Hot Water Air-Heaters for Horticulture

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Doll hot water-register air heaters of the type-series WDA (Warmwater-Doll-Automatic) have been approved for application in greenhouses of all kinds of constructions since decades. 

Due to the outmost solid and robust construction as well as the humidity- and UV-protected motor, Doll devices are also able to be  installed energy saving in vertical air direction below the greenhouse ceiling. Special Doll blow-out feedheads with adjustable air steering fins in all four directions are available for this kind of installation. 

The casings are serially made of fully zinc-coated steel platings (lacquering in RAL-colors on demand available for an extra charge).

The devices have been specifically developed for the increased requirements in the horticulture sector. The heat registers can be manufactured in copper aluminium (standard) or steel zinc-coated completion - as well  made of stainless-steel.

The devices are designed for high performance air-throughput and long durability, also under hindered conditions of usage in greenhouses, in which the air is additionally charged with dust and humidity. The core piece of the device is a high grade heat register in completions CuAl, steel zinc-coated or stainless-steel. The ventilator components are carried out as two-step special ventilators as external rotors from a market-leading German manufacturer. The motor of this type of construction is encapsulated and protected from humidity and dust and safely integrated in the ventilation rotor. Before assembly, the ventilators are balanced statically and dynamically for a smooth running at high performance air-throughput and for a long durability. By application of the comprehensive accessories programme these devices are capable being wall- or ceiling-mounted as well as for recirculating-, fresh- or mixed-air operation.

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  • wall- or ceiling mounting capable - rugged device-completion matching requirements in the horticulture sector.
  • operation with no exhaust line attached or ventilation engineering-measured compatible hot-air hose. 
  • high-grade heating register in copper-aluminium, steel zinc-coated or stainless-steel completion for all common supply temperatures.
  • in copper-aluminium heating-register completion serially-equipped with persistent aluminium fins and collector-tubes made of steel for improved cold resistance!
  • special external rotor axial-fan, motor protected from humidity and dust made of aluminium diecasting. 
  • high performance air-throughput at lowest acoustic emissions, in 2-step-switchable completion or if demanded 5-step-switchable completion.
  • air outlet-grids with adjustable air-steering fins / special blow-out versions available depending on conditions in the greenhouse and specific cultivations.
  • specific blow-out variants available depending on building conditions and utilisation of the air-heaters.
  • terminal box serially attached on the casing outside - ready to use.


Doll-WDA devices are German TÜV / GS audited and certified. The devices comply with the requirements of the EU machinery directive and are incorporating the CE-sign. Trust in our over 30-year expertise in the horticulture sector!

Industriegebiet Schlattwiesen | 72116 Mössingen | Tel: +49 (0)7473 - 77 11 | Fax:+49 (0)7473 - 23 778