NOTES:
1. In heating mode, economizer damper blade will move to the mini-
mum position, and unit will operate as described for units without
economizer, regardless of outdoor air temperature.
2. The temperatures given in the graph are for demonstration pur-
poses only and may vary depending on which thermostat is used.
LEGEND
C—Contactor
HC — Heater Contactor
IFC — Indoor-Fan Contactor
OAT — Outdoor-Air Thermostat
OFC — Outdoor-Fan Contactor
RVS — Reversing Valve Solenoid
W—Heating Stage
X—Contact Energized
Y—Cooling Stage
UNITS WITH ECONOMIZER
AVERAGE OUTDOOR-AIR TEMPERATURE GREATER THAN OAT SETTING
Thermostat Demand G Y1 Y2 W1 W2 C1 C2 IFC OFC RVS1 RVS2 HC
Second Stage Cooling XX X X X X X X X
First Stage Cooling XX X X X X X
Deadband (Offset)
First Stage Heating XXXX
Second Stage Heating XXXXX X
AVERAGE OUTDOOR-AIR TEMPERATURE LESS THAN OAT SETTING, BUT GREATER THAN −2 C (28 F)
Thermostat Demand G Y1 Y2 W1 W2 C1 C2 IFC OFC RVSI RVS2 HC
Second Stage Cooling XX X X X X X X
First Stage Cooling XX X X X
Deadband(Offset)
First Stage Heating XXXX
Second Stage Heating XXXXX X
UNITS WITHOUT ECONOMIZER
AVERAGE OUTDOOR-COIL TEMPERATURE LESS THAN −2C (28 F)
Thermostat Demand G Y1 Y2 W1 W2 C1 C2 IFC OFC RVSI RVS2 HC
Second Stage Cooling XX X X X X X X X
First Stage Cooling XX X X X X X
Deadband (Offset)
First Stage Heating XXXX
Second Stage Heating XXXXX X
AVERAGE OUTDOOR-COIL TEMPERATURE GREATER THAN −2 C (28 F)
Thermostat Demand G Y1 Y2 W1 W2 C1 C2 IFC OFC RVSI RVS2 HC
Second Stage Cooling XX X X X X X X X
First Stage Cooling XX X X X X X
Deadband (Offset)
First Stage Heating XXXX
Second Stage Heating XXXXX X
Fig. 20 — Typical Operating Sequence
18
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