Centrifugal roof fan

GRD 31

Article number: 0087.0018
Manufacturer: MAICO
Centrifugal roof fans with EC motor with integrated control for constant pressure or constant volumetric flow,... more information
Application examples: Central air extraction from multiple family living units in combination with Centro exhaust air elements.
GRD 31 IM0009963.PNG Centrifugal roof fans with EC motor with integrated control for constant pressure or constant volumetric flow, DN 315
GRD 31 IM0013704.PNG Centrifugal roof fans with EC motor with integrated control for constant pressure or constant volumetric flow, DN 315

Characteristic curve

GRD 31 - Characteristic curve

Dimensioned drawing

GRD 31 - Dimensioned drawing [mm]

  1. Clear width
  2. External duct diameter
  3. Number of holes: 8

Technical data

GRD 31 - Technical data

Article GRD 31
Air flow volume 3.600 m³/h
Air volumenom 2.020 m³/h / in opt. efficiency
Pressure pfs, nom 380 Pa / in opt. efficiency
Rotating speed nnom 1.490 1/min / in opt. efficiency
Rotating speed 1.732 1/min
Impeller type radial
Speed controllable
Reversing capacity
Rated voltage 230 V
Frequency 50 Hz
Nominal output 600 W / in opt. efficiency
Inom 3,5 A / in opt. efficiency
Imax 3,6 A
Degree of protection IP 45
Insulation class B
Mains cable 3 / 1,5 mm²
Installation site Roof
Installation position vertical
Material Sheet steel, galvanised
Weight 42,3 kg
Shutter integrated
Type of shutter Airstream-operated opening/closing
Nominal size 315 mm
Width 724 mm
Height 724 mm
Depth 547 mm
Airstream temperature at nominal current -20 °C up to 50 °C
Airstream temperature at IMax -20 °C up to 50 °C
Packing unit 1 piece
Range C
GTIN (EAN) 4012799870180
Article number 0087.0018
Article GRD 31
Total efficiency η 48,8 %
Measurement category C
Efficiency category static
Efficiency level N 65,6
VSD necessary integrated VSD
Year of manufacture see rating plate
Manufacturer’s name / official registration number / manufacturer's place of establishment Maico Elektroapparate-Fabrik GmbH / Freiburg registration court, HRB 601233
Art. No. 0087.0018
PBEP / Air volumeBEP / Pfs, BEP 0,255 kW / 1.690 m³/h / 432 Pa
nBEP 1.102 1/min
Specific ratio ≈ 1
Information about dismantling and disposal see mounting instructions
Information about installation, operation and repairs see mounting instructions
Objects used to measure efficiency which are not described by the measurement category Calculation of energy efficiency without housing.
Sound power levelLWA5 74 dB(A)


63 Hz

125 Hz

250 Hz

500 Hz

1 kHz

2 kHz

4 kHz

8 kHz


LWA5, high (dB(A))










LWA8, high (dB(A))










LWA5= free inlet sound power level in dB.

LWA8= housing and free outlet sound power level in dB.

Product description


GRD 31

short description

Centrifugal roof fans with EC motor with integrated control for constant pressure or constant volumetric flow, DN 315

Product description


  • Pressure or volumetric constancy can be set.
  • 2 speed levels for day/night operations.
  • Day/night operation can be set using 2 reference volumetric flows or 2 reference pressure levels.
  • With automatic fault message.
  • Can be used for central ventilation systems in accordance with DIN 18017-3.
  • Adjustments can be undertaken without pressure or volumetric flow having to be measured.
  • Housing easily detachable for cleaning purposes.
  • Galvanized protective grille on the discharge side, protection against accidental contact in accordance with DIN EN ISO 13857.
  • Sturdy eyebolts enable transport by crane.
  • Impeller with blades curved to the rear, dynamically balanced at two levels, in accordance with performance level 6.3, DIN ISO 1940.
  • Impeller made of glass-fibre filled polypropylene.
  • With service switch.
  • IP 45 degree of protection.

Control unit

  • Control unit included in scope of delivery.
  • Any installation inside the building.
  • Pressure sensor fitted in fan housing ready for use.
  • Control unit for operating in constant pressure / constant volumetric flow mode.
  • A minimum volumetric flow is required for the correct function:
    • GRD 22 - 150 m3/h
    • GRD 25 - 200 m3/h
    • GRD 31 - 250 m3/h


  • EC motor.
  • Overload protection as standard.
  • No motor protection measures needed.

Electrical connection

  • 2 separate mains connections (230 V, 50 Hz) needed for fan and control unit.
  • Mains connections 3 x 1.5 mm2 each, type NYM-J / NYM-O.
  • 6-core shielded control cable between control and fan.
  • Control cable with maximum length of 200 m, maximum external diameter of 6 mm, e.g. LiYCY (6 x 0.25 mm2 or 6 x 0.34 mm2).

Table of contents

Wiring diagram

GRD 31 - Wiring diagram

B - Control

W3 - Power cable control (provided by customer)

K1 - Closed soft start

K1 - Open soft stop

K3 - Closed reduction mode active (e.g: night-time operation)

K3 - Open reduction mode inactive

* - Attention: use K1, K3 gold-plated contacts

A - GRD unit

W1 - Power cable for GRD unit 1.5mm² (provided by customer)

W2 - Control cable with sheathing of 0.25 to 0.34mm² (provided by customer)

M - Fan motor

S1 - Service switch

Predecessor - successor

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