RHI Compliant - The world's first long term financial support programme for renewable heat

Unical RHI

Unical are one of the largest manufacturers of biomass boilers in Europe. they have a proven pedigree and were responsible for inventing the first gasification boilers in the early seventies. Their boilers are built to a very standard using only boiler plate for the furnace chamber. The large range of log and pellet boilers are all MCS and RHI compliant. http://www.unicalboiler.com/company


FIREX The new range of wood fired boilers with reverse flame and suction fan.

Renewing the traditional Unical forty years old wood boiler line, FIREX further enriches the biomass boiler group, one of the renewable energy sources.

So, here is a fascinating product, with which Unical goes back to its memorable red colour, with new tone, as well as a new technology, underlining the strong connection with the great innovations of Unical history and the future oriented technical impulse.

Particularly attractive design, innovative technology solutions, are all elements that represent the “winning mix” to the international market in order to have an affordable approach to green technologies.

Great emphasis once again, is given to the customer: easy control and regulation, ample wood storage for long lasting activity and reduced daily loadings.

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• Total gasification, pyrolytic combustion, wood fired steel boiler with reversed flame, from 34 to 55 kW

• Reversed flame combustion

• High efficiency (for solid fuels), higher than 82%

• Combustion optimization and control through the primary and secondary air adjustment via a butterfly adjuster with built-in non return valve

• Wood gasification placed on the suction side

• Grate and fire bars in stainless steel AISI 316

• Tray in high resistance refractory steel

• Internal rear wall in refractory material to avoid the condensate formation

• Loading and wood store maintenance through a wide, front insulated door and the combustion chamber door, both with 180° rotation.

• Anti-smoke internal door with complete rotation, placed between the external loading door and the wood store.

• Frontal bypass above the upper door

• Insulated handle and knobs for door openings

• Wood store 8 mm thick

• Casing insulation with anti-tear, rock wool mattress (50 mm thick) with external aluminium foil

• Thermostatic panel board for the automatic control of the boiler fan and the different installation types, such as:

• Heating only

• Heating and D.H.W. production, via a storage tank with single or double coil, or tank-tank

• Anti-overheating safety heat exchanger, made of a steel coil, immersed directly in the highest part of the boiler water.





Technical Information




Hot water, carbon steel, thermal group- with nominal output of 27 kW and 40 kW – equipped with modulating pellet burner and pellet reservoir for automatic feeding.






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• Pellet reservoir capacity: 150 kg

• Autonomy of operation over 23 hours at nominal output, in continuous operation without turning off the burner.

• Carbon steel boiler body with combustion chamber partially covered with refractory, 3 smoke passes.

• Certified efficiency higher than 90.3%

• Class 3 according to EN 303-5

• Wide and deep combustion chamber in order to assure:

• Complete combustion of the air/pellet mixture

• Cleaning of the wet walls

• Intermediate refractory stones between furnace and second pass that determine the inversion of the smokes

• Wide arc in steel entirely wet, that constitutes the 3rd smoke pass and acts as real heat exchanger

• Safety heat exchanger

• Casing insulation with tear resistant mineral wool mattress, 60 mm thick.

Pellet burner Complete of:

• Fan

• Certified burner control

• Ignition and combustion assembly in thermal steel

• External cap in thermoforming

Output modulation step by step, in four levels for:

• Consumptions optimization and polluting emissions reduction

Panel board that assures all the normal functions (ignition, extinction, re-setting, etc.) and besides:

• Visualization of the information through display

• Weekly programming

• Output management in “D.H.W. mode” that allows the combination with D.H.W. storage tanks.

• Visualization, with message, of the pellet level

• Signalling of pellet reserve (20%) through capacitive sensor

• Switch off at 10% reserve; notice for the consumer, due to lack of the pellet.

Safety devices

• Sensor against “pellet clogging”

• Thermostat against burner overheating

• Signalling of correct operation state of the sensors

• Protection against momentary electrical blackout, through the intervention of the control software that activates a correct procedure of turning off of the burner

• Overheating protection of the boiler water through the activation of all the pumps and procedure of automatic turning off of the burner

• Visualization of the alarms through sliding message on the display

• C.H. expansion vessel,10 litres

• C.H. safety valve, set at 3 bar and automatic air vent.


• Recirculation pump kit

• Thermostatic valve and recirculation pump kit

• Remote control


Total gasification wood fired steel boiler

• Inverted flame combustion
• High efficiency (for solid fuel) over 84%
• Optimisation and combustion control by regulation of primary and secondary air
• Wood gasification fan in suction
• Integral anti-condensing system with modulating thermostatic valves (patented)
• Wood store and combustion chamber wide inspection doors to facilitate loading and maintenance
• Casing insulation with 60 mm thick glass wool mattress
• Panel board for automatic water temperature and fan control
• Safety exchanger to prevent over heating composed of steel coil immersed directly in the boiler