IMO MRH

Electrical connection
MRH 18.08.2022 9
 Avoid distortions of the casing at installation. Check the air gap impeller/housing after fixing the MRH, the mini-
mum air gap should remain over allowed minimum from the fan`s test protocol.
 Ensure unobstructed and uniform intake into the fan as well as free outlet.
 Install connecting ducts and accessories. The suction side of the fan is provided with a connection for flange-type
mounting of the air duct according Eurovent 1/2, dimensions see Appendix 1 or
www.systemair.com.
 Provide for contact/suction protection and safety distances according to EN ISO 13857.
 Provide flashing. Remove lifting eyes and store them.
NOTE
In some cases, it is better to mount accessories before placing the MRH on the roof.
NOTE
It is recommended to install a flexible connection between the fan and duct to avoid eventual tensions or
distortions of the casing (appropriate flexible connection should take eventual thermal extension of con-
necting parts). Flexible connection has to comply needed temperature/time; also as certified Systemair
accessory available.
NOTE
Data of accessories are on-line available (www.systemair.com).
7 Electrical connection
Fan: the wiring diagram of the fan is placed inside the cover of service switch. The quality and installation of cables for
electrical connection must ensure uninterrupted energy supply, even in case of fire. Inside fire zone, use only certified
cable. Connecting possibility see Appendix 3. Electrical data on the fan`s nameplate must comply with the provided
mains connection. Voltage tolerance according to IEC 38: +6%, -10%.
Hatch cover: it is opened by one or two 24 VDC operated spindle actuators with push rod. Indication for
opened/closed cover position possible (floating limit switches in actuator). Connection of the hatch cover drive in the
actuator`s service switch powered by 24 VDC (see Appendix 4) or optionally in control box with service switch pow-
ered with 230 VAC (see Appendix 5). The wiring diagram of the hatch cover is placed inside the cover of service
switch/control box. Details see Appendix 4/5.
Proper application circuit shall include safety precautions such as protective fuse and an adequate electrical insula-
tion arrangement!
The recommended start of the fan is 20 s after starting actuator for cover opening, to ensure vertical exhaust of hot
gases.
NOTE
 If the fan motors have built-in PTC: more than two PTC chains may not be switched in series, as this can
lead to undefined cut-outs.
 Maximum check voltage of PTC is 2,5 V (to reduce influence on the result of measurement).
 The wiring diagram see Appendix 3.
 Motor protection must be provided by the installer.
 At AXC(F) and AXC(B) fans without PTC observe specific instructions of the fan.