Heating, Unit With Economi$Er; Cooling, Unit With Economi$Er2, Premierlink Control And A Thermostat - Carrier WeatherMaker 50TCQ Product Data

up to 30 seconds to initiate. Damper movement from full
closed to full open (or vice versa) will take between 1
1
and 2 / minutes.
2
If free cooling can be used as determined from the
appropriate changeover command (switch, dry bulb,
enthalpy curve, differential dry bulb, or differential
enthalpy), then the control will modulate the dampers
open to maintain the mixed air temperature setpoint at
50_ to 55_F (10_ to 13_C).
If there is a further demand for cooling (cooling second
stage — Y2 is energized), then the control will bring on
compressor stage 1 to maintain the mixed air temperature
setpoint. The EconoMi$er IV damper will be open at
maximum position. EconoMi$er IV operation is limited to
a single compressor.

Heating, unit with EconoMi$er

When the room temperature calls for heat through
terminal W1, the indoor (evaporator) fan contactor (IFC)
and heater contactor no. 1 (HC1) are energized and the
reversing valve(s) de- - energize and switches position. On
units equipped for 2 stages of heat, when additional heat is
needed, heater contactor no. 2 is energized through W2.
The economizer damper moves to the minimum position.
When the thermostat is satisfied, the damper moves to the
fully closed position.
Cooling, unit with EconoMi$er2, PremierLink
control and a thermostat
When free cooling is not available, the compressors will
be controlled by the PremierLink control in response to
the Y1 and Y2 inputs from the thermostat.
The PremierLink control
information to determine if free cooling is available:
S Indoor fan has been on for at least 30 seconds.
S The SPT, SAT, and OAT inputs must have valid
readings.
S OAT must be less than 75_F (24_C).
S OAT must be less than SPT.
S Enthalpy must be LOW (may be jumpered if an
enthalpy sensor not available).
S Economizer position is NOT forced.
Pre- - cooling occurs when there is no call from the
thermostat except G. Pre- - cooling is defined as the
economizer modulates to provide 70_F (21_C) supply air.
When free cooling is available the PremierLink control
will control the compressors, energize the reversing
valve(s) and economizer to provide a supply air
temperature determined to meet the Y1 and Y2 calls from
the thermostat.
If optional power exhaust is installed, as the outdoor air
damper opens and closes, the power exhaust fans will be
energized and de- - energized.
1
/
2
will use the following
If field- - installed accessory CO
the PremierLink control, a PID controlled demand
ventilation strategy will begin to operate. As the CO
level in the zone increases above the CO
minimum position of the damper will be increased
proportionally. As the CO
2
increase in fresh air, the outdoor air damper will be
proportionally closed.
Heating, unit with EconoMi$er2, PremierLink
control and a thermostat
When the thermostat calls for heating, terminal W1 is
energized. The PremierLink control will move the
economizer damper to the minimum position if there is a
call for G and closed if there is a call for W1 without G.
In order to prevent thermostat from short cycling, the unit
is locked into the heating mode for at least 10 minutes
when W1 is energized. The reversing valve solenoid(s)
de- - energizes and switches position.
On units equipped for two stages of heat, when additional
heat is needed, W2 is energized and the electric heat (if
used) comes on. When the thermostat is satisfied and W1
is de- - energized, the IFM stops.
Cooling, unit with EconoMi$er2, PremierLink
control and a room sensor
When free cooling is not available, the compressors will
be controlled by the PremierLink controller using a PID
Error reduction calculation.
The PremierLink controller will use the following
information to determine if free cooling is available:
S Indoor fan has been on for at least 30 seconds.
S The SPT, SAT, and OAT inputs must have valid
readings.
S OAT must be less than 75_F (24_C).
S OAT must be less than SPT.
S Enthalpy must be LOW (may be jumpered if an
enthalpy sensor is not available).
S Economizer position is NOT forced.
When free cooling is available, the outdoor air damper is
positioned through the use of a Proportional Integral (PID)
control process to provide a calculated supply air
temperature into the zone. The supply air will maintain
the space temperature between the heating and cooling
setpoints.
The PremierLink control will integrate the compressors
stages with the economizer based on similar logic as the
three routines listed in the previous section. The SASP
will float up and down based on the error reduction
calculations that compare space temperature and space
setpoint. The reversing valves will be energized.
If an optional power exhaust is installed, as the outdoor air
damper opens and closes, the power exhaust fans will be
energized and de- - energized.
94
sensors are connected to
2
setpoint, the
2
level decreases because of the
2