Danfoss Termix VVX-I - Troubleshooting; General Troubleshooting Checks; DHW Troubleshooting Guide

InstallationGuideTermixVVX-I
7.0Troubleshooting
7.1Troubleshootingingeneral
Intheeventofoperatingdisturbances,thefollowingbasicfeatures
shouldbecheckedbeforecarryingoutactualtroubleshooting:
•thesubstationisconnectedtoelectricity,
•thestrainerontheDHsupplypipeisclean,
•thesupplytemperatureoftheDHisatthenormallevel
(summer,atleast60°C-winter,atleast70°C),
•thedifferentialpressureisequaltoorhigherthanthenormal
(local)differentialpressureintheDHnetwork–ifindoubt,ask
theDHplantsupervisor,
•pressureonthesystem-checktheHEpressuregauge.
Authorizedpersonnelonly
Assembly,start-upandmaintenanceworkmustbeperformedby
qualiedandauthorizedpersonnelonly.
7.2TroubleshootingDHW
ProblemPossiblecauseSolution
Strainerinsupplyorreturnlineclogged.Cleanstrainer(s).
DHWcirculationpumpoutoforderorwith
toolowsetting.
Checkcirculationpump.
Defectiveorcloggednon-returnvalve.
Replace–clean.
Noelectricity.Check.
Wrongsettingofautomaticcontrols,ifany.Toadjustanelectroniccontrollerfor
DHW,pls.noteenclosedinstructionsfor
electroniccontroller.
Scalingoftheplateheatexchanger.
Replace–rinseout.
Defectivemotorizedvalve.Check(usemanualfunction)–replace.
Defectivetemperaturesensors.
Check–replace.
ToolittleornoDHW.
Defectivecontroller.
Check–replace.
DCWisbeingmixedwiththeDHW,e.g.in
adefectivethermostaticmixingvalve.
Check–replace. Hotwaterinsometapsbutnotinall.
Defectiveorcloggednon-returnvalveon
circulationvalve.
Replace–clean.
Taptemperaturetoohigh;DHWtapload
toohigh.
Thermostaticvalveadjustedtoatoohigh
level.
Check–set.
Scalingoftheplateheatexchanger.
Replace–rinseout. Temperaturedropduringtapping.
LargerDHWowthanthesubstationhas
beendesignedfor.
ReduceDHWow.
Thermostaticcontrolvalvedoesnotclose
TemperaturedifferencebetweenDH
supplyandDHWsetpointtoolow.
Lowerthesetpointtemperatureor
increasetheDHsupplytemperature.
Idletemperaturetoolow(forstations
equippedwithIHPT).
Setpointtoolow.Turnthermostatin(+)direction.
DanfossDistrictEnergy
VI.EH.G3.02/LUK40440
DEN-GT
17