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EKW FX10 INSTALLATION MANUAL
3.7.2. S-Plan Mode
This mode allows externally selectable separate operation of domestic hot water or comfort conditioning.
If only the Y1/System Enable input (BI-7) is enabled, the heat pump will only operate for the domestic hot
water load. If the S-Plan Select Enable/POI (BI-10) is enabled and the Y1/System Enable input (BI-7) is not
enabled, the reversing valve will be positioned for heating and the heat pump will only operate for the comfort
heating. Compressor operation will be setpoint controlled based on the relationship of the load entering water
temperature and the setpoint. If both the Y1/System Enable (BI-7) and S-Plan Comfort Select Enable (BI-10)
are enabled, during the heating cycle, the reversing valve position will remain in the heating position. Com-
pressor operation will be time-shared in order to maintain setpoint temperature in a domestic hot water tank
and setpoint temperature in a chilled water loop suitable for fan coil cooling operation. Primary consideration
is given to the domestic hot water. A domestic hot water heating cycle will end once the setpoint is reached,
or after an adjustable time delay has expired. At the end of a domestic water heating cycle, the position of the
load water valve will be changed via BO-9, and a sampling period will begin for determining comfort heating
needs. If comfort heating is required, the reversing valve will remain positioned for heating and a comfort
heating cycle will begin. If the heating water loop entering water temperature is within setpoint requirements,
the controller switches to domestic hot water operation after a sampling delay. The compressor will be cycled in
response to the load entering water temperature/setpoint control logic. Accessory output 2 (X2) will be com-
manded on 60 seconds prior to compressor start and remain on for a delay of 30 seconds after the compressor
is turned off-suitable for load loop pump operation. Accessory output 2 is network and MUI configurable to run
continuous if the Y1/System Enable input is activated, or cycled. After the compressor output is turned off, it will
remain off for the time specified in the compressor short cycle time delay. Accessory Output 1 (X1) is cycled
with the compressor, suitable for source loop pump operation.
3.7.3. Aqua-stat Mode
During the heating cycle, the reversing valve will be positioned for heating operation. If an aqua-stat
is being used, the aqua-stat will command the reversing valve “Off” on a call for heating. When a Y call is
initiated, and the random restart delay timer is expired, accessory output 2 will turn on. If the compressor
short cycle time delay has been satisfied, the compressor and accessory output 1 will turn on after the fixed
compressor start delay timer has been satisfied. When heating is no longer required, the compressor and
accessory output 1 will be turned off immediately after the compressor minimum on delay has been satisfied.
After the compressor output is turned off, it will remain off for the time specified in the compressor short cycle
time delay. Accessory output 2 will be turned off 30 seconds after the compressor stops.
3.8. cooling cycle
3.8.1. setpoint mode
During the cooling cycle, the reversing valve position will be controlled by the internal temperature setpoint
control logic. Compressor and reversing valve operation will be time-shared in order to maintain setpoint
temperature in a domestic hot water tank and setpoint temperature in a chilled water loop suitable for fan coil
cooling operation. Primary consideration is given to the domestic hot water. A domestic hot water heating
cycle will end once the setpoint is reached, or after an adjustable time delay has expired. At the end of a
domestic water heating cycle, the position of the load water valve will be changed via BO-5, and a sampling
period will begin for determining comfort cooling needs. If cooling is required, the reversing valve will
positioned for cooling and a cooling cycle will begin. If the chilled water loop entering water temperature is
within setpoint requirements, the controller switches to domestic hot water operation after a sampling delay.
The compressor will be cycled in response to the load entering water temperature/setpoint control logic.
Accessory output 2 will be commanded on 60 seconds prior to compressor start and remain on for a delay of
30 seconds after the compressor is turned off-suitable for source loop pump operation. Accessory output 2 is
network and MUI configurable to run continuous if the Y1/System Enable input is activated, or cycled opera
-
tion. After the compressor output is turned off, it will remain off for the time specified in the compressor short
cycle time delay.