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NDS OUTDOOR SPLIT INSTALLATION MANUAL
Cool, 2nd Stage (Y1, Y2, O) Dual Capacity Units
The second stage compressor will be activated 5 seconds
after receiving a “Y2” input as long as the minimum first
stage compressor run time of 1 minute has expired. The
ECM blower changes to high speed 15 seconds after the
“Y2” input (85% of high speed if in dehumidification mode).
The Comfort Alert will delay the second stage compressor
until 5 seconds after it receives a “Y2” from the board.
Blower (G only)
The blower starts on low speed (PSC ON). Regardless of
blower input “G” from thermostat, the blower will remain
on low speed for 30 seconds at the end of each heating,
cooling or emergency heat cycle.
Lockout Conditions
During lockout mode, the appropriate unit and thermostat
lockout LEDs will illuminate. The compressor, loop pump,
and accessory outputs are de-energized. The blower will
continue to run on low speed. If the thermostat calls for
heating, emergency heat operation will occur.
Comfort Alert lockouts cannot be reset at the thermostat.
All other lockout modes can be reset at the thermostat
after turning the unit off, then on, which restores normal
operation but keeps the unit lockout LED illuminated.
Interruption of power to the unit will reset a lockout
without a waiting period and clear all lockout LEDs.
High Pressure
This lockout mode occurs when the normally closed safety
switch is opened momentarily (set at 600 PSI).
Low Pressure
This lockout mode occurs when the normally closed low
pressure switch is opened for 30 continuous seconds (set
at 40 PSI). A low pressure fault may also be indicated when
a Comfort Alert lockout has occurred.
Freeze Detection (Water Flow)
This lockout mode occurs when the freeze detection
thermistor temperature is at or below the selected point
(well 30°F or loop 15°F) for 30 continuous seconds.
Microprocessor Control cont.
