AAON MODGAS-X, Техническое руководство

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19
MODGAS-X Technical Guide
Min Mode
1. The Min Mode will attempt to initialize after the first
stage of heat and any subsequent stage of heat.
2. If the Supply Air Temperature is below the Supply
Air Temperature Setpoint and within the Min Mode
Deadband. Min Mode will run for a user defined
interval set on the MinPosTP screen on page 27 .
3. After the runtime, it will continue into Heating Mode.
4. If the Min Mode Deadband is set to zero, this mode
will not be active and continue to Heating Mode.
Heating Mode
1. Once the module finalizes High Fire Mode, it will go
to Heating Mode.
2. In this mode, a unit with a 0-20 volt valve will
modulate between 25% (15 VDC) to 75% (5 VDC)
of the value range (which is displayed as 0-100%) to
maintain the desired Supply Air Setpoint. See Table 3,
this page .
3. The Supply Air Setpoint is sent by the AAON unit
controller when in Communications Mode, or is set
in the Setpoint screens through the LCD display when
in Stand-Alone Mode.
4. Once the unit enters the Heating Mode, it will stay
in this mode for the minimum runtime—default is
one minute.
5. The unit will exit the Heating Mode when the 24 VAC
Heat Enable Signal is removed or the Heat command
from the AAON unit controller is removed.
Low Speed Relay Operation
• 0-20 Volt Valve
1. If the valve modulates below 54.5% (9.1 VDC) for
five seconds, the Low Speed Relay will be activated.
2. The Low Speed relay will be deactivated if the valve
modulates above 55.5% (8.9 VDC) for five seconds.
• 0-10 Volt Valve
1. If the valve modulates below 33% (3.3 VDC) for
five seconds, the Low Speed Relay will be activated.
2. The Low Speed relay will be deactivated if the valve
modulates above 34% (3.4 VDC) for five seconds.
Additional Stages of Heat
If the MODGAS-X is controlling more than one Stage of Heat,
it will use the following staging sequence:
1. If the ModGas Valve Signal is at 100% for three
minutes (adjustable), the Aux Relays will stage up. If
the Supply Air Temperature is 32°F or less, the stage
up delay will reset to one minute.
2. If the ModGas Valve Signal is at 0% for one minute
(adjustable), the Aux Relays will stage down.
3. As the Aux Relays stage up/down, the ModGas Valve
will modulate as necessary to maintain setpoint.
Supply Air Setpoint Reset
1. In Stand-Alone Mode, the module will look at the
voltage of the Reset Signal to provide a setpoint
reset mechanism. This input is expecting a 0-10 VDC
signal.
2. When the Signal is at 0 VDC, the setpoint will be equal
to the SAT setpoint set in the LCD display.
3. When the Signal is a 10 VDC, the setpoint will be
equal to the Reset setpoint set in the LCD display.
4. The setpoint value will be reset proportionally from
the value set in the LCD display as the signal goes
from 0 to 10 VDC.
5. The Reset Setpoint can be above or below the Supply
Air Temperature Setpoint.
Cutoff Mode
1. If the Supply Air Temperature rises above 200°F, the
MODGAS-X will enter the Cutoff Mode.
2. In this mode, the MODGAS-X will completely shut
off.
3. This mode has higher priority than any other mode of
operation and needs to be cleared before the unit can
enter another mode.
4. The Cutoff Mode will be cleared if the Supply Air
Temperature drops below 190°F.
5. The Cutoff Mode will last at least five minutes.
SEQUENCE OF OPERATION
Operating Modes
0-20 Volt Valve
LCD Display Voltage Signal
0% 15 Volts 25%
100% 5 Volts 75%
0-10 Volt Stepper Valve
LCD Display Voltage Signal
0% 0 Volts 0%
100% 10 Volts 100%
Table 3: Heating Mode Voltage/Signal