MAXA HI-T - Measurement of Temperature and Humidity; Dew Point and Dehumidufucation Control

Hi‐TCentralizedcontroller
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Note:Ifinthechillerisconfiguredthepresenceofadigitalinputtothemanagementofthesecondsetpoint(chillerparameterH44
=26,terminalsSE‐SE,ref.Chillermanual),themanagementofthehumiditycontrolisnotdonefromtheremotecontrol.
Thedigitalinputisalso
possiblyusedforswitchbetweenthefirstandsecondsetpointduringoperationinwintermode.
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Withdoubleset‐point functionenabled,ifthechillerworksonthesecondset‐point(radiantpanelsside),thedoubleset‐pointicon
appearsinthetoolbarofthefunctionsinthepagesof
chillersandfancoilsanditremainstransparent.
If,however,thechillerswitchtothermoregulateonthefirstset‐point(fancoilside),thedoubleset‐pointiconappearscolourful.
Similarly,the entryintodehumidificationis markedinthe functionbarofchillers andfan coilsbythe transitionfromtransparent
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icontocolourfulicon.
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WithparametersH82>1:
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FLOORSIDEFUNCTION
(2°SET‐POINT)
FANCOILSIDEFUNCTION
(1°SET‐POINT)
DOUBLESET‐POINTICON
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ICONDEHUMIDIFICATION
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ifdehumidificationisactive
Table8.Doubleset‐point/dehumidificationicon.
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Inaddition, inthe homepage,youwill see avisual indicationof activationofthefan coildehumidification
(seeFigure 9.Fan coil
dehumidification.).
4.9.1 MEASUREMENTOFTEMPERATUREANDHUMIDITY
TheambienttemperatureandtherelativehumiditymeasuredbythesensorsbuiltintotheHi‐Tremotecontrol,areavailabletothe
chiller,whichcanthenusethesevaluesmeasuredfortheirregulators,whererequired.
4.9.2 DEWPOINTANDDEHUMIDUFUCATIONCONTROL
Giventheenvironmentaltemperatureandthehumidity,theHi‐Tremotecontrolcalculatesthedewpoint.
In operation of the plant in summer mode, with the double set‐point function active on chillers and thermoregulation normally
madewiththeradiantpanels(secondsetofwork),itactivatesacontroltokeep
thedewpointofatleastaquantitydefinedbythe
keyboardmaintainerparameterPar42/44:"Dew‐pointtemp.margin"°Cbelowtheambienttemperaturedetectedbythecontrol
itself.
Instead,whenambienttemperature<DewPoint+Margintemp.Point:
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• Thefancoilsfordehumidificationturn
on.
• Thechillerstartworkingwiththeset‐pointforthefancoils.
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Thepermanenceremainsinthisstatusuntilthetemperaturereturnsto:
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Ambienttemperature≥Dewpoint+Dewtemp.margin+1°C.
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Even in the case where the above condition is verified, it remains in the status of dehumidification for at least the time set by
maintainerparameterPar43/44:"Min.
stayingtimeindehumidification",inordertoavoidannoyingoscillations.
Iftheaboveconditionis notsatisfiedafteramaximumtime givenbythemaintainerparameterPar44/44:"MaxDehumidification
time",themachinecomesoutfromdehumidification.Toavoidreturningimmediately,inthiscaseitrequiresaminimum
stayingin
adjustmenttotheradiantpanels,stillgivenbyPar43/44:"Max.stayingtimeindehumidification".
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