Greenheck Fan 470656 Fan User Manual


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Sequence of Operation
8:1 Staged Control
1. Exhaust Fan Contact (S1) Manually Closed
(optional)
• PowerpassesthroughN.C.contactonexhaustfan
overload (ST2 OL), which is closed if exhaust fan
(M2) has not overloaded
• Powerpassestoexhaustfanstarter(ST2)
• N.O.contactonexhaustfanstarter(ST2)is
energized and closed
• Powerpassestoandenergizesexhaustfan(M2)
2. Supply Fan Contact (S2) Manually Closed
• PowerpassesthroughN.C.eld-suppliedre
contact (FSC)
• PowerpassesthroughoptionalN.O.contacton
exhaust fan starter (ST2), which is closed when the
optional exhaust starter (ST2) is activated
• PowerpassesthroughN.C.contactonsupply
starter overload (ST1 OL), which is closed if the
supply fan has not overloaded
• PowerpassesthroughN.C.contactonoptional
freeze protection timer (RT4), which is closed if the
temperature has remained above the set point
• Powerpassestoandenergizesoptionalinlet
damper (D1), which opens
• Powerpassesthroughoptionaldamperlimitswitch
(DL1), which is energized and closed if the optional
inlet damper is open. It may take several minutes
for the damper to fully open and for the damper
limit switch to close
• Powerpassestoandenergizesfanrelay(RF)
• PowerpassesthroughN.O.contactonfanrelay
(RF), which is closed once the fan relay (RF) is
activated
• Powerpassestoandenergizesstarterrelay(ST1)
• N.O.contactonsupplyfanstarter(ST1)is
energized and closed
• Supplyfan(M1)starts
3. Heat Contact (S4) Manually Closed
• PowerpassesthroughN.O.contactonfanrelay
(RF), which is energized and closed if the supply
fan (M1) is on
• Powerpassestoandenergizestheheatrelay(RH)
• N.O.contactonheatrelay(RH)closes
• Thestagecontroller(SC1)comparestheinlet
air temperature to the inlet air set point (iAS, FX
Program Menu). If the inlet air temperature is below
the discharge air setting (dtS, FX Program Menu),
the stage controller sends a call for heat to the
ignition controller (IC1)
4. Ignition Controller (IC1) Sequence of Operation
• TheN.O.contactonairprovingswitch(PS2)is
open
• Thestagecontroller(SC1)energizesthe
combustion blower relay (CR)
• N.O.contactoncombustionblowerrelay(CR)
closes
• Powerpassestoandenergizesthecombustion
blower (CM)
• TheN.O.contactonairprovingswitch(PS2)closes
• Powerpassestoandenergizesairprovingswitch
relay (R9)
• N.O.contactsonairprovingswitch(R9)closes
• Theignitioncontroller(IC)completesa30second
pre-purge
• Themaingasvalve(MV)fullyopens(100%)
• Igniterbeginssparking
• 10secondtrialforignitionbegins
• Thefurnacewilllight
• Thestagecontroller(SC1)willchoosewhichstage
to light the furnace at based on the discharge air
temperature setting (dtS, FX Program Menu) and
the outside air temperature (TS1)
• Whentheameisdetected,theigniterstops
sparking
• Thefurnacewillremainathighre(100%)for20
seconds
• Thestagecontroller(SC1)willstagethemaingas
valves (MV#) as needed between low fire, high fire
and off
• Ifthefurnaceisatlowreandthedischarge
temperature sensor (TS2) reading remains above
the discharge air temperature setting (dtS, FX
Program Menu) for more than six minutes, the
furnace will shut down
5. Staging Control Sequence of Operation
• Ifthedischargetemperature(TS2)isbelowthe
discharge air temperature set point (dtS, FX
Program Menu), the furnace will stage up
• Ifthedischargetemperature(TS2)isabovethe
discharge air temperature set point (dtS, FX
Program Menu), the furnace will stage down
• Ifthedischargetemperature(TS2)isabovethe
discharge air temperature set point (dtS, FX
Program Menu) and the furnace is at low fire, the
furnace will shut off
• Ifthefurnaceisathighreandthedischargeair
temperature setting (dtS, FX Program Menu) is not
satisfied, the furnace will remain at high fire
• Ifthefurnaceisatlowreandthedischargeair
temperature setting (dtS, FX Program Menu) is
satisfied, the furnace will shut off
6. Optional Evaporative Cooling Contact (S4)
Closed*
• N.O.contactonfanrelay(RF)isenergizedand
closed
• PowerpassesthroughN.O.contactonoptional
inlet air sensor (TS4), which is energized and
closed if the inlet air temperature is above the set
point
• Powerpassestoandenergizescoolrelay(RC)
®
Model IG / IGX Make-Up Air
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