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8 - Whenthecombustion a ir post-purge p eriodis com-
plete, t heinducer i s de-energized. Theindoorblower
is de-energized attheendoftheoffdelay.
ApplicationsUsingA Single-Stage T hermostat
C - HeatingSequence -- Control T hermostat S election
DIPswitchin "Single-Stage"Position
1 - Ona call f orheat, t hermostat first-stage c ontacts c lose
sending a signal t o theintegrated control. T heinte-
gratedcontrolrunsa self-diagnostic program and
checkshightemperature l imitswitches for normally
closed contacts andpressure switches for normally
opencontacts.The c ombustion air induceris ener-
gized attheignition s peed, w hich isapproximately the
sameastheinducer s peed at70percent firingrate.
2- Oncethe control r eceives a signalthatthe low-fire
pressure s witch hasclosed, thecombustion airinduc-
er begins a 15-second pre-purge attheignition speed.
3 - Afterthepre-purge i s complete, a 20-second i nitial i g-
nitorwarm-up periodbegins, T hecombustion a ir in-
ducercontinues t ooperate attheignition speed,
4 - Afterthe20-second w arm-up periodhasended, t he
gasvalveisenergized a ndignition occurs, whichiniti-
atesa 10-second i gnition stabilization d elay.At the
sametime, t hecontrol module sends a signal t obegin
an indoorblower45-second ON-delay. W henthe
delayends, t heindoor b lower m otor is energized a ta
speed which isappropriate forthefiringrate. A fterthe
10-second i gnition stabilization d elay expires, t hein-
ducerspeed isadjusted to40percent speed.The i nte-
gratedcontrol alsoinitiates a second-stage ondelay
(factory-set at7 minutes; adjustable t o 12minutes).
5 - Iftheheating demand continues b eyond thesecond-
stageon delay,the integrated c ontrol e nergizes t he
combustion a irinducer a t 70percent s peed.Thein-
door blowermotor is adjustedto a speedwhich
matches t hetarget r ate.Afixed,10-minute third-stage
ondelayis initiated.
6 - If the heating demandcontrinues b eyondthe third-
stageondelay, t heintegrated control energizes thein-
ducerat highspeed. T heindoor b lowermotoris ad-
justedto a speed whichis appropriate f orthe target
rate.
7 -When thethermostat heating demand is satisfied, the
gasvalveisde-energized andthecombustion a irin-
ducerbegins a 20-second p ost-purge. Thefield-se-
lectedindoor b lower o ffdelaybegins.
8 - Whenthe combustion a ir post-purge p eriodis com-
plete, t heinducer i s de-energized. Theindoor b lower
is de-energized attheendoftheoffdelay.
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