Maintenance and service of the ORAVA electric boiler – what and how often to check

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Why it is worth regularly checking the ORAVA electric boiler

An electric boiler is technically the simplest of all types of heating appliances – it has no combustion chamber, no flue condensation occurs, and no chimney is required. Despite this, anyone who uses it for a longer period is very well aware that "simple" does not mean "maintenance-free". On the contrary: since an electric boiler operates in a closed heating circuit with water, the pressure changes regularly, the water ages, deposits gradually build up, and electrical components age. Neglecting regular checks manifests itself gradually – first with slightly higher energy consumption, then occasional outages, and finally a failure that cannot be resolved without emergency heating replacement during the minus temperatures of February.

In practice, I encounter two extremes. The first is an owner who installs the boiler, sets the thermostat, and does not return to it for the next three years – until a failure occurs. The second extreme is a customer who calls a service technician every month for every minor issue. The truth lies somewhere in the middle: there are several tasks that an average adult without professional training can easily handle, and several others that require an electrician or heating technician. This article will help you distinguish what belongs where, and most importantly – it will stop you from falling into the first category of completely passive users.

If you are also interested in choosing the right model, read our article How to choose an ORAVA electric boiler or convector – what to focus on, or What power of ORAVA electric boiler do I need for my household. Here we focus exclusively on operation and maintenance after installation.

Basic overview of components of the ORAVA electric boiler

In order to talk about inspections, we first need to know what the ORAVA electric boiler contains and where the critical points are in terms of failure risk and wear.

The main components that require regular inspection or maintenance are as follows:

Heating element (resistive spiral) – converts electrical energy into heat, sensitive to limescale and poor quality medium
Circulation pump – circulates water in the circuit, prone to clogging, cavitation and long-term shutdown
Expansion tank – compensates for thermal expansion of water, gradually loses pressure in the air chamber
Manometer and pressure sensor – indicator of the system's condition, malfunction may cause unnecessary boiler failure
Safety valve – safety component, when neglected it may "stick" in an open or closed position
Drain valves – on the boiler and radiators, air in the system significantly reduces efficiency
Control electronics and thermostat – correct calibration and function of temperature sensors
Electrical connection, circuit breakers, RCD – safety aspect of the entire installation

Frequency of inspection tasks – a clear schedule

One of the most frequent questions I receive from customers after boiler installation is: "How often do I actually need to do something?" The following table provides a clear answer. Tasks are divided according to who can perform them – an average user (U) or a professional technician (T).

Task	Frequency	Who
Check system pressure (manometer)	1× weekly during the season	U
Bleed radiators	1× before the season (September)	U
Visual inspection of the boiler and surroundings (leaks, drips)	1× monthly	U
Check the safety valve	1× annually before the season	U / T
Water top-up / pressure adjustment	As needed	U
Check expansion tank (membrane pressure)	1× annually	T
Flushing / corrosion inhibitor	Every 2–3 years	T
Check heating elements (resistance, limescale)	Every 3–5 years	T
Electrical installation inspection of the boiler	Every 3 years (legal requirement)	T (licensed electrician)
Check and if necessary replace the circulation pump	Depending on condition, at least every 5–8 years	T

Pressure control in the system – the most important daily task

This is a task that anyone can do, and it is the most important of all. The correct pressure in a closed heating circuit is the basic condition for safe and efficient operation.

The standard operating pressure when the boiler is cold (water temperature below 40 °C) should be in the range of 1.0 – 1.5 bar. When the system is fully heated (70–80 °C), the pressure naturally increases to 1.5 – 2.5 bar – this is normal and correct. Every ORAVA boiler has a manometer on the front panel that displays these values.

If you see a pressure below 0.8 bar when the boiler is cold, the system is losing water. The causes can be two: a leak somewhere along the line (leaky connection, safety valve, radiator connections) or a worn membrane in the expansion tank. The first thing you do is inspect all visible connections and the bottom part of the boiler – you are looking for water spots, drops or brown (oxidized) traces of dried water.

If, on the other hand, the pressure is consistently above 3 bar in a cold system, the expansion tank is not working properly or the system is overfilled. In such a case, the safety valve may open and release water – this is not a fault, it is a safety function, but it indicates a problem that needs to be addressed.

In practice, I often encounter the situation where the customer tops up the water, the pressure is corrected, and after a month it is low again. After the third topping up, this should make you look for the cause, not just keep topping up. A system that does not leak should not lose water at all – it is sealed.

Draining air from radiators and boiler – when and how

Air in the system is a silent enemy. You don't see it, the boiler works normally, but some radiators are only slightly warm, the system is noisy (gurgling, grumbling in the pipes), and the boiler runs longer to reach the set temperature. Result: higher electricity consumption with lower comfort.

Draining air is a simple task. Each radiator has an air vent – usually in the top corner. To open it, a key is sufficient (square flat screw or a special key for draining). Procedure:

Let the boiler run until it reaches full operating temperature, then turn off the pump or stop the boiler.
Prepare a cloth or a small glass.
Open the valve slowly – listen for the hissing of air.
When the hissing stops and water starts to flow (even slightly discolored), close the valve.
Check the pressure in the system – draining air will reduce it by 0.1–0.3 bar, possibly requiring topping up with water.

Some models, for example the ORAVA EK-2003, have an automatic air vent directly on the boiler. This also deserves regular inspection – whether it is leaking or the cover is clogged with limescale.

Significant air formation (you have to drain air every 2–3 weeks) indicates corrosion in the system or overly aggressive water. In such a case, it is time for a chemical analysis and possibly adding a corrosion inhibitor.

Pressure relief valve – regular inspection that people neglect

The pressure relief valve is a simple mechanical part that opens and releases water when the pressure is too high – thus protecting the boiler from deformation or bursting. The problem is that if the pressure relief valve has been working for years without opening, limescale deposits can literally block it – and then it won't work even in real overpressure. Or the opposite: the valve remains slightly open and slowly leaks, which causes a drop in system pressure.

Once a year before the heating season, you should manually test the pressure relief valve: on most valves there is a ring or lever that you open for a second – water flows into the waste hose. If it is too stiff to open, or if it continues to leak after closing, the valve needs to be replaced. It is a cheap spare part that a technician can replace in a few minutes.

Warning: the pressure relief valve must not be blinded, the waste hose must be freely connected (not into a closed space), so that water can flow normally when opened. This is a safety regulation, not just a recommendation.

Expansion tank – the heart of pressure management

The expansion tank is a pressure tank with a rubber membrane. On one side of the membrane is air (nitrogen) pre-charged to a value corresponding to the static pressure of the system (usually 0.75–1.0 bar), on the other side is the heating water. When the water heats up and expands, it compresses the air – the pressure slightly increases, but remains within a safe range. Without an expansion tank, every heating cycle would trigger the pressure relief valve.

The membrane in the expansion tank has a lifespan of 8–15 years, but the pre-pressure of air can be lost much earlier. If the pre-pressure is zero (membrane flat), the tank does not perform its function: the system quickly builds up excessive pressure when heated and the pressure relief valve opens. After cooling, the pressure is again too low.

The inspection is simple: turn off the boiler, release the pressure from the system, and attach a manometer to the air valve of the tank (similar to a bicycle tire). The value should be 0.75–1.0 bar for most home systems. If it is zero, inflate with nitrogen or dry air from a compressor. If it cannot hold pressure (drops quickly after inflation), the membrane is torn and the tank needs to be replaced.

Heating element and scale – a quiet long-term problem

The electric heating element (spiral, cartridge) is the core of every electric boiler. Its task is to transfer heat to the water. Scale that settles on the surface of the element has very low thermal conductivity – a layer of just 1 mm increases energy consumption by 7–10 %, and a layer of 3 mm can increase it by up to 25 %. These are not negligible numbers.

The rate of deposition depends primarily on water hardness. In many regions of Slovakia, hard water is common – a hardness above 30 °dH is quite common in unsoftened tap water. In such cases, I recommend addressing the issue preventively:

Use softened or demineralized water for the heating system
Add a corrosion and scale inhibitor to the system (e.g., Fernox F1 or similar)
Have a technician clean or inspect the heating element every 3–5 years

Visual inspection of the element is not possible without disassembly. An indicator of the problem is disproportionately high electricity consumption at the same outdoor temperature and the same settings. If you keep records of your consumption (which I recommend for every owner of an electric boiler), a significant increase in consumption without another reason indicates a clogged element.

For example, the model ORAVA EK-2004 has a replaceable heating element – the service can remove it, chemically remove deposits with acid, or replace it with a new one. This is much cheaper than replacing the entire boiler.

Circulation pump – how to tell something is wrong

The circulation pump ensures water circulation between the boiler and radiators. When it works properly, it is quiet or emits only a faint monotonous hum. Signs of problems with the pump:

Noise – squeaking, gurgling, or strong vibrations indicate cavitation (air in the pump) or worn bearings
Radiators do not heat evenly – the boiler reaches the set temperature, but distant rooms are cold while nearby ones are hot – the pump is not providing sufficient flow
The boiler overheats and shuts off on the safety thermostat – may indicate no or minimal flow due to a seized pump
The pump can be heard, but water is not flowing – most commonly after the first start-up in summer, when the rotor is blocked by rust. Solution: turn off, and gently turn the rotor by hand using the access screw on the front of the pump.

The lifespan of a quality circulation pump is 10–15 years with proper operation. When replacement becomes necessary, I recommend investing a bit in an energy-saving EC pump (class A) – the difference in consumption compared to an old class D–E pump can be 40–70 W of continuous savings, which amounts to 100–200 kWh per year.

Electrical side – what belongs to the electrician's inspection

An electric boiler is legally an electrical device of class I – it must have a valid inspection certificate. In residential buildings, electrical inspection is required every 5 years (Act No. 124/2006 Coll. and Government Regulation No. 508/2009 Coll.), but in the case of an electric boiler as an industrially stressed device, I recommend inspection every 3 years.

The inspection technician checks the following at the boiler:

Proper dimensioning of the supply cable and fuses (a 6–12 kW boiler requires a separate circuit, usually 3× 16 A or 3× 25 A)
Function of the residual current device (RCD) – the leakage current must not exceed 30 mA for domestic installations
Condition of the earthing (protective conductor PE)
Measurement of insulation resistance of the heating elements – this detects faults in the elements before they manifest as external failures
Condition of terminal blocks and connections – loose connections cause local overheating and are the most common cause of fires in electrical appliances

If you have recently moved into an apartment or house with an older ORAVA electric boiler and you do not know when the last inspection was, schedule it as soon as possible. I have indeed seen cases where the installation had been working for several years, but during the inspection, critical defects were revealed – cracked insulation, loose terminals, an uncalibrated RCD.

Water quality in the system – a long-term underestimated factor

A heating system is not a water supply. The water circulating in it should have specific chemical properties – pH 7.5–9.0, low hardness, and minimal oxygen concentration. Regular tap water does not meet these requirements in the long term: it contains dissolved oxygen (which promotes corrosion), has hardness corresponding to the local source, and its pH may be slightly acidic.

Therefore, every closed loop should have chemical protection:

Corrosion inhibitor – slows down corrosion of metal components (steel radiators, cast iron elements, copper in pipes)
Anti-corrosion preparation with scale protection – a combined product for hard water
Antifreeze mixture (glycol-based) – only for seasonally operated cottages, unheated buildings; note – it reduces the thermal capacity of water and requires a different pump pressure

Every 2–3 years, it is advisable to take a water sample from the system and have it analyzed. Some service companies do this for free as part of regular maintenance. If the water has become too dark (dark, cloudy), it usually indicates intense corrosion – the system needs a chemical flush and refilling with new water containing an inhibitor.

ORAVA Convector Heaters – Do They Require Different Maintenance Than Boilers?

Electric convector heaters, such as the ORAVA VL-202 or ORAVA VL-201, do not have heating water, a pump, or an expansion tank – their maintenance is therefore significantly simpler. Despite this, there are tasks that are easily neglected:

Cleaning of louvers and intake grilles – dust, hair, and dirt on the intake grille reduce air flow. The convector can overheat and the safety thermostat will shut it off. Clean as needed, at least once a year with a vacuum cleaner using a soft attachment.
Thermostat setting check – electronic thermostats (on models with LCD) may have a calibration drift. If you feel that the room temperature does not match the set value, compare it with a calibrated thermometer.
Check of the power supply and plug – for convector heaters with a fixed power supply: have an electrician check the connections in the distribution box every 3–5 years.
Wall mounting check – on wall-mounted models, the wall may shift over time or the anchoring screws may loosen. Also see our article Mounting the ORAVA convector heater on the wall – instructions and common installation mistakes.

For more information on the differences between a boiler and a convector heater in terms of operation, see the article Electric boiler vs. ORAVA convector heater – which heating type is more cost-effective.

Seasonal boiler preparation for winter – complete procedure

The ideal time for an annual service is September – before the first night frosts and when you will really need the boiler. Here is a procedure I recommend going through systematically:

Visual inspection – check all visible pipes, connections, and valves. Look for: water droplets, white lime deposits (traces of dried water), rust stains.
Pressure check – in a cold system, it should be 1.0–1.5 bar. If necessary, add water via the filling valve.
Pressure relief valve test – manually open for 2–3 seconds and check if it closes tightly.
Radiator bleeding – proceed from the highest to the lowest, and after bleeding, check the pressure.
Circulation pump activation – if the boiler has been idle all summer, try to manually unlock the rotor.
Boiler start-up and monitoring for the first 30 minutes – monitor the pressure during heating, listen for unusual sounds, and check for even heat distribution to the radiators.
Thermostat setting and test – verify that the boiler correctly turns off and on again when the set temperature is reached.

Seasonal boiler preparation for summer – shutdown

When the heating season ends (April–May), many customers simply turn off the boiler and forget about it until September. This is largely correct – but a few things are worth mentioning:

Do not drain the system unless it is absolutely necessary (e.g., renovation). An empty system corrodes faster than a filled one.
Keep the boiler on at least the minimum anti-frost mode (if available), or set the thermostat to 5–8 °C – protection against possible late frost in May.
Run the circulation pump at least once a month during the summer – 10–15 minutes is enough to prevent it from seizing.
Check whether water is leaking from the system (pressure should remain stable during the summer).

Maintenance records – why keep them

Keeping a simple maintenance record of the boiler may seem unnecessary to a customer at first – after all, it is just a home boiler, not a factory. But from experience, I know that these records help:

Quickly detect a pressure drop trend (three refills in a month = problem)
Prove regular maintenance when claiming warranty
When selling real estate, reliably present the boiler's history to the buyer
Give context to the technician during service

A simple notebook or Excel file is sufficient: date, task, pressure value, note. It doesn't have to take more than 2 minutes a month.

Warranty and post-warranty service – what the warranty covers and what it doesn't

The warranty for ORAVA electric boilers applies to manufacturing defects in the equipment – not to faults caused by unsuitable water, incorrect installation, operation outside the manufacturer's parameters, or mechanical damage. Therefore:

Have the installation done by a qualified person (electrician + heating installer) – you will then have proof of correct installation; see the article Installation of the ORAVA electric boiler – procedure, requirements, and what the electrician must do for more details
Keep the purchase receipt and warranty card
Have any service replacement documented
Do not exceed the maximum working pressure (usually 3 bar) or the maximum temperature set by the manufacturer

In the post-warranty period, the most common service items are: replacement of the heating element (after 8–12 years with hard water), replacement of the expansion tank (after 10–15 years), and replacement of the circulation pump. If the boiler is approaching 15+ years of age and requires several of these replacements at once, it may be economically worthwhile to consider replacing it with a new one – especially if it is an older model without electronic regulation and without the possibility of connecting to a smart thermostat.

Most common maintenance mistakes with ORAVA electric boilers

To conclude the practical part – mistakes I see repeatedly:

Ignoring pressure drop – the customer refills water month after month without looking for the cause
Draining the system every summer – unnecessary and speeds up corrosion
Using fresh hard water after every refill – each refill brings new limescale; use softened water after major repairs
Forgetting about the expansion tank – a component that works quietly for years until it fails
Mechanically securing the pressure relief valve – some people "lock" it with a rubber band or tape because it leaks. This is dangerous and illegal.
Never turning on the pump during summer – seizing and rotor blockage
Inspection by an amateur – electrical inspection must be performed by a certified technician; self-written records have no legal value

Frequently asked questions (FAQ)

How often should I refill water into the ORAVA electric boiler?

A properly functioning closed system should not require water refilling at all or only minimally (once a year after bleeding). If you need to refill water every 2–4 weeks, it means the system is losing pressure somewhere – look for a leak, check the pressure relief valve and the expansion tank. Every regular refill brings new minerals and oxygen into the system, which accelerates corrosion and limescale formation.

Can I service the ORAVA boiler myself, or do I need a professional?

Certain tasks can be handled by an average user: checking the pressure on the manometer, refilling water, bleeding radiators, and cleaning the filter (if installed). For checking the expansion tank, replacing the pressure relief valve, servicing the pump, replacing the heating element, and electrical inspection, you need a professional. Electrical inspection must be performed by a certified electrician – this is not just a recommendation, but a legal obligation.

Why does my ORAVA boiler occasionally make gurgling or rumbling sounds?

Gurgling usually indicates air in the system. Air tends to accumulate in the highest parts of the circuit – that is, in the upper parts of the radiators. The solution is to bleed all radiators in the system, starting with those on the top floor. After bleeding, check and adjust the pressure if necessary. If gurgling persists after bleeding, it may be due to intense corrosion producing gases – in such a case, a chemical water analysis and system flushing are appropriate.

What happens if I forget the annual service of the expansion tank?

If the expansion tank loses the pre-charge in the chamber section, it will no longer perform its function. When heating the system, the pressure will rise uncontrollably, the safety valve will open regularly and release water. This makes the system so-called "open" – water is refilled, bringing new oxygen and minerals, which leads to rapid corrosion and limescale formation. Long-term neglect will shorten the lifespan of the boiler and the entire system by several years.

Do I need to shut down the ORAVA electric boiler in summer or can it run all year round?

It is not necessary to mechanically shut down or drain the boiler in summer. Ideally, leave it running in the minimum anti-freeze mode (5–8 °C) – this protects the system from air and corrosion. The circulation pump should be run for at least 15 minutes once a month to prevent it from seizing. If you still want to completely turn off the boiler for the summer, the system will remain filled with water – this is fine, just don't forget to bleed the air and check the pressure when restarting.

Does the water hardness in my region affect the boiler's lifespan?

Yes, and significantly. In areas with water hardness above 20–25 °dH (German degrees of hardness), limescale accumulates on the heating elements much faster. We recommend filling the system with softened or demineralized water in such regions and adding an inhibitor for limescale and corrosion (e.g., Fernox, Sentinel or a similar product). You can find out the water hardness in your area on the water utility's website, or you can have the water tested in a laboratory – it is a cheap and very useful piece of information.

Conclusion – regular maintenance

Do you have a question on this topic?

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