Greenheck Fan Part #470655 Electric Heater User Manual


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DGX Industrial Space Heating
Operation - Electrical Sequence
With 7-Day Timer
1. Switch (S2) in Summer Mode
• PowerpassesthroughN.C.eld-suppliedre
contact (FSC)
• PowerpassesthroughterminalG
• 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toandenergizesfanrelay(RF)
• PowerpassestoN.O.contactonfanrelay(RF),
which closes once the fan relay (RF) is activated
• Powerpassestoandenergizessupplyfanstarter
(ST1)
• N.O.contactonsupplyfanstarter(ST1)is
energized and closed
• Supplyfan(M1)starts
2. Switch (S2) in Winter Mode
• Ifspacetemperatureislessthanthedaytime
temperature setting, the N.O. contact on the
temperature sensor (TS1) closes and power passes
to the timer (TC1). If the timer (TC1) is on, power
passes through N.C. field-supplied fire contact
(FSC). If the timer (TC1) is off, but the space
temperature is less than the nighttime temperature
setting, the N.O. contact on the temperature sensor
(TS2) closes and power passes through N.C. field-
supplied fire contact (FSC)
• PowerpassesthroughterminalW1andthen
energizes the space heat relay (RS)
• PowerpassesthroughN.O.contactonthespace
heat relay (RS), which is energized and closed
• PowerpassesthroughterminalG
• 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toandenergizesfanrelay(RF)
• PowerpassestoN.O.contactonfanrelay(RF),
which closes once the fan relay (RF) is activated
• Powerpassestoandenergizessupplyfanstarter
(ST1)
• N.O.contactonsupplyfanstarter(ST1)is
energized and closed
• Supplyfan(M1)starts
• PowerpassesthroughN.O.contactonfanrelay
(RF), which is energized and closed
• Powerpassestoandenergizestheheatrelay(RH)
• PowerpassesthroughN.O.contactonheatrelay
(RH), which is energized and closed
• Powerpassestoandenergizesterminal5onthe
Flame Safeguard (FSG)
• PowerpassesthroughN.C.contactonhigh
temperature limit control (HLC1), which remains
closed if the temperature has remained below the
HLC1 set point
• PowerpassesthroughoptionalN.C.andN.O.high
and low gas pressure contacts (PS4 and PS3),
which are both closed if the gas pressure is within
the set range
• Powerpassestoterminal6ontheFlameSafeguard
(FSG)
• FlameSafeguard(FSG)beginsdirectgasburner
sequence (See Flame Safeguard Sequence)
3. Flame Safeguard (FSG) Sequence
• Veriesproperairowwithairowswitch(PS2)
• Veriesnoameispresentatburner
• Initiates10secondprepurge
• Sendspowertoopenpilotvalve(V1)andenergizes
the spark generator (SG) (clicking of the spark
generator may be heard)
• Energizessparkgeneratorforupto10secondsto
light pilot and confirm flame
• Powersthemaingasvalve(V2)open
• Shutsdownsparkgenerator(SG)
• Continuouslymonitorstheameandairow
• Performsself-diagnosticcheckeveryfourseconds
®
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