Common faults of ORAVA electric boilers and how to eliminate them

ORAVA electric boilers belong to reliable and long-term proven solutions for heating of family houses, apartments and small commercial premises. Despite their structural simplicity compared to gas or solid fuel boilers, they are not immune to faults – whether it is component wear, installation errors, limescale deposits or electronic failures. Based on many years of service experience and hundreds of customer cases, we have prepared an overview of the most common faults, their causes and proven procedures for eliminating them – sometimes by yourself, sometimes with the help of an electrician or service technician.

This article focuses mainly on electric boilers with forced water circulation (hot water electric boilers), i.e. models such as ORAVA EK-2003 or ORAVA EK-2004. Where appropriate, we will also touch upon convector models ORAVA VL-202 and ORAVA VL-201, which have a different construction, but share some typical weaknesses of electric heating.

Why does the ORAVA electric boiler fail at all?

Before we get into specific faults, it is important to understand what an electric hot water boiler actually contains and where things can go wrong. Unlike a gas boiler, no fuel is burned here – energy is converted into heat directly in the electric element (heating element, also called "spiral" or "cartridge"). Despite this, the system consists of several subsystems, each of which can fail:

• Heating element (electric cartridge) – direct source of heat, works under current and in water, which is a mechanically and chemically demanding environment
• Circulation pump – ensures water circulation in the system; if it fails, the boiler overheats the water in the primary circuit and the safety thermostat turns it off
• Expansion tank – balances pressure changes when heating water; if it is undersized or damaged, the pressure fluctuates
• Pressure relief valve – opens at excessive pressure (usually at 3 bar); if it is dirty or worn, it starts dripping at a lower pressure or remains closed
• Control electronics and thermostats – regulate temperature and protect the system from overheating; they can fail due to electromagnetic interference, moisture or overvoltage
• Temperature sensor (NTC sensor or bimetal thermostat) – in case of failure, it reports incorrect values and the boiler behaves illogically
• Piping system and seals – water leaks are not an "electric" problem, but lead to pressure drop and subsequent error conditions

Each of these components has its own lifespan, and each can be affected by water quality, installation accuracy or frequency of maintenance. For more information on what and how to check, you can read the article Maintenance and service of ORAVA electric boiler – what and how often to check.

Boiler does not start – does not react to switching on

This is one of the most common complaints that service technicians encounter. The customer turns on the boiler, but nothing happens – no indication, no sound, no water heating. There can be several causes and they need to be systematically ruled out.

No power supply – circuit breaker or fuse

An electric boiler with a power of 6 kW (typical power of models EK-2003 or EK-2004) draws a current of about 26–27 A at 230 V single-phase connection, or 8–9 A per phase at 400 V three-phase connection. If the circuit breaker is undersized or old and worn out, it may trip immediately upon switching on – without any warning. The first thing to check is the distribution board: whether the circuit breaker is lit or in the "off" position. Also check the FI protection (residual current device), which can also react – for example, due to moisture in the boiler cabinet.

Solution: Set the circuit breaker to the "on" position. If it trips again immediately, the boiler or wiring is at fault – call an electrician. Never replace the circuit breaker with a higher type without an electrical analysis – this is dangerous. More about the correct dimensioning of the electrical connection can be found in the article Installation of ORAVA electric boiler – procedure, requirements and what the electrician must do.

Tripped emergency thermostat

Every electric boiler has so-called emergency (safety) thermostat, which disconnects the heating element when a dangerous temperature is reached (typically 95–105 °C) and remains in the "disconnected" state even after cooling down – unlike the operating thermostat, which resets automatically. The emergency thermostat must be manually reset by pressing the button (usually a red button hidden under the cover or accessible through a hole with a pin). This situation occurs when the pump fails, when all thermostatic heads are closed at once, or when the water level in the system is low.

Solution: Find the reset button of the emergency thermostat (see the schematic in the installation manual), press it, and check why the overheating occurred. If the situation repeats, the problem is in the circulation or temperature – do not just keep resetting it.

Control board failure

The control electronics of electric boilers are sensitive to overvoltage, humidity, and voltage fluctuations. After a storm or a power outage, it may happen that the board no longer communicates properly with the sensors and the boiler simply "stops". Some models allow a soft reset by disconnecting the power for 30 seconds. If that doesn't help, the board must be diagnosed or replaced.

Boiler is humming, but water is not heating up or heating up too slowly

The boiler is working, the pump is running, but the radiators remain cold – or they heat up much slower than they should. This is a frustrating situation because the electricity meter is measuring consumption, but the heat is not coming into the room.

Scaling of the heating element with limescale

This is by far the most common cause in areas with hard water – and hard water is common in Slovakia (values above 20 °dH are standard in many regions). A layer of limescale acts as a thermal insulator: even a 2 mm layer of scale increases energy consumption by 15–20 %, and with 5 mm layers, consumption can be 40–50 % higher than with a clean element. In addition to higher consumption, limescale causes cracking and popping sounds during heating (thermal stress in the scale), and ultimately leads to the destruction of the heating element – the element overheats in areas covered with scale and burns out.

Solution: Descale the heating element using acid (typically a 5–10 % solution of citric acid or special descaling agents for heating systems). Procedure: close the water inlet and outlet, disconnect the element, immerse it in a descaling solution for 2–4 hours, then rinse it. If the element shows visible damage (pits, corrosion, cracks), it must be replaced. Preventively, it is advisable to install a water softener or a filter at the boiler's inlet.

Closed or dirty thermostatic heads

In practice, it happens that the customer sets the thermostatic heads on the radiators to the minimum (1 or 0) – for example during a holiday – and forgets to open them after returning. The boiler starts, the pump is working, but the water has nowhere to go, the system overpressurizes, and the emergency thermostat stops the boiler. Or the thermostatic head gets stuck (wax or sand inside) and remains permanently closed.

Solution: Check whether all heads are at least partially open. If a head is stuck, remove it and try to manually move the valve stem – sometimes just gently pushing and turning is enough. If the valve stem is permanently stuck, replace it.

Worn or jammed circulation pump

The pump in an electric boiler works continuously (or with long intervals) for many years. Bearings wear out, the rotor can jam due to deposits or from prolonged inactivity (a typical problem at the beginning of the season after summer shutdown). The pump may "whine" (dry running, air in the system) or completely stop rotating.

Solution: First step: bleed the system – open the air vent on the pump or on the radiators. If the pump is not running, try to remove it and manually turn the rotor with a flat screwdriver (there is usually a slot on the pump shaft). If that doesn't help, the pump must be replaced. A standard circulation pump (Grundfos, Wilo, DAB in class A) costs 60–150 € and replacement is relatively simple.

Boiler displays an error code or the indicator light is blinking

Modern electric boiler models from ORAVA display error codes on the display or signal a fault with a blinking LED. Without the user manual, interpreting these codes can be puzzling. Here are the most common situations:

Error code related to temperature (overheating)

The boiler detects a higher temperature at the sensor than the set maximum safe value and enters a protective state. This can be a real overheating (pump failure, closed valves) or a sensor fault. You can diagnose the temperature sensor NTC with an ohmmeter – the resistance changes with temperature (typically 10 kΩ at 25 °C, decreasing with increasing temperature). If the resistance shows no values or is extremely low/high regardless of temperature, the sensor is damaged.

Error code related to pressure

Almost all hot water boilers have a pressure sensor (pressostat or digital pressure sensor). If the pressure drops below 0.8–1.0 bar (depending on the setting), the boiler stops and reports a fault. Low pressure most often means: a water leak somewhere in the system, an empty expansion tank, or the system was bled without subsequent water refill.

Solution: First visually inspect the entire piping – floors, connections, radiators, safety valve. If you don't find an obvious leak, check the expansion tank (the pre-charge in the membrane should be 0.5–0.8 bar in a cold system). Refill the water using the filling valve to 1.2–1.5 bar (when cold). If the pressure drops quickly again after refilling, there is a leak that needs to be located and repaired.

Error code for pump failure

Some boilers equipped with a flow sensor or feedback from the pump can detect that the pump is not running or is running dry. In such a case, the boiler stops and displays the corresponding code. Proceed as described in the pump diagnosis above.

Boiler is dripping or leaking water

A water leak from an electric boiler is a problem that needs to be addressed immediately – water combined with electricity is dangerous, and leaks damage building structures. Possible leak locations:

• Pressure relief valve – if it is dripping at normal pressure (1.0–1.5 bar), the valve is worn or clogged. Replacing the pressure relief valve costs a few euros and is a routine 10-minute repair. If it is dripping at pressure above 3 bar, the system has a problem with the expansion tank or is overheating.
• Seals at connections – after years of operation, rubber seals (O-rings, flat gaskets) age and harden. Replacing the seal is simple, but the system must be depressurized and the water drained from the respective circuit.
• Heating element – corrosion can create a hole directly through the element. In this case, the solution is to replace the entire heating element.
• Condensation – not every moisture on the boiler surface is a leak. In a cold room, air humidity can condense on the surface. Check whether the "water marks" come from drops dripping from above or are a surface dew point.

Uneven heating – some radiators cold, others hot

This is a classic problem of unbalanced systems. The electric boiler is working properly, but heat is distributed unevenly in the building. Causes:

Hydraulic system imbalance

Water in the hot water system seeks the path of least resistance – it flows through branches with lower hydraulic resistance, i.e., shorter or wider pipes. Radiators on the shorter branch are hot, while distant ones remain cold. The solution is hydraulic balancing of the system – setting the control valves (balancing valves) so that the flow is properly distributed. This is a job for an experienced plumber with a flow meter.

Air in radiators

Air is the enemy of every hot water system. If air accumulates in a radiator, it takes the space that hot water should occupy, and the radiator is cold at the top. Bleeding is a simple operation: with a warm system, open the bleed valve (usually at the top of the radiator) until water starts to flow out, and then close it. After bleeding, check the pressure and add water if necessary.

Improperly set thermostatic heads

If the heads in some rooms are set too low, the water flow through these valves is minimal, which may not cover the heat loss of the room. For information on proper setting, see the article Control and temperature setting of ORAVA convectors – how to properly control heating.

Pressure fluctuations in the system – too low or too high pressure

The operating pressure of a hot water heating system should be 1.0–1.5 bar in the cold system and up to 2.0–2.5 bar at operating temperature (70–75 °C). Deviations from these values indicate a problem.

Too low pressure

If the pressure regularly drops (you have to add water once a month or more frequently), there is a leak somewhere. Even a small leak of 0.5 dl per day will cause enough water loss over a month to lower the pressure. Check the safety valve (it may be dripping into the drain hose unnoticed), connections, and the expansion tank (a cracked membrane causes the tank to fill with water instead of maintaining pressure, and the safety valve opens with every heating cycle).

Too high pressure

Pressure that rises above 2.5 bar at normal operating temperature usually indicates a problem with the expansion tank. Either the tank is too small (undersized in the original design), has a cracked membrane, or the pre-charge pressure in the tank is too high. The pre-charge pressure in a membrane tank is checked with a standard pressure gauge (a Schrader valve like on car tires), and for a standard system it should be 0.5–0.8 bar.

Noisy operation – cracking, gurgling, humming

Noises from the boiler or piping are not just unpleasant – they are diagnostic signals. An experienced technician can tell a lot about the condition of the system from the nature of the sound:

• Cracking and clicking when heating – typical sound when there is a high level of scale on the heating element. The scale cracks during thermal expansion. Solution: descaling the element.
• Gurgling or bubbling in the pipe – air in the system. Bleed the radiators and system bleed valves (usually also on the manifold, if it exists).
• Humming from the pump – either air in the pump (bleed the pump) or worn pump bearings (replacement). If the humming is new and appeared after years of quiet operation, the bearings are at the end of their life.
• Knocking in the pipes when turning on/off – "water hammer" when thermostatic valves close suddenly. The solution is a damping device or replacing with valves that close more slowly.
• Squeaking from the thermostatic head – water flows through the valve insert at too high a differential pressure. Adjust the flow at the control valve or install a differential pressure regulator.

Problems specific to ORAVA VL-201 and VL-202 convectors

Convectors such as ORAVA VL-201 and ORAVA VL-202 have a different construction from hot water boilers – they heat air directly using an electric resistance element, without water. Typical faults are therefore different:

Convector does not heat or heats only partially

Electric convectors have one or more heating elements that can be switched individually (power levels). If one element burns out, the convector still works, but at a lower power. Diagnosis is simple – measure the resistance of each heating element with an ohmmeter. A broken element will have infinite resistance. Replacing the heating element is a common and inexpensive repair.

Convector thermostat gets stuck

A bimetal thermostat (mechanical) or an electronic controller can fail so that the convector either continuously heats (thermostat remains in the "on" position – dangerous overheating) or does not turn on at all (remains in the "off" position). A bimetal thermostat is relatively cheap, but it depends on the availability of spare parts for the specific model. For more information on controlling ORAVA convectors, read the article Regulation and temperature setting for ORAVA convectors – how to properly control heating.

Discoloration or odor on first use

A new convector may emit an odor and slightly smoke when first turned on – this is normal. It is due to burning off protective oil or dust from production and transport. After 20–30 minutes of operation with an open window, it will stop. If the odor continues for a long time or is distinctly electrical (burned insulation), immediately turn off the convector and report it.

Convector does not respond to remote control or WiFi

Newer models with WiFi or IR control may have problems with pairing or signal range. The solution is usually to reset the device (unplug it for 30 seconds) and pair it again. If the router is far away or behind a thick wall, a WiFi extender may help.

When to call a service technician and when you can handle it yourself

Working with devices under 230 V or 400 V is regulated by law. Not every repair can be done by yourself – not only for legal reasons, but primarily for safety. Here is a general division:

DIY (without electrical qualification)	Requires an electrician or service technician
Bleeding radiators	Replacing a heating element
Adding water to the system	Replacing control electronics
Resetting the emergency thermostat (if you know the cause)	Replacing the pump (work with electrical installation)
Opening/closing valves, thermostatic heads	Insulation diagnosis, current measurement
Checking pressure with a pressure gauge	Replacing the safety valve (system must be depressurized)
Replacing a gasket (after depressurizing, without electrical work)	Hydraulic balancing of the system
Cleaning filters and threaded strainers	Electrical installation inspection, fuses

Prevention of faults – what to do to avoid recurring problems

From a long-term service perspective, prevention is cheaper than repair. Here are specific measures that realistically extend the life of the boiler and reduce the frequency of faults:

• Annual check before the heating season – check the pressure, bleed the system, and visually inspect the safety valve and connections. This takes an hour and saves you service technician visits.
• Water softening or corrosion inhibitors – in areas with hard water, an investment in a water softener is quickly amortized by energy savings and longer life of the heating element.
• Expansion tank pre-charge pressure check – check the pre-charge pressure every 2–3 years (when the system is cold, i.e., after draining the water part) and add nitrogen or air as needed to 0.5–0.7 bar.
• Filter cleaning – there is usually a magnetic filter or strainer behind the boiler or in front of the pump. Clean it once a year.
• Do not operate the boiler without water – if you plan to be away for a long time in winter, set a minimum frost protection temperature (typically 7–10 °C), not turn off the boiler completely.
• Overvoltage protection – overvoltage protection in the distribution board extends the life of the control electronics, which is vulnerable to lightning and power outages.

A comprehensive overview of maintenance tasks and their frequency can be found in the article Maintenance and service of the ORAVA electric boiler – what to check and how often.

Warranty claims and repairs outside warranty

ORAVA electric boilers are distributed with a standard legal warranty of 24 months for consumers. When claiming warranty, a few practical notes apply:

The warranty does not cover faults caused by incorrect installation, wear and tear (a heating element covered in limescale is often excluded from warranty, as it is considered damage caused by operation in unsuitable conditions), or mechanical damage. Therefore, it is important to keep the installation protocol from the electrician, or a proof of correct installation, in case of a dispute.

Outside warranty, spare parts for ORAVA boilers are generally available and affordable. A heating element typically costs 30–80 €, a circulation pump 60–150 €, a temperature sensor NTC 5–15 €. The control board is the most expensive item (50–200 € depending on the model), and in the case of older boilers, it may not be worth it – in such cases, it is reasonable to consider replacing the entire boiler. For selecting a new electric boiler, read the article How to choose an ORAVA electric boiler or convector – what to focus on.

Most frequently asked questions (FAQ)

The ORAVA boiler reports a fault, but it was working normally before – what could have happened?

The most common cause of a sudden fault without prior warning is a power outage or a voltage spike (a storm, switching on a powerful appliance). Try disconnecting the boiler from the power supply for 30–60 seconds and turning it on again – a so-called hard reset. If the fault persists, check the pressure in the system (manometer on the boiler) to see if it is too low or high. If everything is in order, contact the service with the specific fault code from the display.

The pressure in my ORAVA boiler keeps dropping – I have to refill it every few days. Is this normal?

No, this is not normal. In a tight system, the pressure should remain stable for months. A dropping pressure indicates a water leak – either visible (drops on the floor, a wet wall), or hidden (for example, the safety valve is dripping into a waste pipe that you cannot see). Check the safety valve and all connections. If you cannot find the cause, call a plumber with a pressure test – the system will be pressurized with air or nitrogen and the drop will be monitored.

Why does my ORAVA EK-2003 electric boiler consume more electricity than it did a year ago?

The most common cause of increased consumption without any obvious change in weather or ventilation is the accumulation of limescale on the heating element. Layers of scale act as thermal insulation – the element must be on longer to deliver the same amount of heat. Another possible cause is a deterioration in the building's thermal insulation (old windows, air leaks) or a worn circulation pump with reduced efficiency. Compare current consumption with last year's figures for the same period – if the difference exceeds 10–15 %, there is a problem that needs to be located.

Can I replace the heating element in my ORAVA boiler myself, without an electrician?

It depends on the design. The mechanical part of the replacement (draining, emptying the water, removing the element) is physically accessible to an average DIYer. However, connecting the new element to the electrical part (terminal block, protective conductor) should be done by an electrician, mainly for safety reasons and liability in case of fire or injury. Moreover, if you repair the boiler yourself and a fire occurs, your insurance may not cover the damage. A responsible repair = with an electrician.

My ORAVA VL-202 convector emits a burnt smell even after long operation – is this normal?

No. A smell during the first start-up (first 20–30 minutes) is normal – it is the burning off of dust from production. If the smell persists after further operations, it may be due to accumulated dust on the heating element (clean it with a soft brush when the appliance is turned off and cooled down), or – more seriously – a damaged insulation of the heating element or wires. In such a case, immediately turn off the convector, unplug it from the power supply, and contact service or the seller.

The boiler loses pressure only in summer, when it is not heating – why?

In summer, when the boiler is out of operation, an expansion tank with a damaged membrane can slowly release water through the membrane into the air chamber. The system thus loses volume and, when started in autumn, the pressure is low. Another possibility is that the seals are less compressed in summer (without pressure cycles) and slightly leak. Check the membrane of the expansion tank and the seals after the summer shutdown before starting the heating season.

Conclusion

ORAVA electric boilers and convectors are structurally relatively simple devices, and therefore their faults are mostly diagnosable and repairable – if you know where and what to look for. The key to long and reliable operation is a combination of correct installation (more about it in the article Installation of the ORAVA electric boiler O

Do you have a question on this topic?

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