Three phase water heater options

Our three phase water heater range of instantaneous water heaters are the perfect solution for instantaneous water heating with a three phase electric supply. We also do a 3 phase water heater with stored hot water options for applications where an instantaneous water heater can’t handle a peak domestic hot water demand and thus an element of stored water is required.

Efficient hot water supply is crucial for commercial and industrial applications. Instantaneous water heating is the most energy-efficient way of producing hot water electrically. Three phase water heaters offer a reliable and efficient solution for domestic hot water supply.

Three phase power

An electrical system’s phase determines the distribution of a load. What’s the distinction between single-phase and three-phase power supplies? A single-phase power circuit features two wires carrying alternating current (AC).

Typically, there is one power wire, known as the phase wire, and one neutral wire, with current flowing between the two. Three-phase power is a three-wire alternating current power circuit in which each phase AC signal is 120 electrical degrees apart.

Businesses and factories typically use a three-phase power supply, while residential homes typically use a single-phase power supply.

One significant distinction between single-phase and three-phase power sources is that a three-phase power supply can handle larger loads and power ratings that are required for three phase hot water systems.

Instantaneous water heater: hot water on demand

3 phase instantaneous water heaters are a great option for lower hot water demands. We have a full range of instantaneous water heater products that benefit from bare wire water heating technology (heating elements) for maximum energy efficiency and accurate hot water outlet temperature from the appliance for multiple draw off points.

These units are sometimes referred to as three-phase tankless water heaters, 3 phase instant water heaters, or a 3 phase electric instantaneous water heater.

The two smallest instantaneous water heaters – can be set to various outputs i.e. our 9kW to 15kW water heater can be set to either 9,11,12, or 15 kW to suit you water heating requirements.

Power output of the tankless water heaters	9kW to 15kW Output power rating	17kW to 24kW Output power rating	27kW instantaneous water heater	36kw instantaneous water heater
Energy efficiency class	A	A	A	A
Heat capacity ( power output setting options)	9/11/12/15 kW	17/18/21/24 kW	27 kW	36 kW
Power supply – Voltage	400V 3N~	400V 3N~	400V 3N~	400V 3N~
Mains water supply pressure (Bar) min – maximum	1 to 10	1 to 10	1 to 10	1 to 6
Hot water flow rate at Δt=30 in litres per minute	4.3/5.2/5.8/7.2	8.1/8.7/10.1/11.6	13	17.3
Rated current (Amps)	3 x 13/15.9/17.3/21.7	3 x 24.6/26/30.3/34.6	3 x 39	3 x 52
Dimensions – W x D x H (in mm)	245 x 126 x 440	245 x 126 x 440	245 x 126 x 440	315 x 140 x 492

Please note that the maximum water temperature this 3 phase instantaneous water heater range can produce is 60 °C. If your require higher water temperatures, then you need to look at our storage water heater option.

We go into full depth on this dedicated webpage about our electric instantaneous water heaters, which are all 3 phase powered. Here – Electric instantaneous water heaters

Storage three-phase hot water systems

Sometimes you’re going to need a storage water heater rather than an instantaneous water heater, as your water heating requirements or peak load are just too large for an instantaneous water heater to be able to cope with.

We offer a comprehensive selection of 3-phase-powered storage water heaters in duplex stainless steel (which has the best corrosion resistance), ranging in capacity from 80 litres to 1,380 litres, compatible with various stainless steel immersion heaters up to 108 kW in power.These immersion heaters come with a temperature regualtion thermostat and saftey thermostat.

commercial electric water heaters; commercial electric hot water heater; industrial electric water heater; industrial electric hot water heater;

Commercial & Industrial electric water heaters from Flexiheat UK

We offer a glass-lined or 316 stainless steel 3 phase water heater with a storage tank capacity ranging from 80 to 6,000 litres, equipped with immersion heaters capable of producing up to 400 kW of heating power so you can supply multiple draw off points. This water heater range can produce water with a maximum temperature of 80 °C, which is more than our electric instantaneous water heater range, which is 60 °C.

We go into more depth on our 3 phase electrical powered storage water heater range here – 3 Phase storage water heater range

Contact us

Should you require further assistance or information on our three phase water heaters, then please contact our sales team on 01202 822221 or click here for our email contact form.

24kW Electric Boiler

Electric boiler 24kW Output options

A 24kW electric boiler is a highly efficient and cost-effective alternative to oil, solid fuel, natural gas, or LPG boiler systems and even electric storage heating.

They are the ideal alternative for properties without mains gas supply and residences with gas boiler limitations or gas boiler restrictions, such as listed buildings or being sited in a bedroom, etc. An electric boiler can be used for a radiator wet central heating system and is also suitable for hot water underfloor heating systems for medium or small properties.

You will require a three-phase electric supply to be able to run the boiler; they do not make a single phase electric boiler at 24 kW of boiler output.

Our range of electric boilers can also be coupled to an indirect hot water storage cylinder to provide domestic hot water for hot water outlets such as showers, bath taps, or sink taps.

Our 24kW electric system boiler option has all the components required for a sealed heating system, such as an expansion vessel and an ErP-compliant modulating pump.

These boilers are not suitable for open-vented systems.

An eco-friendly heating and hot water solution

When you produce (such as a photovoltaic system, i.e., solar panels) or buy renewable electricity or “green” electricity from renewable sources to run your electric boiler, your electric heating system is carbon neutral and not impacting the environment.

When operating electric boilers, they emit no combustion gases or noxious fumes, unlike traditional gas boilers or oil boilers, as there’s no flue requirement with an electric boiler.

Electric boilers, with easier installation, are a very cost-effective alternative to existing tank-based fuels such as oil or LPG boilers and heat pumps. Air source heat pumps are expensive, and ground source heat pumps even more so, as the installation costs are extreme, to say the least, especially when compared to electric boiler installation costs, even when an upgrade to a three phase electric power supply is required.

Benefits

Compact units compared to typical oil, solid fuel, or gas system boilers
No mains gas supply to run to the boiler, only electrical cables.
No bulky external tank that you require when heating with oil or LPG systems.
Operates quietly—virtually silent
No chimney or venting system is needed, making them a perfect solution for listed buildings or medium to small properties that may have gas boiler restrictions.
No danger of carbon monoxide poisoning; there is zero risk.
Superior inner design that includes a built-in pump for sufficient flow rates for radiators or underfloor heating circuit and an expansion vessel for the heating system
Suitable for wet central heating, either radiator or underfloor heating systems
Can produce domestic hot water via an indirect hot water cylinder for sufficient flow rates to serve your hot water outlets.
Easy-to-use touch screen control panel interface for superior performance
Can be used with renewable electricity from renewable sources such as photovoltaic system, wind or water generated electricity etc.
Operating temperatures up to 80 °C
Running costs are reduced due to the high modulation of the heating system.
Electric boilers are a very cost-effective alternative to heat pumps, gas and oil boilers, or electric storage heating.
When operating electric boilers emit no harmful gases, fumes, or pollutants.
Warranty – 2 years
Only suitable for properties with three phase electrical supplies

24kW Electric Combi Boiler

We also offer a 24kW electric combi boiler, a boiler capable of providing space heating and instantaneous domestic hot water. You can find this electric combi boiler range from Flexiheat UK on its dedicated webpage – electric combi boiler range from Flexiheat UK. Please note that you will require a three-phase electric power supply to run an effective electric combi boiler. Our 24kW electric combi boiler will produce an instantaneous domestic hot water flow rate of 12.8 litres per minute with a temperature rise of 30 °C (the DHW temperature outputs range are adjustable from 30 °C to 55 °C). This flow rate is sufficient to fill a bath tub in a suitable timescale. They do not make a 24kw electric combi boiler in single phase.

Electric combi boilers really require a 3 phase power supply to produce an adequate domestic hot water flow rate. It’s as simple as that.

24 kW Electric boiler outputs options

The first question is why a 24kW boiler? Well traditionally the smallest gas boilers were 24kW in output and many people assume that this is the smallest boiler available in electric. This is not true, as they go all the way from the smallest output of 0.5 kW all the way up to 45kW for our domestic size electric heating boilers.

So, if you’re replacing a gas or oil boiler that’s 24kW – then the first thing you should do is check that this boiler isn’t oversized for your location – please see this webpage for guidance – What size electric boiler do I need?

We have a couple of options for around 24kW of output – these are

Our Model FHEL23, which is a fully modulating boiler – this unit has a maximum output of 22.5 kW – and will ramp up and down the following outputs to suit the heating demand of the system. Modulation range / power steps = 2.5,5,7.5,10,12.5,15,17.5,20 or 22.5kW

24kw output electric boiler option A from Flexiheat UK

FHEL23 boiler, with low heat output modulation – Output can be set to either – 2.5,5,7.5,10,12.5,15,17.5,20 or 22.5kW

The second option is our FHEL30 unit – this unit’s maximum heating power is 30kW – however this unit can be set to a maximum of 25kW output, so ever slightly over the 24kW, and the unit will ramp up and down this scale to suit the heating demand.

Output can be set to either 5,7.5,10,15,17.5,20,25,27.5 or 30kW

FHEL30 option for an electric boiler output of 25kW:electric boiler specialists installation

Please note – a heating expansion vessel need to be fitted external to the unit for this size boiler to make it a system boiler

The Amps required to power the unit at 25kW output is calculated as follows –

For Three Phase /415 Volt / 50 Hertz AC Circuit, that we use in the UK, then the calculation is –

Amps = (kW × 1,000) ÷ (√3 × volts)

Amps = (25 × 1,000) ÷ (1.73 × 415)

Amps = 25000 ÷ 717.95

Amps = 34.82 Per Phase – on the three phases of the electricity supply

Plus, you want to and the pump electricity requirements of one Amp per phase (3 Amps in total)

Thus, the maximum total electrical consumption would be 35.82 ( call it 36 Amps) per phase

The full brochure on these units is here –

Flexiheat Brochure For Electric Boilers

and the installation and technical manual is here –

Flexiheat Electric Central Heating Boilers – Installation & User Manual – FHEL Boilers

Domestic hot water production

Heating hot water for sanitary use – by using the heating electric boiler in conjunction with an indirect domestic hot water tank, you can supply plentiful amounts of domestic hot water for your bathing needs, be it showering, filling a bath, or washing up in the kitchen.

This hot water system ensures that the electric boiler does both your heating system and domestic hot water—the wet central electric heating system, be it radiators, underfloor heating, or a mixture of both and the domestic hot water via indirect cylinders. We refer to electric boilers in these circumstances as system boilers.

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A diagram showing how an electric central heating boiler is connected to a Domestic Hot Water Cylinder or Hot Water Tank

Control options

Using an appropriate controller on our electric boilers can produce superior performance and lower monthly running costs.

OpenTherm is a communication protocol between heating controls and the boiler to modulate the temperature flow through a heating system.

Since it’s a standard protocol, any “OpenTherm” controller, such as Nest, Hive, Honeywell, Drayton, etc., can work with our electric boilers. There are so many manufacturers now that if the controller says “OpenTherm,” it will work and help reduce running cost.