Specifications

21
RG SERIES ENGINEERING GUIDE
Controls - FX10 (optional) cont.
Compressor Minimum On Delay
The compressor minimum on delay will ensure that the
compressor output is enabled for a minimum of two (2) minute
each time the compressor output is enabled. This will apply in
every instance except in the event the high pressure switch is
tripped or emergency shutdown then the compressor output will be
disable immediately.
Compressor Short Cycle Delay Time
The compressor short cycle time delay will ensure that the
compressor output will not be enabled for a minimum of five (5)
minutes after it is disabled. This allows for the system refrigerant
pressures to equalize after the compressor is disabled.
Heating Cycle
On a call for heating, the blower enable output and accessory
output 2 will turn on immediately after the random start delay timer
has been satisfied. If the compressor short cycle time delay has
been satisfied, the compressor will turn on after the blower enable
and accessory output 2 are on and the fixed compressor start delay
timers have been satisfied.
Auxiliary heat output can be controlled over the BAS.
Set Point Control Mode
In set point control mode the reversing valve output will be
disabled. As the temperature drops below the heating set
point and begins to operate in the heating proportional band,
the compressor (low capacity for two-stage compressors)
output (BO-2) will be enabled. For units with two-stage
compressors, a PI loop in the programming of the control will
determine when the full capacity compressor output (BO-4)
is to be enabled. The compressor must be operating in low
capacity for a minimum of 30 seconds before the full capacity
compressor output can be enabled. During low capacity
compressor operation the ECM blower will operate in medium
speed and will operate in high speed when the compressor is
operating at full capacity.
Thermostat Control Mode
In thermostat mode the compressor will be cycled based on
Y1 and Y2 calls from a room thermostat. When the control
receives a Y1 command (BI-7) from the thermostat the low
capacity compressor output (BO2) will be enabled and the
ECM blower will operate in medium speed. When the control
receives a Y2 command (BI-8) from the thermostat the ECM
blower will operate in high speed. During the heating cycle the
reversing valve will be commanded into the off position.
Cooling Cycle
On a call for cooling, the blower enable output and accessory
output 2 will turn on immediately after the random start delay timer
has been satisfied. If the compressor short cycle time delay has
been satisfied, the compressor will turn on after the blower enable
and accessory output 2 are on and the fixed compressor start delay
timers have been satisfied.
Set Point Control Mode
In set point control mode the reversing valve output will be
enabled. As the temperature falls below the cooling set point
and begins to operate in the cooling proportional band, the
low capacity compressor output (BO-2) will be enabled. A PI
loop in the programming of the control will determine when the
full capacity compressor output (BO-4) is to be enabled. The
compressor must be operating in low capacity for a minimum
of 30 seconds before the full capacity compressor output can
be enabled. During low capacity compressor operation the
ECM blower will operate in medium speed and will operate in
high speed when the compressor is operating at full capacity.
Thermostat Control Mode
In thermostat mode the compressor will be cycled based on
Y1 and Y2 calls from a room thermostat. When the control
receives a Y1 command (BI-7) from the thermostat the low
capacity compressor output (BO2) will be enabled and the
ECM blower will operate in medium speed. When the control
receives a Y2 command (BI-8) from the thermostat the full
capacity compressor output will be enabled and the ECM
blower will operate in high speed. During the cooling cycle the
reversing valve will be commanded into the “ON” position.
ECM Blower Operation
Blower speeds will be selected through the user interface or the
facility management system. There will be a total of 12 speeds
selectable with only three being selected at any one time. The
lowest numbered speed selection set to ON will select the low-
speed blower setting, the middle selection set to ON will select the
medium-speed blower setting and the highest selection set to ON
will select the high-speed blower setting. If all selections are set to
OFF the software shall select speed setting 10 for low-speed, 11 for
medium-speed, and will select speed setting 12 for high speed. If
only one selection is set to ON, that selection will set the low-speed
blower setting, the medium-speed setting will be 11, and the high-
speed setting will be speed 12. The maximum low-speed setting
will be speed 10 and the minimum high-speed setting will be speed
3. In addition there is a low limit setting in the software to prevent
the ECM blower speed from being set below acceptable limits for
each unit size.
ECM Blower airflow “Soft Switch Settings”
A set of 12 “soft switches” accessible through the user interface
or building automation system are used to select the three blower
speed settings for the ECM blower motor. The 12 soft switches
work in exactly the same way as the hardware switches used on
the Premier control (Refer to Blower Performance Data - ECM
Motor for proper settings). No more than three soft switches may
be set to the “ON” position. The first “ON” switch (the lowest
number switch) determines the “low speed blower” setting. The
second determines the “medium speed blower” setting, and the
third determines the “high speed blower” setting.