Electric boiler – installation components
Electric boiler – installation components
An electric boiler is installed without a chimney or gas connection. You need to add pipework, controls, system protection components and, if required, a DHW cylinder. Click a number to open the matching product.
A number in the diagram takes you to the matching item in the list below.
Step 2: boiler and system protection
Step 3: pipework, radiators and underfloor circuits
Step 4: temperature control
Step 5: hot water production
Accessories for an electric boiler
An electric boiler is a common choice for flats, low-energy houses and buildings without a gas connection, where building a chimney is not possible or not desirable. The set is intended for heating engineers and installation companies adding the hydraulics, controls and water heating to the customer's boiler. ATRIA Europe does not supply the electric boiler itself. The electrical connection of the boiler, including the circuit protection and the supply cable, may only be carried out by a qualified electrician.
Installation procedure
- Before installation, check with the electrician the power input of the boiler, the required number of phases, the circuit protection and the capacity of the supply point. With higher outputs, it may be necessary to increase the reserved capacity with the distribution network operator.
- Mount the boiler according to the manual so that both the electrical terminal block and the hydraulic connections remain accessible. An electric boiler does not need a chimney, but it does need service space.
- Fit ball valves on the flow and return, and a heating filter in the return.
- Depending on the boiler version, add a pump, an expansion vessel and a safety valve – some electric boilers have them built in, while others are only a heat source without hydraulic equipment.
- Ensure a minimum flow through the boiler. If all the thermostatic valves closed at once, the boiler could overheat or report a fault; a bypass valve helps, or at least one radiator without a thermostatic head in the reference room.
- Run the pipework to the radiators or to the underfloor heating manifold and make the joints with screw fittings designed for the type of pipe used.
- If the boiler will also heat water, connect an indirect cylinder via a diverter valve and a cylinder thermostat. A filter and the cylinder safety equipment belong on the cold water supply.
- The electrician connects the boiler, the room thermostat and, where applicable, switching according to the low tariff.
Choosing the right parts
Controls have an exceptional influence on energy consumption with an electric boiler. A programmable room thermostat lowers the temperature when nobody is at home and, with dual-tariff metering, allows you to concentrate heating in the low-tariff period.
The expansion vessel is sized according to the water volume in the system. If the boiler works with a buffer tank that stores heat from the low tariff, the water volume increases considerably, and with it the required size of the expansion vessel.
The safety valve must match the maximum operating pressure of the boiler. For boilers without their own safety equipment, it belongs as close as possible to the boiler outlet, with no shut-off valve between them.
A filter is particularly important with electric boilers: dirt and limescale settle directly on the heating elements and impair heat transfer. Therefore, fill the system with treated water.
The hot water cylinder should be chosen according to the number of occupants and the habits of the household. With an electric boiler, a larger store that can be reheated during the low-tariff period is worthwhile.
Most common installation mistakes
- Supply cable or circuit protection designed without a calculation, or without checking the reserved capacity.
- A system without a guaranteed minimum flow – the boiler then shuts down due to overheating.
- A missing filter, so the heating elements quickly become clogged with sludge.
- An undersized expansion vessel after a buffer tank has been connected.
- A room thermostat placed where it is affected by sunlight or another heat source.
Commissioning and maintenance
First flush, fill and bleed the system and check it for leaks. Only then may the electrician switch on the power – the boiler must not be started dry. When switching on for the first time, check the gradual switching of the power stages and the function of the thermostat. Once a year, check the filter, the water pressure and the expansion vessel pre-charge; have the electrician check the tightness of the power terminals, which can loosen due to thermal stress.
Frequently asked questions
Does an electric boiler need an expansion vessel?
Yes, like every sealed water-based heating system. Whether the vessel is part of the boiler or needs to be added can be found in the technical documentation of the specific boiler.
Can an electric boiler be combined with underfloor heating?
Yes. An electric boiler can work with a low water temperature, so it is usually very well matched to underfloor heating. Balance the circuits with the flow meters on the manifold.
Does an electric boiler also heat domestic hot water?
If the manufacturer allows it, it heats an indirect cylinder via a diverter valve. The alternative is a separate electric water heater.
Which thermostat is suitable for an electric boiler?
Most often a programmable thermostat with a switching contact. With wireless or internet control, check whether the receiver only connects to the boiler's control terminals or whether it would have to switch a higher current.
What to order for the customer's boiler
For the electric boiler, prepare expansion vessels and safety valves, controls from the Room thermostats and controls category and a cylinder from the buffer tanks and water heaters range. Registered partners can see wholesale prices after logging in. We dispatch goods from our warehouse in Žilina and ship them throughout the EU.