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RC SERIES INSTALLATION MANUAL
Compressor Fixed On Delay Time
The Compressor Fixed On Delay Time will ensure that the
compressor output (B02) is not enabled for (90) seconds after
the control receives a call to start the compressor. This delay is
adjustable from 30 – 300 seconds over a BAS or a MUI. If the
control is in test mode the Compressor Fixed On Delay Timer will
be shortened to 5 seconds.
Compressor Minimum On Delay
The compressor minimum on delay will ensure that the
compressor output is enabled for a minimum of (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 (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 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 ECM2 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 ECM2 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
ECM2 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 ECM2 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 ECM2 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
ECM2 blower will operate in high speed. During the cooling
cycle the reversing valve will be commanded into the “ON”
position.
ECM2 Blower Operation
Fan 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 fan setting, the middle selection set to ON will select the
medium-speed fan setting and the highest selection set to ON
will select the high-speed fan 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 fan 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 ECM2 fan speed from being set below acceptable limits
for each unit size.
Controls - FX10 cont.
