AAON RSMVQ2R, Техническое руководство

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RSMVQ2R Technical Guide
SEQUENCE OF OPERATIONS
Cooling Mode and Dehumidification Operation
Cooling Mode Operation
Cooling mode control staging is determined by the supply air
temperature. Staging is met by turning the on/off compressor on
or off and the two-step compressor to low speed or high speed.
Compressor modulation (VFD) is determined from saturation
temperature and supply air temperature. If the supply AND
saturation temperature are above setpoint, the compressors will
modulate up. If the supply OR saturation temperature are below
setpoint, the compressors will modulate down. Envelope and/or
current protections also affect the VFD compressor modulation.
Staging Up
1. If the supply air temperature is above the setpoint,
Compressor 1 VFD will turn on at the recommended
manufacturer’s specified speed for one minute.
Compressor 1 VFD will modulate anytime thereafter
if it is running.
2. If the supply air temperature is above the setpoint
plus window, and Compressor 1 VFD is at 100% of
its capacity, Compressor 2 will turn on at low speed
and Compressor 1 will be reset to 67% of its range
(min to max).
3. If the supply air temperature is above the setpoint
plus window, and Compressor 1 VFD is at 100% of
its capacity, Compressor 2 will be set to high speed
and Compressor 1 will be reset to 67% of its range
(min to max).
Staging Down
1. If the supply air temperature is below the setpoint
plus window and Compressor 1 VFD is at minimum
capacity, Compressor 2 will be set to low speed and
Compressor 1 will be reset to 67% of its range (min
to max).
2. If the supply air temperature is below the setpoint
plus window, and Compressor 1 VFD is at minimum
capacity, Compressor 2 will be turned off and
Compressor 1 will be reset to 67% of its range (min
to max).
3. If the supply air temperature is below the setpoint
plus window, and Compressor 1 VFD is at minimum
capacity, Compressor 1 will be turned off.
4. If the supply air temperature rises above the setpoint
and Compressor 1 VFD’s minimum off time has been
met, Compressor 1 will be turned back on.
Dehumidification Operation
Dehumidification Mode control staging/modulation is determined
by using the lowest saturation temperature from each circuit.
Circuit 1 uses DMQ saturation temperature and Circuit 2 uses
the saturation coil temperature sensor (Temp 2 input) mounted
after the TXV.
Staging Up
1. Staging begins when the module obtains the Reheat
Valve position and Reheat Supply Air Error from the
main unit controller (VCCX2). Compressor 2 will
turn on at low speed.
2. If the saturation temperature (lowest of both circuits’
readings) is above the setpoint plus window,
Compressor 1 VFD will turn on at the recommended
manufacturer’s specified speed for one minute.
Compressor 1 VFD will modulate any time thereafter
based on the saturation temperature (lowest of both
circuit’s readings).
3. If the saturation temperature of Circuit 2 is above the
setpoint plus window, Compressor 1 VFD is at 67% of
its range min to max, the reheat valve is at 100%, and
the supply air temperature is below the reheat setpoint,
Compressor 2 will be set to high speed.
Staging Down
1. If the saturation temperature of Circuit 2 is below the
setpoint plus window, Compressor 1 VFD is below
50% (adjustable), and the reheat valve is below 50%,
Compressor 2 will be set to low speed.
2. If the saturation temperature of Circuit 1 is below the
setpoint plus window and Compressor 1 VFD is at
minimum, Compressor 1 will be staged off.
Compressor 2 cannot be turned off in Dehumidification Mode
unless failed on safety.