Micro-Air, Inc.
Page 24
EasyTouch 2.5 Operations Manual
Rev 1.0 8/27/14
There are 4 different Failsafe levels to choose from:
Faults Not Detected
- This level provides minimal failsafe protection and is not
recommended. Only the “Air Sensor” and the “Lost AC” fault will be detected and
displayed. No Lockout occurs at this failsafe level, except for the Air Sensor fault which
always causes a Lockout condition. All other faults will not be detected or displayed.
Faults Detected But Not Displayed
- This level provides the same actions of the
previous level, plus all other faults are detected but not displayed. When a fault is
detected, the system shuts down for 2 minutes or until the fault is cleared, whichever is
longer. The system will then restart automatically after the fault is cleared.
Faults Detected and Displayed
- This level provides the same actions of the previous
two levels, plus all faults are displayed. The system shuts down for 2 minutes or until the
fault is cleared, whichever is longer. The system restarts automatically when the fault is
cleared.
Faults Detected and Displayed with Lockout
- This level provides the failsafe actions
of previous 3 levels, plus the system will lockout after four consecutive High Pressure,
Low Pressure, or Pump Sentry faults. To clear the lockout, cycle the power at the display
by pressing the POWER button twice.
See section 9 for more information on all of the various faults that EasyTouch can declare.
11.2.3 Low Voltage Monitor (OFF / 75-120VAC or 175-240VAC);
OFF
)
The EasyTouch has a built-in voltmeter circuit that monitors the AC input voltage. Depending
on whether the AC input voltage is 115VAC or 230VAC, this parameter has two different
setting ranges. The factory default setting is OFF. When this parameter is set to 75-120VAC
(115VAC systems) or 175-240VAC (230VAC systems), the EasyTouch checks the AC input
voltage prior to each cooling or heating cycle and during regular operation.
Just prior to compressor startup, EasyTouch will immediately declare the LOW AC fault if
the voltage is less than this parameter setting. This provides extra protection for the
compressor and components within the system during low voltage starting conditions.
The LOW AC fault will persist until the AC input voltage goes above this parameter
setting or for a minimum of 2 minutes before allowing the compressor startup to proceed,
whichever occurs first.
After compressor startup, if the AC input voltage goes below this parameter setting for 5
minutes, the system will be shutdown and the LOW AC fault will be declared. The LOW
AC fault will persist until the AC input voltage goes above this parameter setting and a
fault delay of 2 minutes has occurred, whichever occurs first. Once the voltage is
restored, after the normal fault recovery delay, the compressor will be restarted.
The LOW AC fault does not contribute to the Lockout count.
11.2.4 De-Ice Cycle (OFF/ Enabled with 5°F/3°C Sensor Differential / Enabled with 7°F/4°C Sensor
Differential;
Enabled with 5°F/3°C Sensor Differential
)
The de-icing cycle prevents ice buildup on the evaporator coil during extended periods of
cooling operation. Installation variables such as grille sizes, length of ducting, insulation, and
ambient temperatures determine the runtime required to achieve set point. Factors that
substantially increase runtime include operating the system with hatches and doors open and
programming an unrealistic set point (e.g. 65°F/18°C). Such situations can cause the
evaporator to form ice on warm humid days. De-icing is accomplished by closely monitoring
the room air temperature in 10-minute intervals during a cooling cycle. Depending on the
parameter value and the change in room temperature during these monitoring intervals, the
control performs various actions to prevent ice from forming or to melt ice that has already
formed. This is accomplished by short compressor shutdown periods combined with a one-
speed increase in fan speed and by periodic Heat Mode cycles with the fan turned off. The
parameter setting for the de-icing feature depends on whether you are using the optional
alternate air temperature se
nsor or the display’s built-in inside air temperature sensor.
Installation of an optional alternate air temperature sensor (located in the return air path)
greatly increases the effectiveness of the de-icing feature, and this option should be
considered whenever the display sensor cannot read the room temperature accurately.
