, when the kids leave for school. Solution: the setback temperature was reduced only to 58 °C instead of 45 °C, and the start of the comfort program was moved to 4:30. The house was reliably warm by 7:00 every time.

Setting Up the Weekly Program on ELÍZ Boilers

The specific menu differs depending on the model, but the general procedure for most ELÍZ boilers is as follows:

Enter the menu by long-pressing the "Menu" button (3–5 seconds).
Navigate with the arrows to "Weekly Program" or "Time Program".
Select a day of the week (Monday–Sunday) or a group of days (Mon–Fri / Sat–Sun).
For each day, set up to 3–6 switching points (times) when the temperature mode should change.
For each switching point, enter the time (e.g. 06:00) and the desired mode (Comfort / Eco / Off).
Confirm each point with the "OK" button.
Once all days are set, save the program (usually a long press of "OK" or the "Save" option).

Setting up the setback mode during working hours (8:00–15:00), when the house is empty, is one of the most effective ways to save energy. In practice, we often find that many customers don't use this option at all and heat at full comfort 24 hours a day. With a well-set program, the difference in monthly consumption can be 20–30% compared to non-optimized operation.

Weather-Compensated (Equithermal) Control – Setup and Curves

Weather-compensated control is a more advanced feature that automatically adjusts the outlet water temperature to the current outdoor temperature. The principle is simple: when it's –15 °C outside, the boiler heats to 75 °C. When it's +5 °C outside, the boiler only heats to 55 °C. The system thus automatically adapts to the conditions and doesn't overheat the house.

Weather compensation requires an outdoor temperature sensor, which is mounted on the north-facing wall of the house (in a shaded spot, protected from direct sunlight and wind). The sensor is connected to the boiler via the terminal block – the exact procedure is in the installation manual of the specific model.

Setting the Weather Compensation Curve

The weather compensation curve defines the relationship between the outdoor temperature and the desired outlet water temperature. On ELÍZ boilers, it is set either directly (you enter the curve points) or via the "curve slope" parameter (Slope), which is usually a number between 0.5 and 3.5.

Low slope (0.5–1.0): Suitable for well-insulated houses with underfloor heating. The outlet water temperature changes slowly with changes in outdoor temperature.
Medium slope (1.0–2.0): Standard radiator heating, average house insulation.
High slope (2.0–3.5): Older houses with poor insulation, cast-iron radiators.

How do you know the curve is set correctly? Observe the indoor temperature at different outdoor temperatures. If the house stays consistently warm (e.g. 21 °C) even at –10 °C outside, the curve is well set. If the house is cooler in freezing weather (e.g. 18 °C), increase the slope. If the house is too warm and you have to open windows, decrease the slope or shift the curve downward (the "curve shift" or "Parallel shift" parameter).

Practical tip: Setting the weather compensation curve is an iterative process. After each change, wait at least 24 hours before evaluating the result. Weather can change quickly, and short-term measurements can be misleading.

Connecting and Setting Up an External Room Thermostat

An external room thermostat is the simplest way to improve the control of the ELÍZ boiler without needing weather compensation. The thermostat measures the temperature in a reference room (usually the living room) and, based on that, switches the boiler on or off, or adjusts its set-point.

Bivalent (ON/OFF) Wiring

The simplest type: the room thermostat has a contact (relay output) that opens the circuit once the desired room temperature is reached, causing the boiler to switch to setback mode or turn off. The ELÍZ boiler has a pair of terminals on the terminal block marked for the external thermostat (TA or RT). Important: when these contacts are bridged (wired without a thermostat), the boiler operates in full mode. When they are open, the boiler switches to setback temperature or turns off, depending on the setting.

Wiring procedure (always with the power switched off and isolated!):

Unscrew the cover of the boiler's terminal block.
Find the terminals marked "TA", "RT", or "Room Thermostat".
Remove the jumper bridge between these terminals.
Connect a two-wire cable (e.g. CYKY 2x1.5 mm²) from the room thermostat.
Set the desired room temperature on the thermostat (e.g. 21 °C).
In the boiler menu, set which mode should activate when the contact is open (setback or off).

OpenTherm Communication

A more advanced way of communication between the controller and the boiler. OpenTherm is a digital protocol through which the controller not only switches the boiler on/off but also directly controls its outlet temperature. This allows modulation – the boiler can operate at, for example, 45 °C instead of a full 70 °C, which saves energy. Not all ELÍZ models have OpenTherm terminals, so it's necessary to check the technical specification of the specific model (for example, for the ELÍZ EQH 802 we recommend checking the current documentation for the model).

Setting Protective Functions and Safety Parameters

The ELÍZ electric boiler has several built-in protective functions that protect both the appliance and the heating system. Some are permanently set at the factory (e.g. the maximum thermostat – STB), while others can be adjusted by the user or a service technician.

Maximum Outlet Water Temperature (STB – Safety Thermostat)

The STB is a safety limit at which the boiler shuts down completely and usually needs to be manually reset. On ELÍZ boilers, this value is fixed (usually 90 °C or 95 °C) and cannot be changed from the standard menu. If the STB trips, check: water flow in the circuit (clogged filter, closed valve), the circulation pump's operation, and system pressure.

Minimum Outlet Water Temperature (Frost Protection)

An adjustable value at which the boiler automatically switches on the heating regardless of the program. We recommend setting it to 10–15 °C for the heating water. In the event of a power outage (boiler not working), the system still has some protection through the expansion vessel and insulation, but a long-term outage in freezing conditions is risky – in such cases, antifreeze mixture in the circuit also helps.

"Holiday" Function – Vacation Mode

Most ELÍZ boilers have a "Holiday" or "Vacation" mode. In this mode, the boiler turns off the normal program, maintains only frost protection (e.g. 10 °C outlet water), and automatically returns to the normal program after the set return date. The setting is in the menu: enter the departure date, the return date, and confirm. A very useful function – you save energy while on vacation and the system remains protected against freezing.

Pump Protection Setting (Pump Kickstart)

Some ELÍZ models have a function that automatically starts the pump once every 24 hours (or 48 hours) even if the boiler is not heating. This function prevents the pump from getting stuck after a longer period of summer inactivity. We recommend keeping it enabled year-round. You can find it in the service menu under "Pump Protection" or "Pump Anti-Seize".

Service Menu and Advanced Settings for Technicians

In addition to the standard user menu, ELÍZ boilers have a service menu protected by a PIN code (usually 0000 or 1234 from the factory, or a code listed in the service documentation). This menu is intended for installers and service technicians, not for regular users.

The service menu is used to set, for example:

The number and output of heating elements (for multi-stage output models)
Thermostat hysteresis (the difference between switch-on/switch-off temperatures) – typically 3–5 °C
Minimum pump run time after the boiler switches off (pump overrun, usually 2–5 minutes)
System type (open/closed circuit, presence of a DHW tank)
Priority settings for combined heating and DHW heating
Reset to factory settings

Unauthorized interference with the service menu can lead to a boiler malfunction or voiding of the warranty. If you're not sure, it's better to contact an authorized ELÍZ service center or dealer.

Settings for a Combined System – Heating + Domestic Hot Water

Some ELÍZ boiler models are also designed to heat domestic hot water (DHW) via an external tank (cylinder). In this case, you need to set the following in the menu:

DHW priority: When the tank needs heating, the boiler temporarily interrupts space heating and directs all output to the tank. This is the most energy-efficient approach.
Desired DHW temperature: Usually 55–60 °C for legionella safety. Setting it below 55 °C is not recommended for hygiene reasons.
Anti-legionella program: Once a week (usually Saturday morning), the boiler heats the tank to 70 °C for 1 hour. This function kills the Legionella pneumophila bacteria. We recommend always keeping it enabled.
DHW wait time: The maximum time the boiler waits before giving priority to DHW, to avoid too long an interruption of heating during severe frost.

To learn more about how to properly size the boiler's output for combined heating and DHW use, read the topic What Output ELÍZ Electric Boiler Do I Need for My House.

Common Mistakes When Programming the ELÍZ Boiler Controls

From our own experience with customers, we know that the following mistakes occur very often:

Incorrectly set time: The program works, but at the wrong time. Always check the time after a power outage.
Setback temperature set too low: Setting the setback to 30 °C may be fine in a well-insulated house, but in an older house it means the boiler has to "pull" the house up from 15 °C in the morning, which uses more energy than gently maintaining 18 °C.
Leaving the TA jumper in place while a thermostat is connected: If you forget to remove the jumper on the TA terminals when installing a room thermostat, the thermostat has no effect – the boiler heats continuously.
Setting the comfort temperature to the maximum: Some customers set the comfort temperature to 85 °C, thinking "the boiler can surely handle it." The house does heat up quickly, but consumption is unnecessarily high and the lifespan of the heating elements is shortened. The correct temperature is the lowest one at which the system maintains the desired room temperature.
Ignoring frost protection during vacations: Turning off frost protection before leaving for vacation in winter is risky. Always set the vacation mode, not a complete shutdown.
Not updating for daylight saving time: ELÍZ models without automatic daylight saving time adjustment need to be manually updated every spring and autumn. Customers often forget this.

You can find more on typical issues and their solutions in the topic Common Faults of the ELÍZ Electric Boiler and How to Fix Them.

Optimizing Settings When Combined with a Solar Power Plant

If you have a photovoltaic (solar) power plant at home, the ELÍZ electric boiler becomes a very interesting appliance for direct consumption of surplus solar energy. The basic logic is: when the solar plant produces more electricity than the household is currently using, it's ideal to direct the surplus to the boiler (heating the heating water or DHW).

For this function, you need:

Measurement of surplus solar production (via an energy manager or smart meter)
The ability of the controller or boiler to respond to an external signal (e.g. an input for a tariff signal or direct control via API/pulse input)
Or a simple solution: setting the comfort phase to the middle hours of the day (10:00–15:00), when the solar plant produces the most

A more detailed guide on combining the ELÍZ boiler with photovoltaics can be found in the article ELÍZ Electric Boiler and Photovoltaics: Is the Combination Worth It.

Resetting Settings and Fixing a Frozen Menu

If something goes wrong while programming, the boiler displays error messages, or the menu stops responding, there are several solutions:

Soft reset: Turn off the boiler from the control panel, wait 30 seconds, and turn it back on. Most frozen screens are resolved this way.
Hard reset (power interruption): Turn off the boiler using the switch on the distribution board, wait 2 minutes, and turn it back on. Note: this usually resets the time setting.
Factory reset: The service menu has a "Factory Reset" option. This erases all user settings and returns the boiler to its factory state. Procedure: enter the service menu (PIN code), find the "Reset" item, confirm. Afterwards, you'll need to set everything up again from the start.

After a reset, we recommend keeping a notebook or a photo of the original settings so you can restore them quickly.

Frequently Asked Questions (FAQ)

Can I set a different program for each day of the week separately?

Yes, most ELÍZ boilers allow you to set an individual program for each day of the week. Some models also offer day grouping (Mon–Fri, Sat–Sun, or Mon–Sun), which simplifies setup if the mode doesn't change during the week. We recommend using individual settings at least for weekends, when the whole family is usually at home and heating runs throughout the day.

Why isn't the ELÍZ boiler heating even though the comfort program is set?

The most common reasons: 1) The external room thermostat has reached the desired room temperature and the boiler is correctly waiting. 2) The boiler's time is set incorrectly – the boiler "thinks" it's setback hours. 3) The room thermostat has dead batteries and its output contact is open, which the boiler interprets as an instruction for setback mode. 4) The boiler is in Holiday mode, which wasn't cancelled after returning. Check these four things in the order listed.

How many temperature switching points can I set per day?

It depends on the model. Basic ELÍZ models allow 2–3 switches per day (switch on in the morning, setback in the afternoon, switch on in the evening, setback at night). More advanced models, such as the ELÍZ EQH 802, usually offer 4–6 switching points per day, which is more than enough for most households. If you need a more complex program (e.g. for a home office vs. living areas), it's better to handle it with a zone system using multiple thermostats.

How do I know if the weather compensation curve is set correctly?

A correctly set curve means the room temperature is stable (e.g. 21 °C) regardless of the outdoor temperature, without the need for manual corrections. Practical test: compare the room temperature on a day with an outdoor temperature of –5 °C and a day with +5 °C. If it's the same and suits you, the curve is set correctly. If the house is cooler in cold weather → increase the slope. If it's too warm in mild weather → decrease the slope or shift the curve downward.

Do I need to readjust the boiler every autumn?

It's not necessary if you have a well-set program. What you should check every autumn: 1) Time and date (including switching to standard time). 2) Whether frost protection is active. 3) System pressure (it may be lower after summer due to evaporation). 4) Radiator venting. 5) Outlet water temperature – you may want to increase the comfort temperature compared to the spring setting. You can find more about maintenance in the topic Maintenance and Servicing of the ELÍZ Electric Boiler: How to Extend Its Lifespan.

Can I control the ELÍZ boiler remotely (via phone or the internet)?

It depends on the model and accessories. Some ELÍZ models have a built-in Wi-Fi module or the option to connect an external smart controller with Wi-Fi connectivity (e.g. via OpenTherm). If the boiler doesn't directly support remote control, the solution is a third-party smart room thermostat (e.g. Hive, Netatmo, tado°) connected to the boiler's TA inputs. This way you get remote control without needing to replace the boiler.

Conclusion: Control as the Basis of Efficient Heating

Properly setting up and programming the controls of the ELÍZ boiler is not a one-time action, but an ongoing optimization process. The initial setup after installation will take you an hour or two, but the result – significantly lower energy consumption, comfortable room temperature, and a longer lifespan of the appliance – shows immediately. From experience, we know that a well-set ELÍZ boiler with an appropriate weekly program and a room thermostat uses 20–30% less energy than an identical boiler without proper control.

If you're also working out how to choose the right model or calculate the required output for your house, we also recommend checking out the topics How to Choose an ELÍZ Electric Boiler: What to Focus on Before Buying and What Output ELÍZ Electric Boiler Do I Need for My House. And if you're switching from an old gas heating system, you'll find useful information in the article Switching from Gas Heating to an ELÍZ Electric Boiler: What You Need to Know.

Do You Have a Question on This Topic?

Can't decide, or are you dealing with a specific situation in your household? Write to us - we'll be happy to help.