NOTE: In diagnosing common faults in the cooling system, develop a logical
thought pattern as used by experienced technicians. The charts which follow are
not intended to be an answer to all problems but only to guide the technician’s
trouble shooting. Through a series of yes and no answers, follow the logical path to
a likely conclusion.
A novice technician should use these charts like a road map. Remember that the
chart should clarify a logical path to the solution.
18.1
Comfort Control
2
System™
System Initial Startup
Connect the system.
There are four wires that need to be connected to each unit.
R 24 VAC
C 24 VAC common
1 Communications
2 Communications
Air Handler
Air Conditioner
Furnace
Heat Pump
Thermostat
Indoor
Outdoor
R – – – – – – – – – – – – – – – – – – R – – – – – – – – – – – – – R
1 – – – – – – – – – – – – – – – – – – 1 – – – – – – – – – – – – – 1
2 – – – – – – – – – – – – – – – – – – 2 – – – – – – – – – – – – – 2
C – – – – – – – – – – – – – – – – – – C – – – – – – – – – – – – – C
These wires need to be connected to each device thermostat, indoor air handler
and outdoor unit (heat pump or AC). Verify the connectors on data lines 1 & 2 are
plugged together. The connectors are located on the inside of the control box in
front of ground lug.
If the communications wires (1 & 2) are crossed at any point the green LED (D52)
will always be on. If this happens check the wires at each point to ensure they are
not reversed.
Once all devices are connected, turn on the line and low voltage to the system.
When all devices are powered the thermostat should detect the indoor and outdoor
units within 60 seconds. The air handler and the primary control in the outdoor units
have a set of bias dipswitches set at a factory default to the ON position. The sec-
ondary control dipswitches are defaulted off. DO NOT CHANGE DIP SWITCHES.
Once the system is powered the airflow settings will be configured for all devices.
The outdoor unit will send information to configure indoor airflow. If the indoor unit is
incapable of supplying the required airflow a d3 fault will be displayed on the ther-
mostat and outdoor unit.
All devices have a LEARN button. This button is for future use and has no function
at this time.
IMPORTANT: DO NOT USE A PHONE CORD TO CONNECT INDOOR AND OUT-
DOOR UNITS. THIS WILL DAMAGE THE CONTROLS.
IMPORTANT: DO NOT CONNECT THE SYSTEM TO A PHONE LINE. THIS WILL
DAMAGE THE CONTROLS.
ADVANCED SETTINGS
All adjustments for airflow are made at the thermostat at this time. Items that can be
changed are Airflow trim adjustment, Dehumidification Setpoint and mode of opera-
tion. The thermostat also has a wide range of fault and history information. The fol-
lowing tables show all of the available options by unit type. To go down into a
menu, press Install Config. To move back up, press the Menu button. See the
Thermostat Installation Instructions for additional information.
18.2 REPLACEMENT OF
COMFORT CONTROL
2
SYSTEM™
CONTROL
18.2
BOARD
Each control board in the Comfort Control
2
System™ needs information specific to
the unit the control is installed in. This information is called shared data because it
is distributed (shared) on the HVAC network. The shared data for a unit contains
information that allows the unit to operate correctly.
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