Controls; Options; Operations Monitor; Compressor Low Ambient Cut-Off - Lennox XC21 Engineering Data

FEATURES
COMPRESSOR (CONTINUED)
Compressor is installed in the unit on specially
formulated, resilient rubber mounts for better sound
dampening and vibration free operation.
Crankcase Heater
Crankcase heater prevents migration of liquid
refrigerant into compressor and ensures proper
compressor lubrication.

CONTROLS

icomfort™ Control
I
Advanced control communicates
information about various
operating parameters in
the air conditioner to the
optional icomfort Touch™
Communicating Thermostat to
constantly maintain the highest
level of comfort, performance and
efficiency available.
Connections for connecting a
conventional heating/cooling
thermostat are also provided on
the control.
Auto Configuration - On start-up the control
automatically sends a description of the unit to
the optional icomfort Touch™ Communicating
Thermostat to automatically configure the number of
stages and features available.
Control also features:
• Compressor anti-short cycle delay. User selectable
with communicating thermostat - 1, 2, 3, 4 or 5
minutes. Default setting is 5 minutes.
Compressor must operate in first stage a minimum
of 5 seconds before second stage operation is
permitted.
• Low voltage protection prevents 2nd stage
compressor operation when voltage is not within the
specified range.
• High and low pressure switch monitoring with
provisions for lockout.
• Five-Strike lockout protection protects compressor.
• Discharge line temperature and sensor monitoring.
• Lennox Humiditrol Whole Home Dehumidification
®
System (EDA) compatible.
• EEPROM storage of all local configurations.
XC21 - 2 to 5 Ton Air Conditioner / Page 4
Lennox Systems Operations Monitor
(icomfort™ Control Feature)
Onboard Lennox Systems Operations Monitor (LSOM)
®
provides detailed information for proper preventative
maintenance and fast, easy servicing.
Displays the most common fault conditions (electrical
and mechanical) through the icomfort Touch™
Communicating Thermostat or through the ALERT
and TRIP lights on the control. ALERT LED (yellow) -
communicates an abnormal system condition through a
unique flash code. The ALERT LED will flash a number
of times consecutively, pause and then repeat the
process. The number of consecutive flashes, defined
as the Flash Code, correlates to a particular abnormal
condition. The codes can indicate one of the following:
long run time, system pressure trip (discharge or suction
pressure out-of-limits or compressor overloaded), short
cycling, locked rotor, open circuit, open start circuit
(current present only in run circuit), open run circuit
(current present only in start circuit), welded contactor
(compressor runs continuously), or low voltage (control
circuit < 17VAC). TRIP LED (red) - indicates there is a
demand signal from the thermostat but no current to the
compressor is detected by the monitor.

OPTIONS

Compressor Low Ambient Cut-Off

Non-adjustable switch (low ambient cut-out) prevents
compressor operation when outdoor temperature is
below 35°F.
Compressor Hard Start Kit
Single-phase units are equipped with a PSC
compressor motor.
This type of motor normally does not need a potential
relay and start capacitor.
In conditions such as low voltage, kit may be required to
increase the compressor starting torque.
Indoor Blower Off Delay Relay
Delays the indoor blower-off time during the cooling
cycle. Required if outdoor unit is used with a
conventional heating-cooling thermostat and air handler
(not icomfort™ control). See furnace or air handler
specifications to determine if relay is needed.
Indoor Blower Speed Relay Kit
Relay kit provides optimum humidity control conditions
by automatically reducing indoor blower speed during
continuous fan or first-stage compressor operation.
Low Ambient Kit
Air conditioner will operate satisfactorily down to 45°F
outdoor air temperature without any additional controls.
Kit can be added in the field enabling unit to operate
properly down to 30°F.
A Freezestat should be installed on compressors
equipped with a low ambient kit.
A Compressor Low Ambient Cut-Off should be added to
terminate compressor operation below recommended
operation conditions.