UNIT HEATERS -WARM AIR INDUSTRIAL UNIT HEATERS

Unit Heaters – THE FH SERIES – LTHW / MTHW or HTHW

Heat outputs from 6.5 kW to 344 kW

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Industrial Unit Heaters – Hot Water – Low temperature hot water or medium temperature hot water – From Flexiheat UK

Unit Heaters -These Flexiheat Unit Heaters are normally supplied for LTHW (Low Temperature Hot Water Heater, or Medium Temperature Hot Water –  MTHW – up to 105 C) and are a water-supplied forced air unit heaters.These suspended warm air industrial unit heaters can discharge warm air either horizontally or vertically.These hot water fan heaters have a powerful axial fan which means it is suitable for many commercial and industrial heating applications. Flexiheat offers an extensive range of accessories allowing these hot water air heaters to be aligned to your site requirements.Our warm air unit heaters offer cost effective and energy efficient water heating solutions suitable for heating warehouses, heating workshops, heating factories and many more applications.

We now supply two ranges of these Industrial Unit Heaters , our Flexiheat range – detailed below and the Kroll range, we also do a steam unit heater range,which are detailed on it’s own web page –

Steam Unit Heaters from 14.6KW to 459KW Output If you require more information we have a dedicated web page here

Industrial Unit Heater Operating Principle

The heating hot water or steam from your boiler flows through a radiator heating coil, there an electric fan forces air through the radiator coil ( this is why these unit heaters are sometimes referred to as a forced air unit heater) ,the air passing over the heat exchanger absorbs the heat from the hot water or steam, that is feeding the heater,culminating in a higher discharge air temperature. The cooler water leaves the heat exchanger and is pumped back to the boiler to reheated, and the process starts again. Thus, often these heaters are referred to as forced air unit heaters or fan coil heaters,

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The two discharge options – downward or horizontal – meet all likely space configurations. Downward discharge is particularly suited to complex areas where obstacles might impede airflow’s from a horizontal unit. However the horizontal discharge units, with adjustable louvers, are ideal where directional heating (e.g along production lines) is required.These unit heaters are of compact construction and can be mounted easily anywhere.

The “FH” range of industrial unit heaters are designed for use in warehouses, distribution centres, showrooms, changing rooms, sports halls and car garages and are compatible with new and existing biomass heating systems, heat pumps heating systems or other traditional wet heating systems.

Benefits of a hot water unit heater in Industrial and Commercial Heating applications –

  • High reliability, as the only moving part is the fan assembly and motor -and if the motor fails, it is a very simple task to replace.
  • Clean heat with no odours, and no by-products of combustion to flue away or naked flame to worry about !
  • High Efficiency
  • Lightweight and compact for simple and easy installation
  • Large range of heater sizes to match the heater to your heating load required. When selected properly, you don’t have to worry about under or over sizing the heaters
  • The fan speed can be adjusted on all models which allows you to have the perfect airflow
  • Highly Durable. as all of our unit heater casings are treated for corrosion resistance and finished with a grey powered paint
  • Summer mode – The fans can run to the help circulate air in the summer period
  • Multiple unit heaters can be spaced strategically for zoning unique areas within the building, giving you maximum control and heating efficiency.
  • No oil or gas is required to be piped up to high level  as in the case of utilizing direct or indirect warm air heaters powered by those fuels

Unit Heater Technical Details

Firstly, we have the commercial unit heater range of these hot water fan heaters / hot water unit heaters. This range has an output range from 7.3 kW to 66.8 kW depending on the water flow and return temperature, and also the entering air temperature to these water to air space heaters. They have a water heat exchanger, which is sometimes referred to as a heating coil which is manufactured from copper tube, with aluminium fins attached.The maximum working temperature for this range of commercial unit heaters is 95°C,with a maximum working pressure of 16 Bar, on a wet heating system.

The following output data table is based on an entering air temperature of  15°C to the heaters , and a flow and return hot water temperature of 90/70°C.The cooling capacity, which is option on certain units is based on an entering air temperature of 25°C, with a flow and return temperature of the chilled water of  07/12°C.

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Then we move onto our industrial range of unit heaters. This range has an output from 7.3 kW to 117.7 kW, again depending on the water flow and return temperature, and also the entering air temperature to these water fed industrial air space heaters. Again this technical table is based on an entering air temperature of 15°C to the heaters , and a flow and return hot water temperature of 90/70°C, and when used in the cooling mode or operation, the data is based on entering air temperature of 25°C, with a flow and return temperature of the chilled water of 07/12°C.We also have this data based on different entering air temperatures, and different flow and return temperatures, such as 80/60 degrees C, 70/50 C and 60/40 C etc, which is vital data should you wish to use these unit heaters on low temperature heating systems, that are common in heat pump installations. Get in touch with us if you require this additional information.

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Download VEX Air Unit Heater Brochure

Download VEX Technical Manual

And for the larger output units –  that go from 19.4 kW to 117.7 kW in output

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Download the Flexiheat FH Industrial Unit Heater Range Brochure

You can see below, the left hand picture is of the standard fan coil heaters that work on a hot water heating system, and on the right is the fan coil unit heating and cooling. This water heater with cooling option,can only be installed on the wall – blowing air horizontal and can not be used in a vertical orientation ,as they come with a condensate drain pan. When the unit is cooling mode, the ambient humidity condenses on the coil. Thus, it is necessary to recover it by connecting a drain pan.

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The left picture is of our standard hot water fed unit heater and on the right is our unit heater that can be used for heating and cooling applications


Unit Heater Mounting Height Recommendation

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Industrial Unit Heaters – Installation Data

The FH warm air unit heaters offers cost effective and energy efficient water heating solutions suitable for heating warehouses, heating workshops, heating factories and many more applications.

The two discharge options – downward or horizontal – meet all likely space configurations. Downward discharge is particularly suited to complex areas where obstacles might impede airflow’s from a horizontal unit. However the horizontal discharge units, with adjustable louvers, are ideal where directional heating (e.g along production lines) is required.

Unit heaters can operate with low temperature hot water as standard, but we can also supply units that use medium or high temperature hot water, please see the FHTERM series of industrial heaters below on this webpage.

The integrated heat exchanger is made of copper/aluminium for hot water – low temperature hot water – as a heating medium. The units are splash water protected (protection class IP54).Operation with outside air, mixed air and recirculating air is also possible.

Normally used in a 100% recirculation warm air heating mode, in that the air in the area being heated is continually being drawn over the heater coil and expelled into the area. We also have the option to mount the air heaters with a mixer box, which enables fresh air to be added to the heater, resulting in a mixture of recirculated and fresh air being introduced into the heated area.

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Accesories for the VEX and FH range of Industrial Unit Heaters

When the mixer box is used in conjunction with either a motorised or manual damper, the air flow through these industrial unit heaters, can be set to either 100% recirculated air to 100% fresh air or anywhere in between these values.

The mixer box is usually connected to the external fresh air via a grill, which can be either wall mounted, which is the most common setup. Alternatively, you can also mount the grill in the ceiling or even below the heater. It is important to note , that when utilizing fresh air form outside the building, that these heaters either have a control system that has a frost protection system or that the heating system water is dosed with anti-freeze, to prevent the water freezing in the heaters coil or heat exchanger, when the units are not in use.

In the top left of the above picture is diagram showing one of our warm air unit heaters fitted with a G3 efficiency filter fitted, this is essential if the unit heaters are to be installed in a dusty environment, so that any build-up of dust on the heating coils is prevented, which would affect the correct operation and heat output of the units.

The multi-stage adjustable fans can be adapted to the requests on site. They assure draught-free, area-wide and comfortable distribution of heat and air. In order to calculate your requirements, our Flexiheat consultant team is at your disposal.

  • The large range of different models with multi-stage fan permits an optimal warm air heating or cooling solution to your requirements
  • Suitable for every room: they can easily be changed from wall-mounting to ceiling-mounting, which makes them extremely versatile
  • The low noise level ensures a silent operation and prevents noise pollution
  • With the right accessories, a comfortable room climate becomes the most natural thing
  • Ability to rotate the unit heaters through 180 ° – So the connections can be on the left or right

Rotating Unit Heater

Unit Heater Pipework Connection Kits – Optional Extra

Unit Heater Pipework Connection Kit

How do I calculate the heating load for my warehouse or commercial building?

ANSWERCall us as we are happy to run a heat loss calculation that will help you pick the perfect unit heater or heaters for your site conditions, as you do not want to under size, or over-size the heaters, PLEASE DO NOT FALL for unit heaters that are advertised as “will heat up to 1,200 square feet”. As heating a 1,200 square foot insulated warehouse in Kent, is an awful lot different to heating a 1,200 square foot un-insulated warehouse in Aberdeen. This one heater cannot “magically” service both 1,200 square foot spaces.


UNIT HEATERS – MTHW OR HTHW – WARM AIR UNIT HEATERS WATER FED

Heat outputs from 6.5 kW to 344 kW

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This range of industrial unit heaters, which are designated the “FHTERM WB Range” are fitted with a bi-metal water heating coil / heat exchanger and can be fed with a water temperature of 150 Degrees C or lower and with the operational pressure of up to 16 Bar. This makes these industrial warm air unit heaters suitable for installation on heating systems that use MTHW – (Medium Temperature Hot Water) heating systems, which in the UK, is normally defined as a heating system with a maximum flow water temperature of 120 Degrees Centigrade.

They are also suitable for HTHW – (High Temperature Hot Water) heating systems, which again in the UK are normally defined as a heating system with flow water temperature of above 120 Degrees C.

The FHTERM- WB range are a water-supplied suspended warm air industrial unit heaters which can discharge air horizontally or vertically. These industrial unit heaters benefit from powerful axial fans which means they are suitable for many industrial and commercial warm air heating applications.

The heat exchanger or coil of these “FHTERM WB Range” industrial warm air unit heater range is made from steel pipes with an internal diameter of 12.4 mm and spirally rolled aluminium ribbing with external diameter of 38 mm and with a rib spacing of 2.8 mm. These type of heat exchanger or coil is referred to as a bi-metal heating coil or heat exchanger. All of these commercial and industrial unit heaters are available with either a two row heating coil or a three row heating coil- the more heating coils , the larger the heat output available

If you intend to use these unit heaters hanging from or attached to the ceiling, then they can be equipped with either with a slot diffuser, which distributes the warm air out of the heater via a four-sided air distribution head assembly, which we refer to as a slot diffuser or they can be fitted with a cone discharge nozzle, which extends the warm air throw of these forced air unit heaters.

Using the slot diffuser- When the units are used in a ceiling mounted or hanging unit heater configuration the models FHTERM – 0 and 1 units can be hung at the maximum height of 4 metres, and the FHTERM 2, 3 and 4 units can be hung at the maximum height of 6 metres

The first two units in the range, which are the model 0 & 1 are supplied only with single phase motors, which are 230 Volt / 50 Hz / 1 Phase

The model 2 unit heater can be supplied either with a three phase motor, which is 400 Volt / 50 Hz or with a single phase motor which is 230 Volt / 50Hz.

The models 3 and 4 industrial unit heaters are supplied only with the three phase motors which is 400 Volt / 50 Hz.

The three phase motors of models 2,3, and 4 can be connected in Star or Delta wiring configuration depending on your site requirements.

The model “0” comes with an IP40 rated fan motor as standard and an insulation class of “B”, whilst the rest of the industrial unit heaters come with an IP54 rating and an insulation class of “F”. At request we can supply these industrial unit heaters with the motors with an increased level of anti-explosive protection, for warm air industrial heating applications that require this level of protection.

These Industrial unit heaters cannot be used in areas or locations with relative humidity above 95% and air dust concentration over 3mg/m3. And the model “0” should not be used in high humidity locations at all.

Industrial unit heaters are invariably the most cost-efficient method of space heating a room or building,with warm air.They are a perfect heater for an industrial unit.

Model “0” Industrial Unit Heater Heat Output Data – 1 Phase Only

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Model “1” Industrial Unit Heater Heat Output Data – 1 Phase Only

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Model “2” Industrial Unit Heater Heat Output Data – 1 Phase or 3 Phase Available

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Model “3” Industrial Unit Heater Heat Output Data – 3 Phase Only

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Model “4” Industrial Unit Heater Heat Output Data – 3 Phase Only

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Unit Heaters -These Flexiheat supplied Kroll Unit Heaters are normally supplied for LTHW (Low Temperature Hot Water) as standard, although we can supply them of MTHW or Steam if required)  and

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Industrial Hot Water Fed Unit Heaters available in Stainless Steel for corrosive atmospheres from Flexiheat UK

Units can also be supplied in stainless steel

The multi-stage adjustable fans can be adapted to the requirements on site. They assure draught-free, area-wide and comfortable distribution of heat and air. In order to calculate your requirements, our Flexiheat consultant team is at your disposal.

  • The large range of different models with multi-stage fan permits an optimal solution to your requirements
  • On request, also special versions such as explosion-proof units or units for operation in chicken / pig farms /stables are available
  • Suitable for every room: they can easily be changed from wall-mounting to ceiling-mounting, which makes them extremely versatile
  • The low noise level ensures quiet operation and prevents noise pollution
  • In addition to the standard powder-coated versions, all models are also available as a version with stainless steel casing
  • Ability to rotate the heaters through 180 ° – So the connections can be on the left or right, c/w air vents on both connecting nipples
  • With the right accessories, a comfortable room climate becomes the most natural thing

Download the Flexiheat “FHTERM” Unit Heater Brochure

Industrial Unit Heaters for Sale UK and Ireland 

So if you require a well made and high quality hydronic unit heater or water fed unit heater / forced air unit heater / hot water air heater our Industrial Unit Heaters are the perfect solution for your hot water warm air heating system and are particular suited to heating car garages and workshops , as well as any industrial unit or premises.They are often used in conjunction with biomass or air source heat pumps heating systems, as well as the traditional gas or oil fired heating systems.If you require any further assistance with our Industrial & Commercial Unit Heaters or any of our products, please click here to contact us via email or call us direct on 01202 822221