Not registered yet? Take advantages of registration:
Products saving in a binding to the projects
Online consultation from experts

Privacy policy

Blauberg KOMFORT EC DBW 900-E L S21

Suspended heat recovery air handling unit.
Maximum air flow up to 1030 m³/h.
EAN codeEAN4058448073366
  • Description
  • Characteristics
  • Capacity diagram
  • Downloads
  • Designation key
  • Accessories
  • Dimensions
  • Additional characteristics

Air handling units for efficient supply and exhaust ventilation in flats, houses, cottages and other buildings. Heat recovery minimises ventilation heat losses. Provide controllable air exchange to create the best suitable indoor microclimate. Compatible with round Ø 200, 250, 315, 400 mm round air ducts.


The casing is made of double-skinned aluzinc panels, internally filled with 20 mm mineral wool layer for heat and sound insulation. The casing has fixing brackets with vibration absorbing connectors for easy installation. The spigots for connection to the air ducts are located at the side of the unit and are rubber sealed for airtight connection to the air ducts. The service panel ensures easy access to the internals for cleaning, filter replacement and other maintenance operations.



High-efficient external rotor EC motors and centrifugal impellers with backward curved blades are used for air supply and exhaust. EC motors have the best power consumption to air flow ratio and meet the latest demands concerning energy saving and high-efficient ventilation. EC motors are featured with high performance, low noise level and totally controllable speed range. Dynamically balanced impellers.

KOMFORT EC DBW... 550/900

The KOMFORT EC DBW...-E 550/900 unit is equipped with an enthalpy plate counter-flow heat exchanger for energy (heat and humidity) recovery. Due to humidity recovery condensate is not generated in the enthalpy heat exchanger.

The air flows are completely separated in the heat exchanger. Thus smells and contaminants are not transferred from the extract air to the supply air. Heat recovery is based on heat and/or humidity transfer through the heat exchanger plates. In the cold season supply air is heated in the heat exchanger by transferring the heat energy of warm and humid extract air to the cold fresh air. Heat recovery minimizes ventilation heat losses and heating costs respectively. In the warm season the heat exchanger performs reverse and intake air is cooled in the heat exchanger by the cool extract air. That reduces operation load on air conditioners and saves electricity.


The unit is equipped with a water (glycol) heater for operation at low outside air temperature. The integrated water heater is activated to warm up supply air flow if set indoor air temperature may not be reached by means of heat recovery only. Heat medium temperature control ensures supply air temperature maintaining. The air temperature sensor downstream of the waterheating coils and the return water temperature sensor are used for freezing protection of the water heater.


The units are equipped with a bypass for summer ventilation (room cooling by cool air from outside) and heat exchanger freeze protection.


The built-in G4 supply filter and G4 extract filter provide air filtration. The F7 supply filter (specially ordered accessory) may be used for efficient supply air filtration.


Mounting to the ceiling with fixing brackets. The correct mounted unit must provide free condensate collection and drainage as well as good access for servicing and filter replacement. Access for servicing and cleaning the filter: from the right or left side panel, depending on the unit modification.


The units are equipped with an S21 integrated automation system. The remote control panel is not included in the delivery set (available separately). The S21 controller allows integrating the unit into the Smart Home system or BMS (Building Management System). The unit can be controlled by the Blauberg AHU mobile application via Wi-Fi.

the Blauberg AHU
app for Android

the Blauberg AHU
app for iOS

Functions Description
Unit control via Wi-Fi using a mobile application +
Unit control via a wired remote control panel
S22 control panel (option)
Unit control via a wireless remote control panel
S22 Wi-Fi control panel (option)
Unit control via a wired remote LCD control panel
S25 control panel (option)
BMS (Building Management System) RS-485
Blauberg Cloud Server service +
Speed selection +
Filter replacement indication by filter timer
by filter clogging differential pressure switch (only units with DTV)
Alarm indication full alarm description in the mobile application
Week-scheduled operation +
Bypass automatic
Timer +
Boost mode +
Fireplace mode +
Freeze protection through cyclic stops of the supply fan
through preheating (option)
Cooler connection option
Minimum supply air temperature control +
Humidity control option
CO2 control option
VOC control option
PM2.5 control option
Fire alarm sensor connection option

Option: function is available when purchasing the appropriate accessory (see the "Accessories" tab).
Parameter KOMFORT EC DBW 900-E L S21 Measurement unit
Voltage 230 V
Phase 1 ˜
Frequency 50/60 Hz
Max. unit power 442 W
Max. unit current 3 A
Maximum air flow 286 l/s
Maximum air flow 1030 m³/h
Number of water coil rows 2 -
Sound pressure level at 3 m 33 dBА
Insulation 20 mm mineral wool mm
Transported air temperature -25...+40 °С
Extract filter G4 -
Supply filter G4 (Option: F7) -
Heat recovery efficiency 69...85 %
Heat exchanger type counter-flow -
Bypass yes -
Heat exchanger material enthalpy -
Weight 112 kg
Connected air duct diameter 250 mm
Casing material aluzinc -
Type Supply and exhaust -
SEC class A -
Mounting ceiling mounting -
Capacity diagram
Capacity diagram
  • Selection method:
  • Air capacity:
  • Pressure:
Operating point
  • Air capacity: --
  • Pressure: ---
Documents archieve
Documents archieve
Select a document type
  • Catalogues
  • Technical documentation
  • Certificates
S21 - user's manual (pdf 611.32Kb)
KOMFORT EC DBW - data sheet (pdf 2.13Mb)
KOMFORT EC DBW S21 - image (png 318.3Kb)
KOMFORT EC DBW 550 (900) - user's manual (pdf 2.94Mb)
KOMFORT EC DBW 900-E L S21 - energy label (pdf 80.91Kb)
KOMFORT EC DBW 900-E L S21 - specification (pdf 62.42Kb)
Designation key
Designation key
Series   Motor type   Mounting type   Bypass   Heater type   Rated air flow [m³/h]   Heat exchanger type   Service side   Control   Additional elements
KOMFORT   EC: electronically commutated motor   D: suspended mounting, horizontally directed spigots   B: with a bypass   W: water heater   550; 900; 2000; 3000 _: heat recovery

E: energy recovery
  L: left

R: right
  S21   _: no additional elements

DTV: equipped with a differential pressure switch to control filter contamination
    KOMFORT EC DBW 900-Е L S21
G4 panel filter FP 647х274х20 G4
G4 pocket filter FPT 647x274x27 G4
F7 pocket filter FPT 647x274x27 F7
Control panel S22
Wireless control panel S22 Wi-Fi
LCD control panel S25
Humidity sensor FS2
CO₂ sensor with indication CD-1
CO₂ sensor CD-2
Humidity sensor HR-S
Electric preheater EVH 250 S21 V.2
Silencer SD 250
Backdraft air damper VRV 250
Air damper VKA 250
Electric actuator TF230
Water mixing unit WMG

Model Overall dimensions [mm]
Ø D B B1 H L L1
KOMFORT EC DBW 900-E L S21 249 1350 1485 317 1346 1395
Additional characteristics
Additional characteristics
Point Unit power [W]
1 442
2 442
3 442
4 160
5 149
6 147
7 46
8 43
9 40


Sound power level, A-weighted Total Octave frequency band [Hz] LpA 3 m LpA 1 m
63 125 250 500 1000 2000 4000 8000
LwA to supply inlet [dBA] 80 30 64 72 69 74 73 71 71    
LwA to supply outlet [dBA] 70 29 62 69 58 59 53 45 36    
LwA to exhaust inlet [dBA] 78 29 60 69 72 70 71 64 70    
LwA to exhaust outlet [dBA] 69 28 58 68 59 61 56 48 44    
LwA to environment [dBA] 53 33 42 47 49 44 41 39 43 33 43



How to use water heater diagrams.
Sample parameters: Air flow = 950 m³/h.
Outside air temperature = -15 °C.
Water temperature (in/out) = +90/+70 °C.
The air flow is 950 m³/h and the air speed in the heater is 3.35 m/s .

To calculate the maximum air temperature, find the intersection point of the air flow line with the rated outer temperature shown in blue line (e.g., -15 °С) and draw the line to the left until it crosses the water in/out temperature curve (e.g., +90/+70). From this point draw a vertical line to the supply air temperature downstream of the heater (+23 °С) .
  To calculate the heater power, find the intersection point of the air flow with the rated winter temperature shown in red line (e.g., -15 °С) and draw the line to the right until it crosses the water in/out temperature curve (e.g., +90/+70). From this point draw a vertical line to the heater power axis (13.5 kW) . To calculate the required water flow in the heater, prolong this line downwards to the water flow axis (0.14 l/s). To calculate the water pressure drop in the heater, find the intersection point of the line with the pressure loss curve and prolong the line to the right on the water pressure drop axis (1.5 kPa).
AccessoriesSimilar products