Suspended Direct Fired Natural/LPG Gas Warm Air Heaters

Outputs from 16kW to 100kW

These units are direct fired warm air heaters, which means that they add CO2 from the combustion process into the area. This makes them particularly suitable to greenhouse / poly tents heating, as the plants or crops use the CO2 beneficially, and are also very popular as a poultry shed heater / breeding shed heater.The FHG direct fired warm air heaters have been developed and certified in compliance with Msz EN 525:2001 standard and qualified for heating of industrial and agricultural spaces. The function of these heaters is to ensure the temporary or continuous heating of the designated work areas or agricultural spaces. In case of proper use, these warm air heaters guarantee safe and energy-saving operation. The combustion product is discharged in the space to be heated along with the hot air.Robust technology and extremely high manufacturing quality ensure flawless operation.

Characteristics of our Gas Fired Warm Air Heaters 

  • High efficiency (100%)
  • Low NOx and CO emissions
  • Stainless steel bodywork
  • Thermostatic control

High Efficiency Direct Fired Warm Air Heaters

The units have an  high efficiency of 100% and you can use a room thermostat to closely control the temperature thus saving energy.

Thanks to the thermal control, you can also use the heaters as frost guards. Using a thermostat, the heater is then automatically activated, to keep rooms free from frost or to avoid excessive drops in temperature. The short heat recovery time reduces temperature fluctuations, promoting a natural growing environment, and the fan provides circulation to reduce dead spots in the greenhouse, reducing high moisture areas that promote mold.

Direct Fired Warm Air Heaters – A Complete Range 

The power output goes from 30kW to 120 kW,with 8 Direct Fired Warm Air units within the range, The LH air heater is equipped with a temperature control unit located on the side of the control panel in the direction of the air fan. The control interval is 0-40C .The automatic control of temperature is carried out through the automatic switching
on and off of the appliance in accordance with the air temperature in the room and the set temperature value.

FHG36-16  –   16 kW output model

FHG45-45 –   44 kW output model

FHG56-75   –  75 kW output model

FHG56-100     100 kW output model

 Technical Data

Poultry Heating with Natural and LPG Gas

A reliable heat supply is essential to all businesses. But for poultry farmers it really can be a matter of life and death as birds thrive on consistent levels of heat – especially during the rearing season. The Flexiheat range of gas air heaters can offer a perfect solution in ensuring a constant , reliable and efficient heat source  for this application


  • Clean and efficient burning
  • Cost effective
  • Expensive oil spill fines can be avoided and the environment is kept unharmed
  • Rapid shed heating
  • Reliable and dependable fuel source


Every unit has got a built-in pressure controller.


The standard appliances provide three safety units-

Airflow sensor – Should the fan fail, the direct fired warm air heater would immediately stop
Ionization flame monitoring – The gas supply stops immediately as soon as the gas flame would go out.
Temperature limiter – the built-in protection thermostat prevents the unit from overheating.

The gas flame is constantly monitored by thermo elements and ionization electrode, making these warm air heaters a very safe warm air heater.

These Direct Fired Warm Air Heaters can be operated in three modes:


In this case, no heating is required in the room, but the fan is operated to ensure either air change or air circulation. Set the ON/OFF switch, which is the lower one on
the side of the control cabinet, to ON position. Set the upper “Heating-Ventilation” – “Heating” switch to “Heating-Ventilation” position. Set the thermostat to the minimum.
If set this way, the appliance will only ventilate the room.

The switches have to be set in the same way as it is done with the “ventilation only” mode, the only difference is that the thermostat has to be set to the desired temperature.
When the temperature in the room drops below the set value, heating is started.After the room’s temperature is increased to the value set on the thermostat, the appliance
will perform ventilation only.

Set the ON/OFF switch on the control cabinet to ON position. Set the upper two position switch to the “Heating” position. If set this way, the appliance heats up the
room to the temperature set on the thermostat, and when the desired value is reached, both heating and ventilation will stop.

Direct Fired Gas Warm Air Heaters – Safety Advice
  • If the heater is used in a closed space, adequate amount of ventilation air has to be supplied
  • The appliance should not be exposed to the following strong effects: wind, high pressure water jet, rain or dripping water
  • As dust is flammable, the appliance should not be used in rooms with high dust concentration.
  • Keep the appliance away from flammable materials such as fuels, solvents and combustible fluids.
  • These warm air heaters are equipped with a thermostat, therefore, the appliance can start operating at any time depending on the settings.
  • It is strictly PROHIBITED to use the heater in rooms that are used for sleeping or continuously occupation.

Download Direct Fired Air Heater Manual

If you require any further assistance with our Direct Fired Warm Air Heaters / Suspended Warm Air Heaters , please click here to contact us via email or call us direct on 01202 822221