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If an optional power exhaust is installed, as the outdoor air damper
opens and closes, the power exhaust fans will be energized and
deenergized.
If field-installed accessory CO
2
sensors are connected to the
PremierLink control, a PID-controlled demand ventilation strate
-
gy will begin to operate. As the CO
2
level in the zone increases
above the CO
2
set point, the minimum position of the damper will
be increased proportionally. As the CO
2
level decreases because of
the increase in fresh air, the outdoor air damper will be proportion
-
ally closed.
Heating Unit with EconoMi$er2, PremierLink
Control and a Room Sensor
Every 40 seconds the controller will calculate the required heat
stages (maximum of 3) to maintain supply air temperature (SAT)
if the following qualifying conditions are met:
• Indoor fan has been on for at least 30 seconds.
• COOL mode is not active.
• OCCUPIED, TEMP. COMPENSATED START or HEAT
mode is active.
• SAT reading is available.
• Fire shutdown mode is not active.
If all of the above conditions are met, the number of heat stages is
calculated; otherwise, the required number of heat stages will be
set to 0.
If the PremierLink controller determines that heat stages are re
-
quired, the economizer damper will be moved to minimum posi
-
tion if occupied and closed if unoccupied.
Staging should be as follows:
IF HEATING PID STAGES=2
• HEAT STAGES=1 (50% capacity) will energize HS1
• HEAT STAGES=2 (100% capacity) will energize HS2
IF HEATING PID STAGES=3 AND AUXOUT=HS3
• HEAT STAGES=1 (33% capacity) will energize HS1
• HEAT STAGES=2 (66% capacity) will energize HS2
• HEAT STAGES=3 (100% capacity) will energize HS3
In order to prevent short cycling, the unit is locked into the heating
mode for at least 10 minutes when HS1 is deenergized. When HS1
is energized, the induced draft motor is then energized and the
burner ignition sequence begins. On units equipped for two stages
of heat, when additional heat is needed, HS2 is energized and
the high-fire solenoid on the main gas valve (MGV) is ener
-
gized. When the space condition is satisfied and HS1 is
deenergized, the IFM stops after a 45 second time-off delay,
unless in the occupied mode. The fan will run continuously in
the occupied mode as required by national energy and fresh air
standards.