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4) 3 step fan speed control for
2 stage thermostats
(Y1 and Y2 connection)
SW2-9 and 2-10
5) Cold wind prevention
SW2-11
6) Fan stop control during
defrost operation
SW2-12
•
This can only be turned on when a 2-stage thermostat is used.
•
The fan speed control logic is as follows:
–
High: Used during Stage 2 operation
–
Mid: Used during Stage 1 operation
–
Low: Used when operation in Mid speed continues for 30 minutes
–
Fan speed changes to High if a Stage 2 signal is input during operation in Mid/
Low fan speed mode.
•
Stage 1 performance control logic: If the mode switches to Stage 1 from Stage 2 due
to a decrease in the difference between the set temperature and indoor temperature
and then the mode returns to Stage 2 due to a failure to reach the set temperature
because of low performance of Stage 1, the target pressure for Stage 1 is calibrated
when the mode switches to Stage 1, to increase the performance of Stage 1.
•
G1 (Low) / G2 (Mid) / G3 (High) signals will also be enabled simultaneously.
•
Stops the fan until the heat exchanger warms up to prevent cold air during the initial
stage of heating operation.
•
The fan operates if high pressure increases to 290 psi or more during the initial stage
of heating operation.
•
When this feature is activated, the fan will remain idle for a maximum of 5 minutes.
CAUTION
•
When set to enable, this feature is activated when the compressor starts
operation in heating mode to keep the fan off while the compressor is operating.
Once the compressor starts operation, the fan is kept off during the control
regardless of whether the fan is set to non-stop from the thermostat.
•
Prevents cold air during defrost operation by stopping the fan.
•
Stops fan operation when the heat pump enters defrost mode and keeps the fan
stopped until the defrost operation is complete.
•
If this feature is set to Disable, after a defrost cycle begins the W1 output terminal
on the AHU Control Unit (ACU) will continue outputting 24VAC until the defrost
operation is complete.
CAUTION
•
When this feature is set to Enable, it may take longer to complete defrost cycles
compared to when it is set to Disable. This feature is disabled if low pressure
decreases to 14 psi or lower during defrost operation or if frost is still found after
a defrost cycle is complete. This issue may occur if the indoor heat exchanger size
is too small for the outdoor capacity or there is a problem with the thermostatic
expansion valve (TXV) calibration.
Option setting details
English
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