For more than 60 years products from our house ensure the right temperatures. Through path- breaking developments in the field of refrigeration and air- conditioning engineering we have gained worldwide recognition.

Our product range covers unit air coolers, fan coils and finned heat exchangers. We only produce at our company located in Gerlingen near Stuttgart.

Fan Coil Units
Air Coolers
Heat Exchangers

Options DHN

Heat exchangers

Our air coolers are designed for refrigeration applications. Our cooler work efficient in the Standard Condtions according to EN 328, with refrigerants like R404A, R507A or R134a.

If a cooler should be operated outside the limits specified in the catalogues or the selection software, it is possible to adjust the circuiting of the air unit coolers to ensure the operation of the unit.

For different refrigerants e.g. R410A, R407C etc. special heat exchangers are available on request.

Water/ brine heat exchangers

Water connectionUnit air coolers can be equipped with heat exchangers for water or brine operation. Compared to refrigerant heat exchangers the ones for water operation are equipped with threaded fittings, and have an optimised circuiting for water / brine operation. On request the heat exchangers can be prepared for bleeding/ draining.

The maximum allowable pressure for "water" heat exchangers is PS 16 bar.

Regulary used brines are e.g.

  • Ethylene glycol
  • Propylene glycol
  • Temper
  • Tyfoxit

The heat exchanger consists of wide tubes for a minimum of pressure loss, and optimised ciruiting to suit your application.


Due to frost formation on the fins, coolers have to be defrosted regualary to keep their performance. Frost can be removed in many ways.

MS heater rods

MS heater rods are one of the greatest benefits of Roller air unit coolers. These heaters are designed for different purposes around the air unit cooler.

Defrost of air unit coolers

MS heater rodsThese MS heater rods can be retro fitted into most of the Roller air unit coolers. They can be simply inserted into the coil. The rods are made of stainless steel and have a special vulcanisation for the appliance in cold rooms.

These type of defrost is designed to work at cooling chamber temperatures near the freezing point, to boost the natural defrost of the ambient and to achieve a complete deicing of the cooler.

We don't recommend the usage of MS heater rods for defrost in low temperature applications.

Air conditioning, dehumidification

HVAC heatersIn many Roller air coolers there are already holes to insert MS heater rods in the air outlet to reheat the air. As this is a very use oriented option we are not able to supply saftey installations in case of heat and current supply of these heaters.

A simple protection against touching of the hot surfaces can be supplied on demand.

Defrost safety thermostat

The defrost safety thermostat terminates the defrost in case of an failure of the defrost control. A wide range of Roller air unit coolers is already prepared for the installation of the defrost safety thermostat.

Defrost safety thermostatTechnical data:

Fixed break point,
disconnects +25 °C,
connects +3,5 °C
Contact load at 230 V, 50 Hz:
ohmic Imax 25 A,
inductive Imax 5 A,
Protection class IP 44.
Connection cable 2 cores, 75 cm long.

Protection against corrosion

If an air unit cooler is defective, corrosion is one of the most possible reasons. That is why in certain cases it makes sense to protect the air cooler from possible damage caused by corrosive environments.

Contents of corrosive environments are for example:

  • Acetic and other organic acids
  • Amines and ammonia compounds
  • Chlorine 
  • Salt
  • Cleaning agents

In corrosive environmets the heat exchanger should be cleaned more often than in neutral environments, depending on the corrosiveness a minium interall of an quarter year is suggested.

Type C

If the complete heat exchanger is varnished by 2 K laquer or powder- coated it's called protection against corrosion type C.

These type of corrosion protection is used at the Co2olers.

Type D

Protection against corrosion type DThe protection against corrosion type D is a combination of different anti corrosion actions, that lead to sja atisfying result.

First of all the copper tube is protected by a sacrificial anode.

Second the complete heat exchanger ist coated, due to that it is hardly possible for corrosive agents to attack the basic components of the heat exchanger.

The usage of additional material has a negative effect of the performance of the air cooler. When desinging your refrigeration plant, be sure to check the protection against corrosion box in the selection software.

Protection against corrosion type D isn't possible at Co2oler units.

Type E

It's possible to manufacture the complete heat exchanger of copper. This leads to an increse of capacity by about 8 %.

The heat exchanger is then well protected against influences of salt, which is the most common corrosion phenomen at aluminium.

These type of corrosion protection is only possible at fin spacings < 6 mm.

Type F

Fins can be made of prelaquered finstock. Compared to the complete varnished heat exchanger the capacity is a little bit higher, but due to cutting edges the Aluminium is not as good protected as in type C or D.

Type G

Protection against corrosion is a combination of tinned copper tubes, prelaquerd aluminium fins and a varnishing of the two end plates. It is only possible up to a fin spacing of 6 mm.