8- Whenthecombustionairpost-purgeperiodis com-
plete,theinducerisde-energized.Theindoorblower
isde-energizedattheendoftheoffdelay.
ApplicationsUsingASingle-StageThermostat
C- HeatingSequence-- ControlThermostatSelection
DIPswitchin "Single-Stage"Position
1- Onacallforheat,thermostatfirst-stagecontactsclose
sendinga signalto theintegratedcontrol.Theinte-
gratedcontrolrunsa self-diagnosticprogramand
checkshightemperaturelimitswitchesfornormally
closedcontactsandpressureswitchesfor normally
opencontacts.Thecombustionair induceris ener-
gizedattheignitionspeed,whichisapproximatelythe
sameastheinducerspeedat70percentfiringrate.
2- Oncethecontrolreceivesa signalthatthelow-fire
pressureswitchhasclosed,thecombustionairinduc-
erbeginsa15-secondpre-purgeattheignitionspeed.
3- Afterthepre-purgeiscomplete,a20-secondinitialig-
nitorwarm-upperiodbegins,Thecombustionairin-
ducercontinuestooperateattheignitionspeed,
4 - Afterthe20-secondwarm-upperiodhasended,the
gasvalveisenergizedandignitionoccurs,whichiniti-
atesa 10-secondignitionstabilizationdelay.At the
sametime,thecontrolmodulesendsasignaltobegin
an indoorblower45-secondON-delay.Whenthe
delayends,theindoorblowermotorisenergizedata
speedwhichisappropriateforthefiringrate.Afterthe
10-secondignitionstabilizationdelayexpires,thein-
ducerspeedisadjustedto40percentspeed.Theinte-
gratedcontrolalsoinitiatesasecond-stageondelay
(factory-setat7 minutes;adjustableto 12minutes).
5- Iftheheatingdemandcontinuesbeyondthesecond-
stageondelay,theintegratedcontrolenergizesthe
combustionairinducerat 70percentspeed.Thein-
doorblowermotoris adjustedto a speedwhich
matchesthetargetrate.Afixed,10-minutethird-stage
ondelayisinitiated.
6- If theheatingdemandcontrinuesbeyondthethird-
stageondelay,theintegratedcontrolenergizesthein-
ducerathighspeed.Theindoorblowermotorisad-
justedtoa speedwhichis appropriateforthetarget
rate.
7 -Whenthethermostatheatingdemandissatisfied,the
gasvalveisde-energizedandthecombustionairin-
ducerbeginsa 20-secondpost-purge.Thefield-se-
lectedindoorbloweroffdelaybegins.
8- Whenthecombustionairpost-purgeperiodis com-
plete,theinducerisde-energized.Theindoorblower
isde-energizedattheendoftheoffdelay.
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