Lennox MPA009S4S - Electronic Expansion Valve (EXV) Control

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31.7. Electronic Expansion Valve (EXV) Control
a. EXVwillbefullyclosedwhenturningonthepower.ThenEXVwillbestandbywith350Popenandwillopentotarget
angle after compressor starts.
b. EXVwillclosewith-160Pwhencompressorstops.ThenEXVwillbestandbywith350Popenandwillopentotarget
angle after compressor starts.
c. TheactionpriorityoftheEXVsisA-B-C-D.
d. CompressorandoutdoorfanstartoperationonlyafterEXVisinitialized.
31.7.1. Cooling mode
TheinitialopenangleofEXVis250P,adjustmentrangeis100-350p.Whentheunitstarttoworkfor3minutes,theoutdoor
willreceiveindoorunits(ofcapacitydemand)T2Binformationandcalculatetheaverageofthem.Aftercomparingeach
indoor’sT2Bwiththeaverage,theoutdoorgivesthefollowingmodicationcommands:IftheT2B>average,therelevant
valveneedsmore16popen;IftheT2B=average,therelevantvalve’sopenrangeremains;IftheT2B<average,therelevant
valve needs more 16p close.
Thismodicationwillbecarriedoutevery2minutes.
31.7.2. Heating mode
The initial open angle of EXV is 250P, adjustment range is 100-350p. When the unit start to work for 3 minutes, the
outdoorwillreceiveindoorunits(ofcapacitydemand)T2informationandcalculatFrom SubjectReceived Size
Categories
After comparing each indoor’s T2 with the average, the outdoor gives the following modication commands: If the
T2>average+2,therelevantvalveneedsmore16pclose;
Ifaverage+2≥theT2≥average-2,therelevantvalve’sopenrangeremains;
IftheT2<average-2,therelevantvalveneedsmore16popen.
Thismodicationwillbecarryoutevery2minutes.