KA IMO 2021 6 V2.1

systemair 35
Commissioning
• Beforecheckingthecorrectfaninstallationandoperation,switchofftherepairswitchofthefansectioninwhich
you intend to intervene, or alternatively switch off the main switch on the air handling unit electric control cabinet,
andlocktheswitchintheoffposition,tobreakthecurrentsupplycircuittothedriveelectricmotor.
• Priortostartingtheelectricmotor,removeanymechanicalinterlocksonvibrationisolators.
• The fan must not be operated if the door of the fan unit is open.
• Bymeansofapulsestart,checkthecorrectdirectionofthefanrotation.Therotormustrotateinthedirectionof
the arrow on its casing. In the event of an incorrect direction of rotation, switch two phases on the contactor. The
procedureforcheckingthedirectionofrotationmustbecarriedoutwiththefansectiondoorclosed.Observethe
direction of rotation through the service door inspection window, with the lamp in the section on.
• Aftertherststart,measuretheelectricmotorcurrent.Iftheelectriccurrentislessthanorequaltothenominal
current,youmayproceedtosetuptheairvolumeowrate.
• Theairvolumeowrateisadjustedbychangingtheposition(openingorclosing)ofthecontroldampers.Once
theairvolumeowrateissetup,measuretheelectricmotorcurrentagain.Anelectriccurrentlowerthanorequal
to the nominal current indicates the correct operation of the fan section. If the motor current exceeds the nominal
value, shut down the electric motor and establish the cause of its incorrect operation.
Causes and corrections
The possible causes are the following: an incorrect motor connection, an incorrect supply voltage, an incorrect supply
frequency, incorrect electric leads, an incorrectly selected size of the electric motor, incorrect pressure drops, an excess
airvolumeowrate.
Inordertocorrecttheairvolumeowrate,reducetheelectricmotorrevolutionsbymeanschangingthepulleyonthe
motor and/or the pulley on the fan. In order to correct the pressure levels, adjust the control dampers.
After remedying all the causes of incorrect operation, measure the electric motor current again. An electric current lower
than or equal to the nominal current indicates the correct operation of the fan section.
Forroomswithanexcesssupplyair,anyfailureoftheintakeairfanmustresultintheautomaticshutdownofthe
dischargeairfan,too,inordertopreventanyreversaloftheairowfromtheroomtotheneighbouringrooms.Ifexcess
dischargeairisrequired,theinterlocklogicoftheprecedingsentenceisreversed.
Inthecaseoftheuseofairrecirculationinhygienic-typeairhandlingunits,checkwhetherthereareanyhygienic-
toxicological concerns associated with the contamination of the supply air by harmful gases, i.e. whether the use of air
recirculation is allowable at all.
Caution
Duringoperation,allthecoversandservicedoorsofthesectionmustbekeptclosedatalltimes.Thefan
may not operate with the fan section door open.
Prior to any intervention in the fan section, switch off the repair switch on the fan section in which you intend to
intervene,andlocktheswitchintheoffposition,inordertobreakthecurrentsupplycircuittothedriveelectricmotor.
Propermaintenanceisalsoaprerequisiteforsafeunitoperation.Regularlycheckthetightnessofallthethreadedjoints,
electrical connection terminals, grounding and section casing sealing.
Overloads and excessive temperatures may damage the bearings and lead to excessive operating noise. Replace
damaged bearings.
Withpropermaintenance,approx.20,000hoursofservicelifeofthebearingscanbeachievedataminimum;the
specicservicelifevalueisquotedbythefanmanufacturer.
Check monthly
• The mounting of the rotor on the shaft,
• the tightness of all the threaded joints,
• the rotor run,
• the vibration isolators of the fan-electric motor assembly,
• theexibleconnections,and
• theshaftbearings;ifaxialshiftsofshaftsinthebearingsaredetected,consultthefanmanufacturerandremedy
the fault.