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ASTON COMPACT 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 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.
NOTE:
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 variable
speed 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
variable speed ECM blower will operate in medium speed.
When the control receives a Y2 command (BI-8) from the
thermostat the variable speed 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 rises above 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
variable speed 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
variable speed 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 variable speed ECM blower will operate in high
speed. During the cooling cycle the reversing valve will be
commanded into the “ON” position.
Variable Speed 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
Controls - FX10 (optional) cont.
Summary of Contents for Aston Compact Series
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